Embodiments of this invention are directed generally to microbiology and medicine. In certain aspects there are methods and compositions relating to treatment of Staphylococcus infection.
Staphylococcus aureus is a commensal of the human skin and nares as well as an invasive pathogen causing soft tissue infections, sepsis, endocarditis and pneumonia (Lowy 1998). Owing to the frequent use of antibiotics, staphylococci frequently evolved resistance to drugs (DeLeo et al. 2010 and Neu 1992). These methicillin-resistant S. aureus strains (MRSA) are associated with therapeutic failure and increased mortality of staphylococcal infections (Klevens et al. 2007 and Klevens et al. 2008). Of note, vancomycin-resistance recently emerged due to the transfer of resistance genes from glycopeptide (vancomycin)-resistant enterococci to MRSA strains (Weigel et al. 2003). The resulting VRSA strains are virtually resistant to all available antibiotics (Tenover et al. 2001). Expanded use of antibiotics in Asia has triggered increases in community-acquired infections with MRSA and the emergence hypervirulent strains, indicating that drug-resistant Gram-positive bacteria represent a global threat (Li et al. 2012). Two drugs, daptomycin and linezolid, have been recently been licensed for the treatment of MRSA infections (Arbeit et al. 2004 and Stevens et al. 2002). However, MRSA strains already evolved resistance against these new antibiotics, revealing the continuous need for new drug targets and for the development of new antibiotics to combat S. aureus infections (van Hal and Paterson 2011).
The crisis in antibiotic resistance applies not only to MRSA but also to other Gram-positive bacteria causing significant clinical disease, for example vancomycin (glycopeptide)-resistant enterococci (E. faecium and E. faecalis), as well as drug-resistant Staphylococcus epidermidis, Clostridum difficile, and Streptococcus pneumoniae (Willems et al. 2011).
Therefore, there is an increased need for developing alternative antibiotics that are structurally unrelated to known antibiotics and that are targeting novel pathways in pathogens.
Staphylococcus aureus remains a leading cause of infectious disease morbidity and mortality. Lipoteichoic acid (LTA) is an abundant secondary cell wall polymer of Gram-positive bacteria and consists of repeating units of 1,3-glycerol phosphate or polyglycerophosphate, linked to a membrane anchor. LTA synthase (LtaS) catalyzes the transfer of glycerophosphate from phosphatidylglycerol to the growing chain of polyglycerophosphate on the trans side of the plasma membrane. Genetic disruption of polyglycerophosphate synthesis is poorly tolerated and loss of LTA leads to cessation of bacterial growth.
Methods and compositions concern an LtaS inhibitor for preventing or treating a Gram-positive infection. In some embodiments, the LtaS inhibitor has the following structure:
In some embodiments, an LtaS inhibitor comprises a compound of formula I or a pharmaceutically acceptable salt thereof. In specific embodiments, the hydrophobic double-ring structure is naphthofuran. In certain embodiments, the compound is 2-oxo-2-(5-phenyl-1,3,4-oxadiazol-2-ylamino)ethyl 2-naphtho[2,1-b]furan-1-ylacetate, or a salt thereof.
Certain embodiments are directed to methods of inhibiting a Gram-positive bacterial infection in a patient comprising administering to the patient a composition comprising a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises an oxadiazole ring. In particular embodiments, the patient is administered an amount of the composition that has been previously shown to be an effective amount.
Additional embodiments concern methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises an oxadiazole ring.
In other embodiments there are methods for inhibiting Gram-positive bacteria comprising administering to the bacteria a compound having the following structure:
In some embodiments, a method for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprises administering a compound having the formula:
wherein R1 is methylene or NH; R2 is a hydrogen atom, a benzyl group or an oxadiazole ring; and R3 is a benzofuran, a naphthofuran, an indole group, or a phenyl ring. In some embodiments, methods and compositions comprise administration of an LtaS inhibitor of formula II. Certain embodiments are directed to methods of inhibiting a Gram-positive bacterial infection in a patient comprising administering to the patient a composition comprising a compound of formula II, or a pharmaceutically acceptable salt thereof.
In some embodiments, R2 is a 2-substituted oxadiazole ring. In other embodiments, the oxadiazole ring is substituted with a phenyl ring. In a further embodiment, the benzyl group is a substituted benzyl group. In yet other embodiments, the benzyl group is substituted with an alkyl group at the benzylic position. In some embodiments, the benzofuran is substituted at adjacent positions with two alkyl groups. In some embodiments, the two alkyl groups together form a ring. In a further embodiment, R1 is methylene, R2 is a hydrogen atom, and R3 is a naphthofuran. In yet a further embodiment, R1 is NH, R2 is a benzyl group substituted at the benzylic position with an alkyl group, and R3 is a naphthofuran. In some embodiments R1 is NH, R2 is an oxadiazole ring substituted with a phenyl ring, and R3 is a phenyl ring, a naphthofuran, an indole group, or a benzofuran substituted at adjacent positions with two alkyl groups, wherein the two alkyl groups may together form a ring.
In specific embodiments, the compound is 2-oxo-2-(5-phenyl-1,3,4-oxadiazol-2-ylamino)ethyl 2-(naphtho[2,1-b]furan-1-yl)acetate. In specific embodiments, the compound is 2-oxopropyl 2-(naphtho[2,1-b]furan-1-yl)acetate. In specific embodiments, the compound is 2-(methylamino)-2-oxoethyl 2-(naphtho[2,1-b]furan-1-yl)acetate. In specific embodiments, the compound is 2-oxo-2-(1-phenylethylamino)ethyl 2-(naphtho[2,1-b]furan-1-yl)acetate. In specific embodiments, the compound is 2-oxo-2-(5-phenyl-1,3,4-oxadiazol-2-ylamino)ethyl 2-phenylacetate. In specific embodiments, the compound is 2-oxo-2-(5-phenyl-1,3,4-oxadiazol-2-ylamino)ethyl 2-(1H-indol-3-yl)acetate. In specific embodiments, the compound is 2-oxo-2-(5-phenyl-1,3,4-oxadiazol-2-ylamino)ethyl 2-(5,6-dimethylbenzofuran-3-yl)acetate. In specific embodiments, the compound is 2-oxo-2-(5-phenyl-1,3,4-oxadiazol-2-ylamino)ethyl 2-(6,7-dihydro-5H-indeno[5,6-b]furan-3-yl)acetate. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises an oxadiazole ring are provided. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a compound of formula II are provided.
In some embodiments, a method of inhibiting a Gram-positive bacterial infection in a patient comprising administering to the patient a composition comprising a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a compound having the formula:
wherein R1 is an alkyl group, cycloalkyl group, alkyl ether, alkyl thioether, phenyl ring, or heterocycle; and R2 and R3 are each, independently, an alkyl group, a benzyl group, a phenyl group, or R2 and R3 together form part of a piperidine ring. In some embodiments, methods and compositions comprise administration of an LtaS inhibitor of formula III. Certain embodiments are directed to methods of inhibiting a Gram-positive bacterial infection in a patient comprising administering to the patient a composition comprising a compound of formula III, or a pharmaceutically acceptable salt thereof.
In some embodiments, R1 is an alkyl group, cycloalkyl group, alkyl ether, alkyl thioether, phenyl group, or heterocycle. In a further embodiment, the phenyl ring is substituted with one or more alkoxy groups. In some embodiments, R2 and R3 are each, independently an alkyl group, a benzyl group, or a phenyl group. In further embodiments, R2 and R3 together form part of a piperidine ring. In some embodiments, the piperidine ring is substituted with an alkyl group.
In specific embodiments, the compound is 4-(2-methylpiperidin-1-ylsulfonyl)-N-(5-(methylthiomethyl)-1,3,4-oxadiazol-2-yl)benzamide. In specific embodiments, the compound is 4-(N-benzyl-N-isopropylsulfamoyl)-N-(5-(3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)benzamide. In specific embodiments, the compound is 4-(2-methylpiperidin-1-ylsulfonyl)-N-(5-(thiophen-2-yl)-1,3,4-oxadiazol-2-yl)benzamide. In specific embodiments, the compound is 4-(N-butyl-N-ethylsulfamoyl)-N-(5-(methoxymethyl)-1,3,4-oxadiazol-2-yl)benzamide. In specific embodiments, the compound is 4-(N,N-diisobutylsulfamoyl)-N-(5-methyl-1,3,4-oxadiazol-2-yl)benzamide. In specific embodiments, the compound is N-(5-(3,5-dimethoxyphenyl)-1,3,4-oxadiazol-2-yl)-4-(N-methyl-N-phenylsulfamoyl)benzamide. In specific embodiments, the compound is N-(5-cyclopropyl-1,3,4-oxadiazol-2-yl)-4-(2-methylpiperidin-1-ylsulfonyl)benzamide.
Additional embodiments concern methods for inhibiting lipoteichoic acid synthesis in a Gram positive bacteria comprising administering to the bacteria a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises an oxadiazole ring.
In further embodiments there are methods of treating a subject having or at risk of developing a Gram-positive bacteria infection comprising administering an effective amount of a pharmaceutically acceptable composition comprising an LtaS inhibitor having an oxadiazole ring. Further embodiments concern methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a 2-oxadiazolyl-4-(sulfonamide)benzamide. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram positive bacteria comprising administering to the bacteria a compound of formula III are provided.
In some embodiments, there is a method of inhibiting a Gram-positive bacteria infection in a patient comprising administering to the patient a composition comprising a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a compound having the formula:
wherein R1, R2, R3, R4, and R5 are each, independently, a hydrogen atom, an alkyl group or a halogen atom, provided at least 1 position on the phenyl ring is substituted with an alkyl group or halogen atom. In some embodiments, at least one of R2, R3 or R5 are substituted with an alkyl group or a halogen atom. In some embodiments, methods and compositions comprise administration of an LtaS inhibitor of formula IV. Certain embodiments are directed to methods of inhibiting a Gram-positive bacterial infection in a patient comprising administering to the patient a composition comprising a compound of formula IV, or a pharmaceutically acceptable salt thereof.
In specific embodiments, the compound is 2-(3,5-dimethyl-1H-pyrazol-1-yl)-6-methyl-N-o-tolylpyrimidin-4-amine. In specific embodiments, the compound is 2-(3,5-dimethyl-1H-pyrazol-1-yl)-N-(5-fluoro-2-methylphenyl)-6-methylpyrimidin-4-amine. In specific embodiments, the compound is 2-(3,5-dimethyl-1H-pyrazol-1-yl)-6-methyl-N-m-tolylpyrimidin-4-amine. In specific embodiments, the compound is 2-(3,5-dimethyl-1H-pyrazol-1-yl)-6-methyl-N-p-tolylpyrimidin-4-amine. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a 4-methylpyrimidine ring are provided. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a compound of formula IV are provided.
In some embodiments, there is a method of inhibiting a Gram-positive bacteria infection in a patient comprising administering to the patient a composition comprising a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a compound having the formula:
wherein R1 is a hydrogen atom or a substituted or unsubstituted benzyl group, R2 is an alkyl group or a substituted or unsubstituted phenyl group, R3 is a hydrogen atom or an alkyl group, and R4 is a phenyl group, an N-benzyl amide, or an N-2-(phenyl)-ethyl group. In some embodiments, methods and compositions comprise administration of an LtaS inhibitor of formula V. Certain embodiments are directed to methods of inhibiting a Gram-positive bacterial infection in a patient comprising administering to the patient a composition comprising a compound of formula V, or a pharmaceutically acceptable salt thereof.
In some embodiments, R1 is 4-chlorobenzyl, 3-chlorobenzyl, or 2-chloro-4-fluorobenzyl. In some embodiments, R2 is a methyl group or 4-chlorophenyl. In some embodiments, R3 is a hydrogen atom or methyl. In some embodiments, R4 is phenyl, N-2-chlorobenzyl amide, N-4-methylbenzyl amide, N-(phenylethyl) amide, or N-(4-chlorophenethyl) amide.
In some embodiments, the compound is 6-(4-chlorobenzyl)-N-(4-chlorophenethyl)-7-hydroxy-5-methylpyrazolo[1,5-a]pyrimidine-3-carboxamide. In some embodiments, the compound is N-(2-chlorobenzyl)-6-(3-chlorobenzyl)-7-hydroxy-5-methylpyrazolo[1,5-a]pyrimidine-3-carboxamide. In some embodiments, the compound is 6-(2-chloro-4-fluorobenzyl)-7-hydroxy-5-methyl-N-(4-methylbenzyl)pyrazolo[1,5-a]pyrimidine-3-carboxamide. In some embodiments, the compound is 6-(2-chloro-4-fluorobenzyl)-7-hydroxy-5-methyl-N-(4-methylbenzyl)pyrazolo[1,5-a]pyrimidine-3-carboxamide. In some embodiments, the compound is 6-(2-chloro-4-fluorobenzyl)-7-hydroxy-5-methyl-N-phenethylpyrazolo[1,5-a]pyrimidine-3-carboxamide. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a pyrazolo[1,5-a]pyrimidine bicyclic are provided. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a compound of formula V are provided.
In some embodiments, there is a method of inhibiting a Gram-positive bacteria infection in a patient comprising administering to the patient a composition comprising a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a compound having the formula:
wherein R is 1-ethyl-3-iminoindolin-2-one or 5-isopropyloxazol-4(5H)-one. In some embodiments, the compound is (Z)—N-(3,4-dichlorophenyl)-2-(1-ethyl-2-oxoindolin-3-ylidene)hydrazinecarboxamide. In some embodiments, the compound is 1-(3,4-dichlorophenyl)-3-(5-isopropyl-4-oxo-4,5-dihydrooxazol-2-yl)urea. In some embodiments, methods and compositions comprise administration of an LtaS inhibitor of formula VI. Certain embodiments are directed to methods of inhibiting a Gram-positive bacterial infection in a patient comprising administering to the patient a composition comprising a compound of formula VI, or a pharmaceutically acceptable salt thereof.
In some embodiments, the compound is (Z)—N-(3,4-dichlorophenyl)-2-(1-ethyl-2-oxoindolin-3-ylidene)hydrazinecarboxamide. in some embodiments, the compound is 1-(3,4-dichlorophenyl)-3-(5-isopropyl-4-oxo-4,5-dihydrooxazol-2-yl)urea. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a 1-(3,4-dichlorophenyl)urea are provided. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a compound of formula VI are provided.
In some embodiments, there is a method of inhibiting a Gram-positive bacteria infection in a patient comprising administering to the patient a composition comprising a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a compound having the formula:
wherein R1 and R2 are each, independently, an alkyl group or R1 and R2 together form a carbocyclic ring, R3 is a pyridinyl group or an alkylamine, and R4 is a thiol group or a N-methyl-1-(5-methylfuran-2-yl)methanamine group. In some embodiments, methods and compositions comprise administration of an LtaS inhibitor of formula VII. Certain embodiments are directed to methods of inhibiting a Gram-positive bacterial infection in a patient comprising administering to the patient a composition comprising a compound of formula VII, or a pharmaceutically acceptable salt thereof.
In some embodiments, the compound is 5,6-(cycloehexyl)-4-[N-methyl-1-(5-methylfuran-2-yl)methanamine]-2-(3-pyridinyl)-thieno[2,3-d]pyrimidine. In some embodiments, the compound is 5,6-dimethyl-2-(N,N-diethyl)methaneamine-thieno[2,3-d]pyrimidine-4thiol. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a thieno[2,3-d]pyrimidine are provided. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a compound of formula VII are provided.
In some embodiments, there is a method of inhibiting a Gram-positive bacteria infection in a patient comprising administering to the patient a composition comprising a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a compound having the formula:
wherein R1, R2, R3, R4, and R5 are each, independently, a hydrogen atom, an alkyl group or a halogen atom, provided at least 1 position on the phenyl ring is substituted with an alkyl group or halogen atom; and R6 and R7 are each, independently, an alkyl group or R6 and R7 together form a carbocylic ring, wherein one or more carbon atoms can be replaced with two heteroatoms, provided that two oxygens are not adjacent to each other. In some embodiments, at least one of R1, R2 or R4 are substituted with an alkyl group or a halogen atom. In some embodiments R6 and R7 are alkyl groups. In some embodiments, R6 and R7 form a 6 membered carbocyclic ring wherein oxygen atoms are present at the R6 and R7 positions. in some embodiments, at least one of R1, R2 or R4 are substituted with an alkyl group or a halogen atom and R6 and R7 are alkyl groups. In some embodiments at least one of R1, R2 or R4 are substituted with an alkyl group or a halogen atom and R6 and R7 form a 6 membered carbocyclic ring wherein oxygen atoms are present at the R6 and R7 positions. In some embodiments, methods and compositions comprise administration of an LtaS inhibitor of formula VIII. Certain embodiments are directed to methods of inhibiting a Gram-positive bacterial infection in a patient comprising administering to the patient a composition comprising a compound of formula VIII, or a pharmaceutically acceptable salt thereof.
In some embodiments, the compound is 2-chlorophenyl 5-(3,4-dimethylphenyl)isoxazole-3-carboxylate. In some embodiments, the compound is m-tolyl 5-(3,4-dimethylphenyl)isoxazole-3-carboxylate. In some embodiments, the compound is m-tolyl 5-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)isoxazole-3-carboxylate. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises an isoxazole are provided. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a compound of formula VIII are provided.
In some embodiments, there is a method of inhibiting a Gram-positive bacteria infection in a patient comprising administering to the patient a composition comprising a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a compound having the formula:
wherein R1 is alkyl or furanyl and R2 is alkyl. In some embodiments, R1 is methyl, ethyl or 2-furanyl. In some embodiments, R2 is ethyl or butyl. In some embodiments, methods and compositions comprise administration of an LtaS inhibitor of formula IX. Certain embodiments are directed to methods of inhibiting a Gram-positive bacterial infection in a patient comprising administering to the patient a composition comprising a compound of formula IX, or a pharmaceutically acceptable salt thereof.
In some embodiments, the compound is (3-benzoyl-2-butyl-1,1-dioxo-1-lambda6,2-benzothiazin-4-yl) propanoate. In some embodiments, the compound is (3-benzoyl-2-butyl-1,1-dioxo-1-lambda6,2-benzothiazin-4-yl) acetate. In some embodiments, the compound is (3-benzoyl-2-ethyl-1,1-dioxo-1-lambda6,2-benzothiazin-4-yl)2-furanoate. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a dioxo-1-lambda6,2-benzothiazinyl are provided. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a compound of formula IX are provided.
In some embodiments, there is a method of inhibiting a Gram-positive bacteria infection in a patient comprising administering to the patient a composition comprising a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a compound having the formula:
wherein R1 is alkyl and R2 is N-cyclopentanecarboxamide or 1-(naphthalen-1-yl)pyrrolidin-2-one. In some embodiments, methods and compositions comprise administration of an LtaS inhibitor of formula X. Certain embodiments are directed to methods of inhibiting a Gram-positive bacterial infection in a patient comprising administering to the patient a composition comprising a compound of formula X, or a pharmaceutically acceptable salt thereof.
In some embodiments, the compound is 4-(1-methyl-1H-benzo[d]imidazol-2-yl)-1-(naphthalen-1-yl)pyrrolidin-2-one. In some embodiments, the compound is N-(1-propyl-1H-benzo[d]imidazol-2-yl)cyclopentanecarboxamide. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a 1H-benzo[d]imidazole are provided. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a compound of formula X are provided.
In some embodiments, there is a method of inhibiting a Gram-positive bacteria infection in a patient comprising administering to the patient a composition comprising a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a compound having the formula:
wherein R1 is H and R2 is 1,1,1,3,3,3-hexafluoro-2-methoxypropan-2-ylamine or R1 and R2 may join to form 4-isopentyl-3-methyl-1H-pyrazol-5(4H)-one. In some embodiments, methods and compositions comprise administration of an LtaS inhibitor of formula XI. Certain embodiments are directed to methods of inhibiting a Gram-positive bacterial infection in a patient comprising administering to the patient a composition comprising a compound of formula XI, or a pharmaceutically acceptable salt thereof.
In some embodiments, the compound is 1-(benzo[d]thiazol-2-yl)-3-(1,1,1,3,3,3-hexafluoro-2-methoxypropan-2-yl)urea. In some embodiments, the compound is 1-(benzo[d]thiazol-2-yl)-4-isopentyl-3-methyl-1H-pyrazol-5(4H)-one. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a benzo[d]thiazole are provided. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a compound of formula XI are provided.
In some embodiments, there is a method of inhibiting a Gram-positive bacteria infection in a patient comprising administering to the patient a composition comprising a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a compound having the formula:
wherein R1 is a hydrogen atom or an N-alkyl-N-amide and R2 is an akyl or an N-alkyl-N-amide, R3 is alkyl or 5-chloro-1-ethyl-3-iminoindolin-2-one and R4 is hydrogen or benzyl. In some embodiments, R1 and R2 join to form a bis-lactam ring. In some embodiments, methods and compositions comprise administration of an LtaS inhibitor of formula XII. Certain embodiments are directed to methods of inhibiting a Gram-positive bacterial infection in a patient comprising administering to the patient a composition comprising a compound of formula XII, or a pharmaceutically acceptable salt thereof.
In some embodiments, the compound is N-benzyl-N,1,5-trimethyl-2,4-dioxo-2,3,4,5-tetrahydro-1H-benzo[b][1,4]diazepine-7-sulfonamide. In some embodiments, the compound is (E)-N′-(5-chloro-1-ethyl-2-oxoindolin-3-ylidene)-4-methylbenzenesulfonohydrazide. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a benzenesulfonamide are provided. In some embodiments, methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a compound of formula XII are provided.
In some embodiments methods and compositions concern an LtaS inhibitor that comprises a compound of any of formula I through XII, or a pharmaceutically acceptable salt thereof, for preventing or treating a Gram-positive infection. Additional embodiments concern methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a compound of any of formula I through XII, or a pharmaceutically acceptable salt thereof. Methods and compositions concern an LtaS inhibitor that comprises a compound of any of formula I through XII, or a pharmaceutically acceptable salt thereof, for preventing or treating a Gram-positive infection. Additional embodiments concern methods for inhibiting lipoteichoic acid synthesis in a Gram-positive bacteria comprising administering to the bacteria a lipoteichoic acid synthesis inhibitor, for example, a lipoteichoic acid synthase (LtaS) inhibitor, that comprises a compound of any of formula I through XII, or a pharmaceutically acceptable salt thereof. In other embodiments there are methods for inhibiting Gram-positive bacteria comprising administering to the bacteria a compound of any of formula I through XII, or a pharmaceutically acceptable salt thereof.
In some embodiments, methods relate to an infection in which the Gram-positive bacteria is Staphylococcus aureus. In further embodiments, the Staphylococcus aureus is a drug resistant Staphylococcus aureus. In certain embodiments, the drug resistant Staphylococcus aureus is methicillin-resistant Staphylococcus aureus (MRSA). In other embodiments, methods relate to an infection in which the Gram-positive bacteria is Bacillus anthracis. In additional embodiments, the Gram-positive bacteria is Enterococcus faecium. In further embodiments, the Gram-positive bacteria is vancomycin-resistant Enterococcus faecium.
In other embodiments, methods may apply to other Gram-positive bacteria whose group includes, but is not limited to, Staphylococcus epidermidis, Staphylococcus saprophyticus, Streptococcus pneumonia, Streptococcus pyrogens, Streptococcus agalactiae, Enterococcim Streptococcus viridians, Clostridium tetani, Clostridium botulinum, Clostridium perfringes, Clostridium difficile, Clostridiun scindens, Bacillus anthracis, Bacillus cereus, and Listeria monocytogenes. In certain embodiments, an LtaS inhibitor is more effective at inhibiting certain Gram-positive bacteria, such as Staphylococcus aureus, Bacillus anthracis and/or Enterococcus faecium, relative to Gram-negative bacteria, such as E. coli or any other Gram-negative bacteria (particularly those discussed in this paragraph). In some embodiments, the LtaS inhibitor has less than about 50, 40, 30, 20, 10, 5 or less percent of the inhibiting activity against E. coli as compared to Staphylococcus aureus, Bacillus anthracis and/or Enterococcus faecium (or any other Gram-positive bacteria) (based on assays described, for instance, in the Examples).
In some embodiments, methods concern an LtaS inhibitor that comprises a compound of any of formula I through XII, or a pharmaceutically acceptable salt thereof, that disturbs cell envelope architecture. In other embodiments, the LtaS inhibitor inhibits heterologous LTA synthesis in E. coli. In additional embodiments, the LtaS inhibitor competes with phosphatidylglycerol (PG).
In additional embodiments, there are methods that further comprise administering a second anti-microbial treatment. Some aspects concern a second anti-microbial treatment that is an antibiotic agent, an anti-infective agent, a passive vaccine or an active vaccine.
In additional methods, the patient has been determined to have a Gram-positive bacterial infection. Methods may involve identifying the patient as having a Gram-positive bacterial infection. They may also involve selecting the patient after the patient is diagnosed with a Staphylococcal infection. In some embodiments, there are methods in which the patient has been determined to have or be at risk of developing a Gram-positive bacterial infection. Some embodiments include testing the patient for a Gram-positive bacterial infection. For instance, some aspects further concern obtaining from the patient a biological sample for testing whether the patient has a Gram-positive bacterial infection.
In some methods the patient is at risk of a Gram-positive bacterial infection, particularly a Gram-positive bacteria that can lead to a medical issue, condition or disease, such as one requiring treatment. In particular examples the patient is at risk for a Staphylococcus bacterial infection. Some aspects concern a patient who is immune deficient, is immune-compromised, is hospitalized, is undergoing an invasive medical procedure, is infected with influenza virus or is on a respirator. In particular situations, the patient has pneumonia, sepsis, corneal infection, skin infection, infection of the central nervous system, or toxic shock syndrome. In certain instances, the patient exhibits a skin abscess, a boil, or a furuncle.
In some embodiments, there are methods that involve monitoring the patient for the Gram-positive bacterial infection within a week of first administering a therapeutic composition or LtaS inhibitor.
The methods can include treating a subject having or at risk of developing a Staphylococcal infection comprising administering an effective amount of an LtaS inhibitor to a subject having or at risk of developing a Staphylococcal infection.
The methods can also include inhibiting, attenuating, treating, or ameliorating toxic-shock syndrome and its related pathology.
In a further aspect, an LtaS inhibitor that comprises a compound of any of formula I through XII, or a pharmaceutically acceptable salt thereof, is administered orally, topically, nasally, intravenously, intravascularly, intrathecally, intratracheally, by inhalation, or by instillation. The LtaS inhibitor can be administered to various organs or tissues including, but not limited to the subject's skin, respiratory tract (including the lungs) kidneys, central nervous system, reproductive organs, vagina, or eyes.
In certain aspects, the Staphylococcal infection is a Staphylococcus aureus infection. In a further aspect the Staphylococcus aureus infection is a drug resistant Staphylococcus aureus infection. In still another aspect the drug resistant Staphylococcus aureus infection is a methicillin-resistant Staphylococcus aureus (MRSA) infection.
The method can also further comprise the step of testing the patient for a pathogenic bacterial infection. The method can include obtaining from the patient a biological sample for testing whether the patient has a pathogenic bacterial infection. In additional embodiments, the patient is tested for the type of pathogenic bacterial infection. In certain embodiments, the patient is tested for MRSA or pneumonia.
In certain aspects of the methods the patient is determined to have a Staphylococcal infection. The methods can further comprise identifying the patient as having a Staphylococcal infection. In a further aspect the method can further comprise selecting the patient after the patient is diagnosed with a Staphylococcal infection. The method can also further comprise the step of testing the patient for a Staphylococcal infection. The method can include obtaining from the patient a biological sample for testing whether the patient has a Staphylococcal infection. In additional embodiments, the patient is tested for the type of Staphylococcal infection. In certain embodiments, the patient is tested for MRSA or pneumonia.
In certain aspects of the methods the patient is determined to have a Streptococcus or Staphylococcus infection or some other Gram-positive bacterial infection. The methods can further comprise identifying the patient as having a Staphylococcus or Streptococcus infection. In a further aspect the method can further comprise selecting the patient after the patient is diagnosed with a Streptococcus infection. The method can also further comprise the step of testing the patient for a Streptococcus infection. The method can include obtaining from the patient a biological sample for testing whether the patient has a Streptococcus infection. In additional embodiments, the patient is tested for the type of Streptococcus infection. In certain embodiments, the patient is tested for pneumonia.
A patient is a human patient in some embodiments. It is contemplated that any embodiment involving a patient may also be applied to a subject, which refers to any organism that suffers physiologically as a result from infection by a Gram-positive bacteria.
In certain embodiments, the subject is a mammal, which includes but is not limited to dogs, cats, cows, horses, pigs, monkeys, and sheep.
In certain aspects a patient is administered an LtaS inhibitor within at least about, at most about, or about 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 hours, days, or weeks of being determined to have a Gram-positive infection.
Methods may involve administering a composition containing about, at least about, or at most about 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7. 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0, 18.5, 19.0. 19.5, 20.0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250, 255, 260, 265, 270, 275, 280, 285, 290, 295, 300, 305, 310, 315, 320, 325, 330, 335, 340, 345, 350, 355, 360, 365, 370, 375, 380, 385, 390, 395, 400, 410, 420, 425, 430, 440, 441, 450, 460, 470, 475, 480, 490, 500, 510, 520, 525, 530, 540, 550, 560, 570, 575, 580, 590, 600, 610, 620, 625, 630, 640, 650, 660, 670, 675, 680, 690, 700, 710, 720, 725, 730, 740, 750, 760, 770, 775, 780, 790, 800, 810, 820, 825, 830, 840, 850, 860, 870, 875, 880, 890, 900, 910, 920, 925, 930, 940, 950, 960, 970, 975, 980, 990, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400, 3500, 3600, 3700, 3800, 3900, 4000, 4100, 4200, 4300, 4400, 4500, 4600, 4700, 4800, 4900, 5000, 6000, 7000, 8000, 9000, 10000 nanograms (ng), micrograms (mcg), milligrams (mg), or grams of an LtaS inhibitor, or any range derivable therein.
Alternatively, embodiments may involve providing or administering to the patient or to cells or tissue of the patient about, at least about, or at most about 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7. 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0, 18.5, 19.0. 19.5, 20.0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250, 255, 260, 265, 270, 275, 280, 285, 290, 295, 300, 305, 310, 315, 320, 325, 330, 335, 340, 345, 350, 355, 360, 365, 370, 375, 380, 385, 390, 395, 400, 410, 420, 425, 430, 440, 441, 450, 460, 470, 475, 480, 490, 500, 510, 520, 525, 530, 540, 550, 560, 570, 575, 580, 590, 600, 610, 620, 625, 630, 640, 650, 660, 670, 675, 680, 690, 700, 710, 720, 725, 730, 740, 750, 760, 770, 775, 780, 790, 800, 810, 820, 825, 830, 840, 850, 860, 870, 875, 880, 890, 900, 910, 920, 925, 930, 940, 950, 960, 970, 975, 980, 990, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400, 3500, 3600, 3700, 3800, 3900, 4000, 4100, 4200, 4300, 4400, 4500, 4600, 4700, 4800, 4900, 5000, 6000, 7000, 8000, 9000, 10000 nanograms (ng), micrograms (mcg), milligrams (mg), or grams of an LtaS inhibitor that comprises a compound of any of formula I through XII, or a pharmaceutically acceptable salt thereof, or any range derivable therein, in one dose or collectively in multiple doses. In some embodiments, the composition comprises between about 0.1 ng and about 2.0 g of an LtaS inhibitor.
Alternatively, the composition may have a concentration of LtaS inhibitor that comprises a compound of any of formula I through XII, or a pharmaceutically acceptable salt thereof, that is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7. 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0, 18.5, 19.0. 19.5, 20.0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250, 255, 260, 265, 270, 275, 280, 285, 290, 295, 300, 305, 310, 315, 320, 325, 330, 335, 340, 345, 350, 355, 360, 365, 370, 375, 380, 385, 390, 395, 400, 410, 420, 425, 430, 440, 441, 450, 460, 470, 475, 480, 490, 500, 510, 520, 525, 530, 540, 550, 560, 570, 575, 580, 590, 600, 610, 620, 625, 630, 640, 650, 660, 670, 675, 680, 690, 700, 710, 720, 725, 730, 740, 750, 760, 770, 775, 780, 790, 800, 810, 820, 825, 830, 840, 850, 860, 870, 875, 880, 890, 900, 910, 920, 925, 930, 940, 950, 960, 970, 975, 980, 990, 1000 μg/ml or mg/ml, or any range derivable therein.
If a liquid, gel, or semi-solid composition, the volume of the composition that is administered to the patient may be about, at least about, or at most about 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7. 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0, 18.5, 19.0. 19.5, 20.0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100 microliters (μl) or milliliters (ml ), or any range derivable therein. In certain embodiments, the patient is administered up to about 10 ml of the composition.
The amount of an LtaS inhibitor compound of any of formula I through XII, or a pharmaceutically acceptable salt thereof, that is administered or taken by the patient may be based on the patient's weight (in kilograms). Therefore, in some embodiments, the patient is administered or takes a dose or multiple doses amounting to about, at least about, or at most about 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7. 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0, 18.5, 19.0. 19.5, 20.0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250, 255, 260, 265, 270, 275, 280, 285, 290, 295, 300, 305, 310, 315, 320, 325, 330, 335, 340, 345, 350, 355, 360, 365, 370, 375, 380, 385, 390, 395, 400, 410, 420, 425, 430, 440, 441, 450, 460, 470, 475, 480, 490, 500, 510, 520, 525, 530, 540, 550, 560, 570, 575, 580, 590, 600, 610, 620, 625, 630, 640, 650, 660, 670, 675, 680, 690, 700, 710, 720, 725, 730, 740, 750, 760, 770, 775, 780, 790, 800, 810, 820, 825, 830, 840, 850, 860, 870, 875, 880, 890, 900, 910, 920, 925, 930, 940, 950, 960, 970, 975, 980, 990, 1000 μg/kilogram (kg) or mg/kg, or any range derivable therein.
The composition may be administered to (or taken by) the patient 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more times, or any range derivable therein, and they may be administered every 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 hours, or 1, 2, 3, 4, 5, 6, 7 days, or 1, 2, 3, 4, 5 weeks, or 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 months, or any range derivable therein. It is specifically contemplated that the composition may be administered once daily, twice daily, three times daily, four times daily, five times daily, or six times daily (or any range derivable therein) and/or as needed to the patient. Alternatively, the composition may be administered every 2, 4, 6, 8, 12 or 24 hours (or any range derivable therein) to or by the patient. In some embodiments, the patient is administered the composition for a certain period of time or with a certain number of doses after experiencing symptoms of a pathogenic bacterial infection.
In a further aspect the patient can be at risk for Staphylococcus infection. In another embodiment the patient can be at risk for Streptococcus infection. In additional embodiments the patient is at risk for a pathogenic bacterial infection, including infection by a Gram-positive bacteria. In still further aspects, the patient is at risk for pneumonia.
Certain embodiments are directed to methods where the patient is immune deficient, is immune-compromised, is hospitalized, is undergoing an invasive medical procedure, is infected with influenza virus or is on a respirator.
In still a further aspect the patient has a Staphylococcus infection, which includes but is not limited to pneumonia, sepsis, bacteremia, corneal infection, skin infection, infection of the central nervous system, or toxic shock syndrome.
In certain aspects the methods can further comprise the step of monitoring the patient for a Gram-positive bacterial infection within a week of first administering an LtaS inhibitor that comprises a compound of any of formula I through XII, or a pharmaceutically acceptable salt thereof.
Other embodiments of the invention are discussed throughout this application. Any embodiment discussed with respect to one aspect of the invention applies to other aspects of the invention as well and vice versa. The embodiments in the Example section are understood to be embodiments of the invention that are applicable to all aspects of the invention.
The terms “inhibiting,” “reducing,” or “prevention,” or any variation of these terms, when used in the claims and/or the specification includes any measurable decrease or complete inhibition to achieve a desired result.
The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.”
It is contemplated that any embodiment discussed herein can be implemented with respect to any method or composition of the invention, and vice versa. Furthermore, compositions and kits of the invention can be used to achieve methods of the invention.
Throughout this application, the term “about” is used to indicate that a value includes the standard deviation of error for the device or method being employed to determine the value.
The use of the term “or” in the claims is used to mean “and/or” unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and/or.” It is also contemplated that anything listed using the term “or” may also be specifically excluded.
As used in this specification and claim(s), the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.
Other objects, features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating specific embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein.
Many Gram-positive bacteria incorporate zwitterionic lipoteichoic acid (LTA) into their cell wall. This polymer was first identified as the heterophile antigen of pneumococcus (Goebel et al. 1943) and its structure was elucidated by Baddiley (Baddiley 1968). Clearly, LTA plays an important role during host infection, and it has been recognized for a long time that LTA triggers innate immune responses and is a TLR ligand (Morath et al. 2005). However, its physiological function is not well understood perhaps because the genetic disruption of LTA biosynthesis could not be achieved until recently (Grundling & Schneewind, PNAS 2007 and Grundling & Schneewind, J. Bacteriol. 2007). Thus, LTA has been proposed to be broadly important for scavenging Mg2+ ion and targeting autolysins in the bacterial envelope, a function that is essential for the separation of dividing cells (Lambert et al. 1977 and Cleveland et al. 1975). LTA purified from Staphylococcus aureus and other species is composed of a polymer of glycerol phosphate linked to glycolipid, which provides for LTA anchoring in bacterial membranes (Baddiley 1968, Coley et al. 1972, Reichman & Grundling 2011, and Fischer 1990). The glycerol moieties can be modified at the 2′OH position with D-alanyl esters or N-acetylglucosamine (Nehaus & Baddiley 2003). These modifications are important for escape from innate immune defenses such as host antimicrobial peptides and they contribute to the integrity of the overall cell envelope by limiting the activity of autolysins (Nehaus & Baddiley 2003). The genes responsible for modification at the 2′OH position of polyglycerol have been identified and shown to be dispensable both for growth and LTA synthesis (Nehaus & Baddiley 2003). The genes involved in the assembly of the membrane anchor moiety for LTA have also been identified. In S. aureus for example, this moiety is composed of β-gentiobiosyldiacylglycerol[glucosyl-(1→6)-glucosyl-(1→3)-diacylglycerol(G1c2-DAG)] (Duckworth et al, 1975). Three enzymatic steps are required for the synthesis of G1c2-DAG and involve the enzymes PgcA (α-phosphoglucomutase), GtaB (UTP:α-glucose-1-phosphate uridyl transferase) and YpfP (glycosyl-transferase) (Grundling & Schneewind, J. Bacteriol. 2007, Jorasch et al. 2000, and Kiriukhin et al. 2001). Following its synthesis in the inner leaflet of the plasma membrane, the G1c2-DAG glycolipid is moved across the membrane by LtaA a member of the major facilitator super-family of proteins (Grundling & Schneewind, J. Bacteriol. 2007). Glycolipid anchor mutants (ltaA, ypfP, pgcA and gtaB) lead to morphological alterations, including increase in cell size and aberrant cell shapes (Grundling & Schneewind, J. Bacteriol. 2007, Kiriukhin et al. 2001, Grundling et al. 2006) but they continue to multiply. In these mutants, the glycerol phosphate polymer remains tethered to the membrane by a terminal DAG residue, instead of Glc2-DAG (Grundling & Schneewind, J. Bacteriol. 2007 and Kiriukhin et al. 2001). The last steps of LTA synthesis include the polymerization of polyglycerol phosphate and its transfer to G1c2-DAG (Koch et al. 1984). Gründling and Schneewind showed that in S. aureus both steps are catalyzed by a polytopic membrane protein with a large extracellular domain annotated in the Pfam database as a sulfatase domain (pfam00884) (Grundling & Schneewind, PNAS 2007). The corresponding gene was named lipoteichoic acid synthase (ltaS). Genetic depletion or loss of ltaS were found to result in severe cell division defects in S. aureus, such phenotypes being exacerbated at higher temperatures (Grundling & Schneewind, PNAS 2007 and Oku et al. 2009). The characterization of proteins with pfam00884 domain in other Gram-positive bacteria confirmed that these sulfatases are indeed responsible for the polymerization and membrane tethering of glycerol phosphates (Baddiley 1968, Coley et al. 1972, Reichman & Grundling 2011). Importantly, ltaS mutants exhibit reduced viability, increased cell size and altered envelope morphology in all organisms where they have been examined (Wormann et al. 2011, Webb et al. 2009, Schirner et al. 2009, Garufi et al. 2012 and Corrigan et al. 2011).
Under physiological conditions, growth of S. aureus, B. anthracis, L. monocytogenes or B. subitilis cannot occur without ltaS expression and LTA synthesis (Grundling & Schneewind, PNAS 2007, Wormann et al. 2011, Webb et al. 2009, Schirner et al. 2009, Garufi et al. 2012). LtaS, a polytopic membrane protein with a C-terminal catalytic domain, is located on bacterial surfaces but absent from human or animal tissues. Thus, LtaS and LTA synthesis meet the key criteria for the development of new antibiotics (Grundling & Schneewind, PNAS 2007 and Projan 2004). Therefore, embodiments described herein target LtaS and the LTA synthesis pathway. In certain embodiments, the LTA synthesis pathway is directly targeted and affected so as to inhibit a Gram-positive bacteria that uses LtaS and/or the LTA synthesis pathway.
Method and compositions include treatments for a disease or condition caused by a Gram-positive bacteria that employs the LTA synthesis pathway. An LtaS inhibitor that comprises a compound of any of formula I through XII, or a pharmaceutically acceptable salt thereof, can be given to treat a person infected with or exposed to Gram-positive bacteria or suspected of having been exposed to Gram-positive bacteria or at risk of developing a Gram-positive bacteria infection. Methods may be employed with respect to individuals who have tested positive for exposure to Gram-positive bacteria or who are deemed to be at risk for infection based on possible exposure.
In particular, there are methods of treatment for a Gram-positive bacterial infection, particularly infections associated with antibiotic-resistant Gram-positive bacteria. Moreover, methods concern treating any condition or disease that is caused by, perpetuated by, or promoted by a Gram-positive bacteria infection. Prevention and treatment methods concern inhibiting the bacteria, such as its growth, lifespan, toxicity, reproducibility, tolerance to antibiotics, etc.
In some embodiments, the treatment is administered in conjunction with Gram-positive bacteria antigens or antibodies that bind Gram-positive bacteria and/or their proteins and/or carbohydrates. Furthermore, in some examples, treatment comprises administration of other agents commonly used against bacterial infection, such as one or more antibiotics.
The compositions and related methods, particularly administration of an LtaS inhibitor that comprises a compound of any of formula I through XII, or a pharmaceutically acceptable salt thereof, or a compound that inhibits LTA or LtaS, may also be used in combination with the administration of traditional therapies. These include, but are not limited to, the administration of vaccines; anti-bacterial antibodies; or antibiotics such as streptomycin, ciprofloxacin, doxycycline, gentamycin, chloramphenicol, trimethoprim, sulfamethoxazole, ampicillin, tetracycline or various combinations of antibiotics.
In one aspect, it is contemplated that an LtaS inhibitor that comprises a compound of any of formula I through XII, or a pharmaceutically acceptable salt thereof, is used in conjunction with other antibacterial treatment. Alternatively, the therapy may precede or follow the other agent treatment by intervals ranging from minutes to weeks. In embodiments where the other agents and/or a proteins or polynucleotides are administered separately, one would generally ensure that a significant period of time did not expire between the time of each delivery, such that the agent and antigenic composition would still be able to exert an advantageously combined effect on the subject. In such instances, it is contemplated that one may administer both modalities within about 12-24 h of each other or within about 6-12 h of each other. In some situations, it may be desirable to extend the time period for administration significantly, where several days (2, 3, 4, 5, 6 or 7) to several weeks (1, 2, 3, 4, 5, 6, 7 or 8) lapse between the respective administrations.
Various combinations may be employed, for example antibiotic therapy is “A” and the LtaS inhibitor is “B”:
Administration of the compositions of the present invention to a patient/subject will follow general protocols for the administration of such compounds, taking into account the toxicity, if any, of the composition, or other compositions described herein. It is expected that the treatment cycles would be repeated as necessary. It also is contemplated that various standard therapies, such as hydration, may be applied in combination with the described therapy.
1. LtaS Inhibitors
In some embodiments, pharmaceutical compositions are administered to a subject. Different aspects involve administering an effective amount of a composition to a subject. In some embodiments, a composition comprising an LtaS inhibitor may be administered to the subject or patient to protect against or treat infection by one or more staphylococcus pathogens. Additionally, such compounds can be administered in combination with an antibiotic or another standard antibacterial therapy. Such compositions will generally be dissolved or dispersed in a pharmaceutically acceptable carrier or aqueous medium.
The active compounds or APIs described herein can be formulated for parenteral administration, e.g., formulated for injection via the intravenous, intramuscular, sub-cutaneous, or even intraperitoneal routes. The preparation of an aqueous composition that contains a compound or compounds that inhibit LtaS activity will be known to those of skill in the art in light of the present disclosure. Typically, such compositions can be prepared as injectables, either as liquid solutions or suspensions; solid forms suitable for use to prepare solutions or suspensions upon the addition of a liquid prior to injection can also be prepared; and, the preparations can also be emulsified. In addition to the compounds formulated for parenteral administration, other pharmaceutically acceptable forms include, e.g., aerosolizable, inhalable, or instillable formulations; tablets or other solids for oral administration; time release capsules; creams; lotions; mouthwashes; and the like. The preparation of an such formulations will be known to those of skill in the art in light of the present disclosure.
The pharmaceutical forms suitable for injectable use include sterile aqueous solutions or dispersions; formulations including sesame oil, peanut oil, or aqueous propylene glycol; and sterile powders for the extemporaneous preparation of sterile injectable solutions or dispersions. In all cases the form must be sterile and must be fluid to the extent that it may be easily injected. It also should be stable under the conditions of manufacture and storage and must be preserved against the contaminating action of microorganisms, such as bacteria and fungi. In certain embodiments the active ingredient is combined with a liquid for intravenous administration.
The carrier also can be a solvent or dispersion medium containing, e.g., water, ethanol, polyol (for example, glycerol, propylene glycol, and liquid polyethylene glycol, and the like), suitable mixtures thereof, and vegetable oils. The proper fluidity can be maintained, for example, by the use of a coating, such as lecithin, by the maintenance of the required particle size in the case of dispersion, and by the use of surfactants. The prevention of the action of microorganisms can be brought about by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, thimerosal, and the like. In many cases, it will be preferable to include isotonic agents, for example, sugars or sodium chloride. Prolonged absorption of the injectable compositions can be brought about by the use in the compositions of agents delaying absorption, for example, aluminum monostearate and gelatin.
Sterile injectable solutions are prepared by incorporating the active compounds in the required amount in the appropriate solvent with various of the other ingredients enumerated above, as required, followed by filtered sterilization. Generally, dispersions are prepared by incorporating the various sterilized active ingredients into a sterile vehicle that contains the basic dispersion medium and the required other ingredients from those enumerated above. In the case of sterile powders for the preparation of sterile injectable solutions, methods of preparation are, e.g., vacuum-drying and freeze-drying techniques, which yield a powder of the active ingredient, plus any additional desired ingredient from a previously sterile-filtered solution thereof.
As used herein, the term “pharmaceutically acceptable” refers to those compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgment, suitable for contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem complications commensurate with a reasonable benefit/risk ratio. The term “pharmaceutically acceptable carrier,” means a pharmaceutically acceptable material, composition or vehicle, such as a liquid or solid filler, diluent, excipient, solvent or encapsulating material, involved in carrying or transporting a chemical agent.
Some variation in dosage will necessarily occur depending on the condition of the subject. The person responsible for administration will, in any event, determine the appropriate dose for the individual subject. An effective amount of therapeutic or prophylactic composition is determined based on the intended goal. The term “unit dose” or “dosage” refers to physically discrete units suitable for use in a subject, each unit containing a predetermined quantity of the composition calculated to produce the desired responses discussed above in association with its administration, i.e., the appropriate route and regimen. The quantity to be administered, both according to number of treatments and unit dose, depends on the effects desired. Precise amounts of the composition also depend on the judgment of the practitioner and are peculiar to each individual. Factors affecting dose include physical and clinical state of the subject, route of administration, intended goal of treatment (alleviation of symptoms versus cure), and potency, stability, and toxicity of the particular composition.
Upon formulation, solutions will be administered in a manner compatible with the dosage formulation and in such amount as is therapeutically or prophylactically effective. The formulations are easily administered in a variety of dosage forms, such as the type of injectable solutions described above.
Typically, for a human adult (weighing approximately 70 kilograms), from about 0.1 mg to about 3000 mg (including all values and ranges there between), or from about 5 mg to about 1000 mg (including all values and ranges there between), or from about 10 mg to about 100 mg (including all values and ranges there between), of a compound are administered. It is understood that these dosage ranges are by way of example only, and that administration can be adjusted depending on the factors known to the skilled artisan.
2. In Vitro, Ex Vivo, or In Vivo Administration
As used herein, the term in vitro administration refers to manipulations performed on cells removed from or outside of a subject, including, but not limited to cells in culture. The term ex vivo administration refers to cells which have been manipulated in vitro, and are subsequently administered to a subject. The term in vivo administration includes all manipulations performed within a subject. In certain aspects of the present invention, the compositions may be administered either in vitro, ex vivo, or in vivo.
3. Antibodies and Passive Immunization
Another aspect is the administration of other therapies or vaccines in conjunction with an LtaS inhibitor. Methods of administering immunoglobulins directed at bacterial antigens to a recipient to prevent a staphylococcal infection can be considered a passive vaccine. Another aspect includes the use of active vaccines against staphylococcal infection in conjunction with LtaS inhibitors. Certain therapeutic methods include the administration of a therapeutic immunoglobulin or an antigen to stimulate or induce production of an immune response in a subject. A method of preparing an immunoglobulin for use in prevention or treatment of staphylococcal infection comprises the steps of immunizing a recipient or donor with a vaccine and isolating immunoglobulin from the recipient or donor. In certain aspect an immunoglobulin can bind to a cell surface protein, a toxin or any other component of the bacterium that is surface exposed, including, but not limited to lipoproteins and carbohydrate constituents of the bacterial cell wall. In other aspects an antibody may bind to a bacterial antigen and inhibit some necessary bacterial function. A pharmaceutical composition comprising an immunoglobulin, with or without an LtaS inhibitor, and a pharmaceutically acceptable carrier can be used in the manufacture of a medicament for the treatment or prevention of staphylococcal disease. A method for treatment or prevention of staphylococcal infection comprising a step of administering to a patient an effective amount of the pharmaceutical preparation of the invention is a further aspect.
The antibodies can be isolated to the extent desired by well known techniques such as affinity chromatography (Harlow and Lane, 1988). Antibodies can include antiserum preparations from a variety of commonly used animals, e.g. goats, primates, donkeys, swine, horses, guinea pigs, rats or man.
Any immunoglobulin, whether directed at any bacterial antigen and used in accordance with the present invention can include whole antibodies, antibody fragments or subfragments. Antibodies can be whole immunoglobulins of any class (e.g., IgG, IgM, IgA, IgD or IgE), chimeric antibodies or hybrid antibodies with dual specificity to two or more antigens of the invention. They may also be fragments (e.g., F(ab′)2, Fab′, Fab, Fv and the like) including hybrid fragments. An immunoglobulin also includes natural, synthetic, or genetically engineered proteins that act like an antibody by binding to specific antigens to form a complex.
A vaccine can be administered to a recipient who then acts as a source of immunoglobulin, produced in response to challenge from the specific vaccine. A subject thus treated would donate plasma from which hyperimmune globulin would be obtained via conventional plasma fractionation methodology. The hyperimmune globulin would be administered to another subject in order to impart resistance against or treat staphylococcal infection. Hyperimmune globulins are particularly useful for treatment or prevention of staphylococcal disease in infants, immune compromised individuals, or where treatment is required and there is no time for the individual to produce antibodies in response to vaccination.
When used in the context of a chemical group, “hydrogen” means —H; “hydroxy” means —OH; “oxo” means ═O; “halo” means independently —F, —Cl, —Br or —I; “amino” means —NH2 (see below for definitions of groups containing the term amino, e.g., alkylamino); “hydroxyamino” means —NHOH; “nitro” means —NO2; imino means ═NH (see below for definitions of groups containing the term imino, e.g., alkylimino); “cyano” means —CN; “azido” means —N3; in a monovalent context “phosphate” means —OP(O)(OH)2 or a deprotonated form thereof; in a divalent context “phosphate” means —OP(O)(OH)O— or a deprotonated form thereof; “mercapto” means —SH; “thio” means ═S; “thioether” means —S—; “sulfonamido” means —NHS(O)2— (see below for definitions of groups containing the term sulfonamido, e.g., alkylsulfonamido); “sulfonyl” means —S(O)2— (see below for definitions of groups containing the term sulfonyl, e.g., alkylsulfonyl); “sulfinyl” means —S(O)— (see below for definitions of groups containing the term sulfinyl, e.g., alkylsulfinyl); and “silyl” means —SiH3 (see below for definitions of group(s) containing the term silyl, e.g., alkylsilyl).
The symbol “—” means a single bond, “═” means a double bond, and “” means triple bond. The symbol “” represents a single bond or a double bond. The symbol “”, when drawn perpendicularly across a bond indicates a point of attachment of the group. It is noted that the point of attachment is typically only identified in this manner for larger groups in order to assist the reader in rapidly and unambiguously identifying a point of attachment. The symbol “” means a single bond where the group attached to the thick end of the wedge is “out of the page.” The symbol “” means a single bond where the group attached to the thick end of the wedge is “into the page”. The symbol “” means a single bond where the conformation is unknown (e.g., either R or S), the geometry is unknown (e.g., either E or Z) or the compound is present as mixture of conformation or geometries (e.g., a 50%/50% mixture).
When a group “R” is depicted as a “floating group” on a ring system, for example, in the formula:
then R may replace any hydrogen atom attached to any of the ring atoms, including a depicted, implied, or expressly defined hydrogen, so long as a stable structure is formed.
When a group “R” is depicted as a “floating group” on a fused ring system, as for example in the formula:
then R may replace any hydrogen attached to any of the ring atoms of either of the fused rings unless specified otherwise. Replaceable hydrogens include depicted hydrogens (e.g., the hydrogen attached to the nitrogen in the formula above), implied hydrogens (e.g., a hydrogen of the formula above that is not shown but understood to be present), expressly defined hydrogens, and optional hydrogens whose presence depends on the identity of a ring atom (e.g., a hydrogen attached to group X, when X equals —CH—), so long as a stable structure is formed. In the example depicted, R may reside on either the 5-membered or the 6-membered ring of the fused ring system. In the formula above, the subscript letter “y” immediately following the group “R” enclosed in parentheses, represents a numeric variable. Unless specified otherwise, this variable can be 0, 1, 2, or any integer greater than 2, only limited by the maximum number of replaceable hydrogen atoms of the ring or ring system.
When y is 2 and “(R)y” is depicted as a floating group on a ring system having one or more ring atoms having two replaceable hydrogens, e.g., a saturated ring carbon, as for example in the formula:
then each of the two R groups can reside on the same or a different ring atom. For example, when R is methyl and both R groups are attached to the same ring atom, a geminal dimethyl group results. Where specifically provided for, two R groups may be taken together to form a divalent group, such as one of the divalent groups further defined below. When such a divalent group is attached to the same ring atom, a spirocyclic ring structure will result.
In the case of a double-bonded R group (e.g., oxo, imino, thio, alkylidene, etc.), any pair of implicit or explicit hydrogen atoms attached to one ring atom can be replaced by the R group. This concept is exemplified below:
represents
For the groups below, the following parenthetical subscripts further define the groups as follows: “(Cn)” defines the exact number (n) of carbon atoms in the group. “(C≦n)” defines the maximum number (n) of carbon atoms that can be in the group, with the minimum number of carbon atoms in such at least one, but otherwise as small as possible for the group in question, e.g., it is understood that the minimum number of carbon atoms in the group “alkenyl(C≦8)” is two. For example, “alkoxy(C≦10)” designates those alkoxy groups having from 1 to 10 carbon atoms (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, or any range derivable therein (e.g., 3 to 10 carbon atoms). (Cn-n′) defines both the minimum (n) and maximum number (n′) of carbon atoms in the group. Similarly, “alkyl(C2-10)” designates those alkyl groups having from 2 to 10 carbon atoms (e.g., 2, 3, 4, 5, 6, 7, 8, 9, or 10, or any range derivable therein.
The term “alkyl” when used without the “substituted” modifier refers to a non-aromatic monovalent group with a saturated carbon atom as the point of attachment, a linear or branched, cyclo, cyclic or acyclic structure, no carbon-carbon double or triple bonds, and no atoms other than carbon and hydrogen. The groups, —CH3(Me), —CH2CH3(Et), —CH2CH2CH3(n-Pr), —CH(CH3)2(iso-Pr), —CH(CH2)2(cyclopropyl), —CH2CH2CH2CH3(n-Bu), —CH(CH3)CH2CH3(sec-butyl), —CH2CH(CH3)2(iso-butyl), —C(CH3)3(tert-butyl), —CH2C(CH3)3(neo-pentyl), cyclobutyl, cyclopentyl, cyclohexyl, and cyclohexylmethyl are non-limiting examples of alkyl groups. The term “substituted alkyl” refers to a non-aromatic monovalent group with a saturated carbon atom as the point of attachment, a linear or branched, cyclo, cyclic or acyclic structure, no carbon-carbon double or triple bonds, and at least one atom independently selected from the group consisting of N, O, F, Cl, Br, I, Si, P, and S. The following groups are non-limiting examples of substituted alkyl groups: —CH2OH, —CH2Cl, —CH2Br, —CH2SH, —CF3, —CH2CN, —CH2C(O)H, —CH2C(O)OH, —CH2C(O)OCH3, —CH2C(O)NH2, —CH2C(O)NHCH3, —CH2C(O)CH3, —CH2OCH3, —CH2OCH2CF3, —CH2OC(O)CH3, —CH2NH2, —CH2NHCH3, —CH2N(CH3)2, —CH2CH2Cl, —CH2CH2OH, —CH2CF3, —CH2CH2OC(O)CH3, —CH2CH2NHCO2C(CH3)3, and —CH2Si(CH3)3.
The term “alkanediyl” when used without the “substituted” modifier refers to a non-aromatic divalent group, wherein the alkanediyl group is attached with two σ-bonds, with one or two saturated carbon atom(s) as the point(s) of attachment, a linear or branched, cyclo, cyclic or acyclic structure, no carbon-carbon double or triple bonds, and no atoms other than carbon and hydrogen. The groups, —CH2—(methylene), —CH2CH2—, —CH2C(CH3)2CH2—, CH2CH2CH2—, and
are non-limiting examples of alkanediyl groups. The term “substituted alkanediyl” refers to a non-aromatic monovalent group, wherein the alkynediyl group is attached with two σ-bonds, with one or two saturated carbon atom(s) as the point(s) of attachment, a linear or branched, cyclo, cyclic or acyclic structure, no carbon-carbon double or triple bonds, and at least one atom independently selected from the group consisting of N, O, F, Cl, Br, I, Si, P, and S. The following groups are non-limiting examples of substituted alkanediyl groups: —CH(F)—, —CF2—, —CH(Cl)—, —CH(OH)—, —CH(OCH3)—, and —CH2CH(Cl)—.
The term “alkenyl” when used without the “substituted” modifier refers to a monovalent group with a nonaromatic carbon atom as the point of attachment, a linear or branched, cyclo, cyclic or acyclic structure, at least one nonaromatic carbon-carbon double bond, no carbon-carbon triple bonds, and no atoms other than carbon and hydrogen. Non-limiting examples of alkenyl groups include: —CH═CH2(vinyl), —CH═CHCH3, —CH═CHCH2CH3, —CH2CH═CH2(allyl), —CH2CH═CHCH3, and —CH═CH—C6H5. The term “substituted alkenyl” refers to a monovalent group with a nonaromatic carbon atom as the point of attachment, at least one nonaromatic carbon-carbon double bond, no carbon-carbon triple bonds, a linear or branched, cyclo, cyclic or acyclic structure, and at least one atom independently selected from the group consisting of N, O, F, Cl, Br, I, Si, P, and S. The groups, —CH═CHF, —CH═CHCl and —CH═CHBr, are non-limiting examples of substituted alkenyl groups.
The term “alkenediyl” when used without the “substituted” modifier refers to a non-aromatic divalent group, wherein the alkenediyl group is attached with two σ-bonds, with two carbon atoms as points of attachment, a linear or branched, cyclo, cyclic or acyclic structure, at least one nonaromatic carbon-carbon double bond, no carbon-carbon triple bonds, and no atoms other than carbon and hydrogen. The groups, —CH═CH—, —CH═C(CH3)CH2—, —CH═CHCH2—, and
are non-limiting examples of alkenediyl groups. The term “substituted alkenediyl” refers to a non-aromatic divalent group, wherein the alkenediyl group is attached with two σ-bonds, with two carbon atoms as points of attachment, a linear or branched, cyclo, cyclic or acyclic structure, at least one nonaromatic carbon-carbon double bond, no carbon-carbon triple bonds, and at least one atom independently selected from the group consisting of N, O, F, Cl, Br, I, Si, P, and S. The following groups are non-limiting examples of substituted alkenediyl groups: —CF═CH—, —C(OH)═CH—, and —CH2CH═C(Cl)—.
The term “alkynyl” when used without the “substituted” modifier refers to a monovalent group with a nonaromatic carbon atom as the point of attachment, a linear or branched, cyclo, cyclic or acyclic structure, at least one carbon-carbon triple bond, and no atoms other than carbon and hydrogen. The groups, —C≡CH, —C≡CCH3, —C≡CC6H5 and —CH2C≡CCH3, are non-limiting examples of alkynyl groups. The term “substituted alkynyl” refers to a monovalent group with a nonaromatic carbon atom as the point of attachment and at least one carbon-carbon triple bond, a linear or branched, cyclo, cyclic or acyclic structure, and at least one atom independently selected from the group consisting of N, O, F, Cl, Br, I, Si, P, and S. The group, —C≡CSi(CH3)3, is a non-limiting example of a substituted alkynyl group.
The term “alkynediyl” when used without the “substituted” modifier refers to a non-aromatic divalent group, wherein the alkynediyl group is attached with two σ-bonds, with two carbon atoms as points of attachment, a linear or branched, cyclo, cyclic or acyclic structure, at least one carbon-carbon triple bond, and no atoms other than carbon and hydrogen. The groups, —C≡C—, —C≡CCH2—, and —C≡CCH(CH3)— are non-limiting examples of alkynediyl groups. The term “substituted alkynediyl” refers to a non-aromatic divalent group, wherein the alkynediyl group is attached with two σ-bonds, with two carbon atoms as points of attachment, a linear or branched, cyclo, cyclic or acyclic structure, at least one carbon-carbon triple bond, and at least one atom independently selected from the group consisting of N, O, F, Cl, Br, I, Si, P, and S. The groups —C≡CCFH— and —C≡CHCH(Cl)— are non-limiting examples of substituted alkynediyl groups.
The term “aryl” when used without the “substituted” modifier refers to a monovalent group with an aromatic carbon atom as the point of attachment, said carbon atom forming part of one or more six-membered aromatic ring structure(s) wherein the ring atoms are all carbon, and wherein the monovalent group consists of no atoms other than carbon and hydrogen. Non-limiting examples of aryl groups include phenyl (Ph), methylphenyl, (dimethyl)phenyl, —C6H4CH2CH3(ethylphenyl), —C6H4CH2CH2CH3(propylphenyl), C6H4CH(CH3)2, C6H4CH(CH2)2, —C6H3(CH3)CH2CH3(methylethylphenyl), —C6H4CH═CH2(vinylphenyl), —C6H4CH═CHCH3, —C6H4C≡CH, —C6H4C≡CCH3, naphthyl, and the monovalent group derived from biphenyl. The term “substituted aryl” refers to a monovalent group with an aromatic carbon atom as the point of attachment, said carbon atom forming part of one or more six-membered aromatic ring structure(s) wherein the ring atoms are all carbon, and wherein the monovalent group further has at least one atom independently selected from the group consisting of N, O, F, Cl, Br, I, Si, P, and S. Non-limiting examples of substituted aryl groups include the groups: —C6H4F, —C6H4Cl, —C6H4Br, —C6H4I, —C6H4OH, —C6H4OCH3, —C6H4OCH2CH3, —C6H4OC(O)CH3, —C6H4NH2, —C6H4NHCH3, —C6H4N(CH3)2, —C6H4CH2OH, —C6H4CH2OC(O)CH3, —C6H4CH2NH2, —C6H4CF3, —C6H4CN, —C6H4CHO, —C6H4CHO, —C6H4C(O)CH3, —C6H4C(O)C6H5, —C6H4CO2H, —C6H4CO2CH3, —C6H4CONH2, —C6H4CONHCH3, and —C6H4CON(CH3)2.
The term “arenediyl” when used without the “substituted” modifier refers to a divalent group, wherein the arenediyl group is attached with two σ-bonds, with two aromatic carbon atoms as points of attachment, said carbon atoms forming part of one or more six-membered aromatic ring structure(s) wherein the ring atoms are all carbon, and wherein the monovalent group consists of no atoms other than carbon and hydrogen. Non-limiting examples of arenediyl groups include:
The term “substituted arenediyl” refers to a divalent group, wherein the arenediyl group is attached with two σ-bonds, with two aromatic carbon atoms as points of attachment, said carbon atoms forming part of one or more six-membered aromatic rings structure(s), wherein the ring atoms are carbon, and wherein the divalent group further has at least one atom independently selected from the group consisting of N, O, F, Cl, Br, I, Si, P, and S.
The term “aralkyl” when used without the “substituted” modifier refers to the monovalent group—alkanediyl—aryl, in which the terms alkanediyl and aryl are each used in a manner consistent with the definitions provided above. Non-limiting examples of aralkyls are: phenylmethyl (benzyl, Bn), 1-phenyl-ethyl, 2-phenyl-ethyl, indenyl and 2,3-dihydroindenyl, provided that indenyl and 2,3-dihydro-indenyl are only examples of aralkyl in so far as the point of attachment in each case is one of the saturated carbon atoms. When the term “aralkyl” is used with the “substituted” modifier, either one or both the alkanediyl and the aryl is substituted. Non-limiting examples of substituted aralkyls are: (3-chlorophenyl)-methyl, 2-oxo-2-phenyl-ethyl(phenylcarbonylmethyl), 2-chloro-2-phenyl-ethyl, chromanyl where the point of attachment is one of the saturated carbon atoms, and tetrahydroquinolinyl where the point of attachment is one of the saturated atoms.
The term “heteroaryl” when used without the “substituted” modifier refers to a monovalent group with an aromatic carbon atom or nitrogen atom as the point of attachment, said carbon atom or nitrogen atom forming part of an aromatic ring structure wherein at least one of the ring atoms is nitrogen, oxygen or sulfur, and wherein the monovalent group consists of no atoms other than carbon, hydrogen, aromatic nitrogen, aromatic oxygen and aromatic sulfur. Non-limiting examples of aryl groups include acridinyl, furanyl, imidazoimidazolyl, imidazopyrazolyl, imidazopyridinyl, imidazopyrimidinyl, indolyl, indazolinyl, methylpyridyl, oxazolyl, phenylimidazolyl, pyridyl, pyrrolyl, pyrimidyl, pyrazinyl, quinolyl, quinazolyl, quinoxalinyl, tetrahydroquinolinyl, thienyl, triazinyl, pyrrolopyridinyl, pyrrolopyrimidinyl, pyrrolopyrazinyl, pyrrolotriazinyl, pyrroloimidazolyl, chromenyl (where the point of attachment is one of the aromatic atoms), and chromanyl (where the point of attachment is one of the aromatic atoms). The term “substituted heteroaryl” refers to a monovalent group with an aromatic carbon atom or nitrogen atom as the point of attachment, said carbon atom or nitrogen atom forming part of an aromatic ring structure wherein at least one of the ring atoms is nitrogen, oxygen or sulfur, and wherein the monovalent group further has at least one atom independently selected from the group consisting of non-aromatic nitrogen, non-aromatic oxygen, non aromatic sulfur F, Cl, Br, I, Si, and P.
The term “heteroarenediyl” when used without the “substituted” modifier refers to a divalent group, wherein the heteroarenediyl group is attached with two σ-bonds, with two atoms, aromatic carbon atom and/or aromatic nitrogen, as the point of attachment, said carbon atom or nitrogen atom forming part of one or more aromatic ring structure(s) wherein at least one of the ring atoms is nitrogen, oxygen or sulfur, and wherein the divalent group consists of no atoms other than carbon, hydrogen, aromatic nitrogen, aromatic oxygen and aromatic sulfur. Non-limiting examples of heteroarenediyl groups include:
The term “substituted heteroarenediyl” refers to a divalent group, wherein the heteroarenediyl group is attached with two σ-bonds, with an aromatic carbon atom or nitrogen atom as points of attachment, said carbon atom or nitrogen atom forming part of one or more six-membered aromatic ring structure(s), wherein at least one of the ring atoms is nitrogen, oxygen or sulfur, and wherein the divalent group further has at least one atom independently selected from the group consisting of non-aromatic nitrogen, non-aromatic oxygen, non aromatic sulfur F, Cl, Br, I, Si, and P.
The term “heteroaralkyl” when used without the “substituted” modifier refers to the monovalent group—alkanediyl—heteroaryl, in which the terms alkanediyl and heteroaryl are each used in a manner consistent with the definitions provided above. Non-limiting examples of aralkyls are: pyridylmethyl, and thienylmethyl. When the term “heteroaralkyl” is used with the “substituted” modifier, either one or both the alkanediyl and the heteroaryl is substituted.
The term “acyl” when used without the “substituted” modifier refers to a monovalent group with a carbon atom of a carbonyl group as the point of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, further having no additional atoms that are not carbon or hydrogen, beyond the oxygen atom of the carbonyl group. The groups, —CHO, —C(O)CH3(acetyl, Ac), —C(O)CH2CH3, —C(O)CH2CH2CH3, —C(O)CH(CH3)2, —C(O)CH(CH2)2, —C(O)C6H5, —C(O)C6H4CH3, —C(O)C6H4CH2CH3, —COC6H3(CH3)2, and —C(O)CH2C6H5, are non-limiting examples of acyl groups. The term “acyl” therefore encompasses, but is not limited to groups sometimes referred to as “alkyl carbonyl” and “aryl carbonyl” groups. The term “substituted acyl” refers to a monovalent group with a carbon atom of a carbonyl group as the point of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, further having at least one atom, in addition to the oxygen of the carbonyl group, independently selected from the group consisting of N, O, F, Cl, Br, I, Si, P, and S. The groups, —C(O)CH2CF3, —CO2H (carboxyl), —CO2CH3(methylcarboxyl), —CO2CH2CH3, —CO2CH2CH2CH3, —CO2C6H5, —CO2CH(CH3)2, —CO2CH(CH2)2, —C(O)NH2(carbamoyl), —C(O)NHCH3, —C(O)NHCH2CH3, —CONHCH(CH3)2, —CONHCH(CH2)2, —CON(CH3)2, —CONHCH2CF3, —CO-pyridyl, —CO-imidazoyl, and —C(O)N3, are non-limiting examples of substituted acyl groups. The term “substituted acyl” encompasses, but is not limited to, “heteroaryl carbonyl” groups.
The term “alkylidene” when used without the “substituted” modifier refers to the divalent group ═CRR', wherein the alkylidene group is attached with one σ-bond and one πbond, in which R and R′ are independently hydrogen, alkyl, or R and R′ are taken together to represent alkanediyl. Non-limiting examples of alkylidene groups include: ═CH2, ═CH(CH2CH3), and ═C(CH3)2. The term “substituted alkylidene” refers to the group ═CRR', wherein the alkylidene group is attached with one σ-bond and one 90-bond, in which R and R′ are independently hydrogen, alkyl, substituted alkyl, or R and R′ are taken together to represent a substituted alkanediyl, provided that either one of R and R′ is a substituted alkyl or R and R′ are taken together to represent a substituted alkanediyl.
The term “alkoxy” when used without the “substituted” modifier refers to the group —OR, in which R is an alkyl, as that term is defined above. Non-limiting examples of alkoxy groups include: —OCH3, —OCH2CH3, —OCH2CH2CH3, —OCH(CH3)2, —OCH(CH2)2, —O-cyclopentyl, and —O-cyclohexyl. The term “substituted alkoxy” refers to the group —OR, in which R is a substituted alkyl, as that term is defined above. For example, —OCH2CF3 is a substituted alkoxy group.
The term “alkoxydiyl” when used without the “substituted” modifier refers to a non-aromatic divalent group, wherein the alkoxydiyl group is attached with two σ-bonds, with (a) two saturated carbon atoms as points of attachment, (b) one saturated carbon atom and one oxygen atom as points of attachment, or (c) two oxygen atoms as points of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, no carbon-carbon double or triple bonds in the group's backbone, further having no backbone atoms other than carbon or oxygen and having at least one of each of these atoms in the group's backbone, and no side chains comprising groups other than hydrogen or alkyl. The groups, —O—CH2CH2—, —CH2—O—CH2CH2—, —O—CH2CH2—O— and —O—CH2—O— are non-limiting examples of alkoxydiyl groups. The term “substituted alkanyloxydiyl” refers to a divalent group that is attached with two σ-bonds, with (a) two saturated carbon atoms as points of attachment, (b) one saturated carbon atom and one oxygen atom as points of attachment, or (c) two oxygen atoms as points of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, no carbon-carbon double or triple bonds, and at least one atom independently selected from the group consisting of N, F, Cl, Br, I, Si, P, and S, or having additional oxygen atoms beyond those in the group's backbone. The following groups are non-limiting example of a substituted alkoxydiyl groups: —O—CH2C(OH)H—O— and —O—CH2C(Cl)H—O—.
The terms “alkenyloxy”, “alkynyloxy”, “aryloxy”, “aralkoxy”, “heteroaryloxy”, “heteroaralkoxy” and “acyloxy”, when used without the “substituted” modifier, refers to groups, defined as —OR, in which R is alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl and acyl, respectively, as those terms are defined above. When any of the terms alkenyloxy, alkynyloxy, aryloxy, aralkyloxy and acyloxy is modified by “substituted,” it refers to the group —OR, in which R is substituted alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl and acyl, respectively.
The term “alkenyloxydiyl” when used without the “substituted” modifier refers to a divalent group that is nonaromatic prior to attachment, wherein the alkenyloxydiyl group is attached with two π-bonds, which may become aromatic upon attachment, with (a) two carbon atoms as points of attachment, (b) one carbon atom and one oxygen atom as points of attachment, or (c) two oxygen atoms as points of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, at least one carbon-carbon double bond that is non-aromatic at least prior to attachment, further having no backbone atoms other than carbon or oxygen and having at least one of each of these atoms in the group's backbone, and no side chains comprising groups other than hydrogen or alkyl. The groups, —O—CH═CH—, —O—CH═CHO— and —O—CH═CHCH2— are non-limiting examples of alkenyloxydiyl groups. The term “substituted alkenyloxydiyl” refers to a divalent group that is nonaromatic prior to attachment, wherein the substituted alkenyloxydiyl group is attached with two σ-bonds, which may become aromatic upon attachment, with (a) two carbon atoms as points of attachment, (b) one carbon atom and one oxygen atom as points of attachment, or (c) two oxygen atoms as points of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, at least one carbon-carbon double bond that is non-aromatic at least prior to attachment and at least one atom independently selected from the group consisting of N, F, Cl, Br, I, Si, P, and S, or having additional oxygen atoms beyond those in the group's backbone. The following groups are non-limiting example of a substituted alkenyloxydiyl groups: —O—CH═C(OH)—O— and —O—CH═C(Cl)—O—.
The term “alkylamino” when used without the “substituted” modifier refers to the group —NHR, in which R is an alkyl, as that term is defined above. Non-limiting examples of alkylamino groups include: —NHCH3, —NHCH2CH3, —NHCH2CH2CH3, —NHCH(CH3)2, —NHCH(CH2)2, —NHCH2CH2CH2CH3, —NHCH(CH3)CH2CH3, —NHCH2CH(CH3)2, —NHC(CH3)3, —NH—cyclopentyl, and —NH—cyclohexyl. The term “substituted alkylamino” refers to the group —NHR, in which R is a substituted alkyl, as that term is defined above. For example, —NHCH2CF3 is a substituted alkylamino group.
The term “dialkylamino” when used without the “substituted” modifier refers to the group —NRR′, in which R and R′ can be the same or different alkyl groups, or R and R′ can be taken together to represent an alkanediyl having two or more saturated carbon atoms, at least two of which are attached to the nitrogen atom. Non-limiting examples of dialkylamino groups include: —NHC(CH3)3, —N(CH3)CH2CH3, —N(CH2CH3)2, N-pyrrolidinyl, and N-piperidinyl. The term “substituted dialkylamino” refers to the group —NRR′, in which R and R′ can be the same or different substituted alkyl groups, one of R or R′ is an alkyl and the other is a substituted alkyl, or R and R′ can be taken together to represent a substituted alkanediyl with two or more saturated carbon atoms, at least two of which are attached to the nitrogen atom.
The terms “alkoxyamino”, “alkenylamino”, “alkynylamino”, “arylamino”, “aralkylamino”, “heteroarylamino”, “heteroaralkylamino”, and “alkylsulfonylamino” when used without the “substituted” modifier, refers to groups, defined as —NHR, in which R is alkoxy, alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl and alkylsulfonyl, respectively, as those terms are defined above. A non-limiting example of an arylamino group is —NHC6H5. When any of the terms alkoxyamino, alkenylamino, alkynylamino, arylamino, aralkylamino, heteroarylamino, heteroaralkylamino and alkylsulfonylamino is modified by “substituted,” it refers to the group —NHR, in which R is substituted alkoxy, alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl and alkylsulfonyl, respectively.
The term “amido” (acylamino), when used without the “substituted” modifier, refers to the group —NHR, in which R is acyl, as that term is defined above. A non-limiting example of an acylamino group is —NHC(O)CH3. When the term amido is used with the “substituted” modifier, it refers to groups, defined as —NHR, in which R is substituted acyl, as that term is defined above. The groups —NHC(O)OCH3 and —NHC(O)NHCH3 are non-limiting examples of substituted amido groups.
The term “alkylaminodiyl” when used without the “substituted” modifier refers to a non-aromatic divalent group, wherein the alkylaminodiyl group is attached with two σ-bonds, with (a) two saturated carbon atoms as points of attachment, (b) one saturated carbon atom and one nitrogen atom as points of attachment, or (c) two nitrogen atoms as points of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, no double or triple bonds in the group's backbone, further having no backbone atoms other than carbon or nitrogen and having at least one of each of these atoms in the group's backbone, and no side chains comprising groups other than hydrogen or alkyl. The groups, —NH—CH2CH2—, —CH2—NH—CH2CH2—, —NH—CH2CH2—NH— and —NH—CH2—NH— are non-limiting examples of alkylaminodiyl groups. The term “substituted alkylaminodiyl” refers to a divalent group, wherein the substituted alkylaminodiyl group is attached with two σ-bonds, with (a) two saturated carbon atoms as points of attachment, (b) one saturated carbon atom and one nitrogen atom as points of attachment, or (c) two nitrogen atoms as points of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, no carbon-carbon double or triple bonds in the group's backbone, and at least one atom independently selected from the group consisting of O, F, Cl, Br, I, Si, P, and S, or having additional nitrogen atom beyond those in the group's backbone. The following groups are non-limiting example of a substituted alkylaminodiyl groups: —NH—CH2C(OH)H—NH—and —NH—CH2C(Cl)H—CH2—.
The term “alkenylaminodiyl” when used without the “substituted” modifier refers to a divalent group that is nonaromatic prior to attachment, wherein the alkenylaminodiyl group is attached with two σ-bonds, which may become aromatic upon attachment, with (a) two carbon atoms as points of attachment, (b) one carbon atom and one nitrogen atom as points of attachment, or (c) two nitrogen atoms as points of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, at least one carbon-carbon double bond or carbon-nitrogen double that is non-aromatic at least prior to attachment, further having no backbone atoms other than carbon or nitrogen, and no side chains comprising groups other than hydrogen or alkyl. The groups, —NH'CH═CH—, —NH—CH═N— and —NH—CH═CH—NH— are non-limiting examples of alkenylaminodiyl groups. The term “substituted alkenylaminodiyl” refers to a divalent group that is nonaromatic prior to attachment, wherein the substituted alkenylaminodiyl group is attached with two σ-bonds, which may become aromatic upon attachment, with (a) two carbon atoms as points of attachment, (b) one carbon atom and one nitrogen atom as points of attachment, or (c) two nitrogen atoms as points of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, at least one carbon-carbon double bond or carbon nitrogen double bond that is non-aromatic at least prior to attachment and at least one atom independently selected from the group consisting of O, F, Cl, Br, I, Si, P, and S, or having additional nitrogen atoms beyond those in the group's backbone. The following groups are non-limiting example of a substituted alkenylaminodiyl groups: —NH—CH═C(OH)—CH2— and —N═CHC(Cl)H—.
The term “alkenylaminooxydiyl” when used without the “substituted” modifier refers to a divalent group, wherein the alkenylaminooxydiyl group is attached with two σ-bonds, which may become aromatic upon attachment, with two atoms selected from the group consisting of carbon, oxygen and nitrogen as points of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, at least one carbon-carbon double bond, carbon-nitrogen double, or nitrogen-nitrogen double bond that is non-aromatic at least prior to attachment, further having no backbone atoms other than carbon nitrogen or oxygen and having at least one of each of these three atoms in the backbone, and no side chains comprising groups other than hydrogen or alkyl. The group —O—CH═N—, is a non-limiting example of an alkenylaminooxydiyl group. The term “substituted alkenylaminooxydiyl” refers to a divalent group that is attached with two π-bonds, which may become aromatic upon attachment with two atoms selected from the group consisting of carbon, oxygen and nitrogen as points of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, at least one carbon-carbon double bond or carbon nitrogen double bond that is non-aromatic at least prior to attachment and at least one atom independently selected from the group consisting of F, Cl, Br, I, Si, P, and S, or having one or more additional nitrogen and/or oxygen atoms beyond those in the group's backbone. The following groups are non-limiting example of a substituted alkenylaminooxydiyl groups: —NH—CH═C(OH)—O— and —N═CHC(Cl)H—O—.
The term “alkylimino” when used without the “substituted” modifier refers to the group ═NR, wherein the alkylimino group is attached with one σ-bond and one π-bond, in which R is an alkyl, as that term is defined above. Non-limiting examples of alkylimino groups include: ═NCH3, ═NCH2CH3 and ═N-cyclohexyl. The term “substituted alkylimino” refers to the group ═NR, wherein the alkylimino group is attached with one σ-bond and one π-bond, in which R is a substituted alkyl, as that term is defined above. For example, ═NCH2CF3 is a substituted alkylimino group.
Similarly, the terms “alkenylimino”, “alkynylimino”, “arylimino”, “aralkylimino”, “heteroarylimino”, “heteroaralkylimino” and “acylimino”, when used without the “substituted” modifier, refers to groups, defined as ═NR, wherein the alkylimino group is attached with one σ-bond and one π-bond, in which R is alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl and acyl, respectively, as those terms are defined above. When any of the terms alkenylimino, alkynylimino, arylimino, aralkylimino and acylimino is modified by “substituted,” it refers to the group ═NR, wherein the alkylimino group is attached with one σ-bond and one π-bond, in which R is substituted alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl and acyl, respectively.
The term “fluoroalkyl” when used without the “substituted” modifier refers to an alkyl, as that term is defined above, in which one or more fluorines have been substituted for hydrogens. The groups, —CH2F, —CF2H, —CF3, and —CH2CF3 are non-limiting examples of fluoroalkyl groups. The term “substituted fluoroalkyl” refers to a non-aromatic monovalent group with a saturated carbon atom as the point of attachment, a linear or branched, cyclo, cyclic or acyclic structure, at least one fluorine atom, no carbon-carbon double or triple bonds, and at least one atom independently selected from the group consisting of N, O, Cl, Br, I, Si, P, and S. The following group is a non-limiting example of a substituted fluoroalkyl: —CFHOH.
The term “alkylphosphate” when used without the “substituted” modifier refers to the group —OP(O)(OH)(OR), in which R is an alkyl, as that term is defined above. Non-limiting examples of alkylphosphate groups include: —OP(O)(OH)(OMe) and —OP(O)(OH)(OEt). The term “substituted alkylphosphate” refers to the group —OP(O)(OH)(OR), in which R is a substituted alkyl, as that term is defined above.
The term “dialkylphosphate” when used without the “substituted” modifier refers to the group —OP(O)(OR)(OR′), in which R and R′ can be the same or different alkyl groups, or R and R′ can be taken together to represent an alkanediyl having two or more saturated carbon atoms, at least two of which are attached via the oxygen atoms to the phosphorus atom. Non-limiting examples of dialkylphosphate groups include: —OP(O)(OMe)2, —OP(O)(OEt)(OMe) and —OP(O)(OEt)2. The term “substituted dialkylphosphate” refers to the group —OP(O)(OR)(OR′), in which R and R′ can be the same or different substituted alkyl groups, one of R or R′ is an alkyl and the other is a substituted alkyl, or R and R′ can be taken together to represent a substituted alkanediyl with two or more saturated carbon atoms, at least two of which are attached via the oxygen atoms to the phosphorous.
The term “alkylthio” when used without the “substituted” modifier refers to the group —SR, in which R is an alkyl, as that term is defined above. Non-limiting examples of alkylthio groups include: —SCH3, —SCH2CH3, —SCH2CH2CH3, —SCH(CH3)2, —SCH(CH2)2, —S-cyclopentyl, and —S-cyclohexyl. The term “substituted alkylthio” refers to the group —SR, in which R is a substituted alkyl, as that term is defined above. For example, —SCH2CF3 is a substituted alkylthio group.
Similarly, the terms “alkenylthio”, “alkynylthio”, “arylthio”, “aralkylthio”, “heteroarylthio”, “heteroaralkylthio”, and “acylthio”, when used without the “substituted” modifier, refers to groups, defined as —SR, in which R is alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl and acyl, respectively, as those terms are defined above. When any of the terms alkenylthio, alkynylthio, arylthio, aralkylthio, heteroarylthio, heteroaralkylthio, and acylthio is modified by “substituted,” it refers to the group —SR, in which R is substituted alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl and acyl, respectively.
The term “thioacyl” when used without the “substituted” modifier refers to a monovalent group with a carbon atom of a thiocarbonyl group as the point of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, further having no additional atoms that are not carbon or hydrogen, beyond the sulfur atom of the carbonyl group. The groups, —CHS, —C(S)CH3, —C(S)CH2CH3, —C(S)CH2CH2CH3, —C(S)CH(CH3)2, —C(S)CH(CH2)2, —C(S)C6H5, —C(S)C6H4CH3, —C(S)C6H4CH2CH3, —C(S)C6H3(CH3)2, and —C(S)CH2C6H5, are non-limiting examples of thioacyl groups. The term “thioacyl” therefore encompasses, but is not limited to, groups sometimes referred to as “alkyl thiocarbonyl” and “aryl thiocarbonyl” groups. The term “substituted thioacyl” refers to a radical with a carbon atom as the point of attachment, the carbon atom being part of a thiocarbonyl group, further having a linear or branched, cyclo, cyclic or acyclic structure, further having at least one atom, in addition to the sulfur atom of the carbonyl group, independently selected from the group consisting of N, O, F, Cl, Br, I, Si, P, and S. The groups, —C(S)CH2CF3, —C(S)O2H, —C(S)OCH3, —C(S)OCH2CH3, —C(S)OCH2CH2CH3, —C(S)OC6H5, —C(S)OCH(CH3)2, —C(S)OCH(CH2)2, —C(S)NH2, and —C(S)NHCH3, are non-limiting examples of substituted thioacyl groups. The term “substituted thioacyl” encompasses, but is not limited to, “heteroaryl thiocarbonyl” groups.
The term “alkylsulfonyl” when used without the “substituted” modifier refers to the group —S(O)2R, in which R is an alkyl, as that term is defined above. Non-limiting examples of alkylsulfonyl groups include: —S(O)2CH3, —S(O)2CH2CH3, —S(O)2CH2CH2CH3, —S(O)2CH(CH3)2, —S(O)2CH(CH2)2, —S(O)2-cyclopentyl, and —S(O)2-cyclohexyl. The term “substituted alkylsulfonyl” refers to the group —S(O)2R, in which R is a substituted alkyl, as that term is defined above. For example, —S(O)2CH2CF3 is a substituted alkylsulfonyl group.
Similarly, the terms “alkenylsulfonyl”, “alkynylsulfonyl”, “arylsulfonyl”, “aralkylsulfonyl”, “heteroarylsulfonyl”, and “heteroaralkylsulfonyl” when used without the “substituted” modifier, refers to groups, defined as —S(O)2R, in which R is alkenyl, alkynyl, aryl, aralkyl, heteroaryl, and heteroaralkyl, respectively, as those terms are defined above. When any of the terms alkenylsulfonyl, alkynylsulfonyl, arylsulfonyl, aralkylsulfonyl, heteroarylsulfonyl, and heteroaralkylsulfonyl is modified by “substituted,” it refers to the group —S(O)2R, in which R is substituted alkenyl, alkynyl, aryl, aralkyl, heteroaryl and heteroaralkyl, respectively.
The term “alkylsulfinyl” when used without the “substituted” modifier refers to the group —S(O)R, in which R is an alkyl, as that term is defined above. Non-limiting examples of alkylsulfinyl groups include: —S(O)CH3, —S(O)CH2CH3, —S(O)CH2CH2CH3, —S(O)CH(CH3)2, —S(O)CH(CH2)2, —S(O)-cyclopentyl, and —S(O)-cyclohexyl. The term “substituted alkylsulfinyl” refers to the group —S(O)R, in which R is a substituted alkyl, as that term is defined above. For example, —S(O)CH2CF3 is a substituted alkylsulfinyl group.
Similarly, the terms “alkenylsulfinyl”, “alkynylsulfinyl”, “arylsulfinyl”, “aralkylsulfinyl”, “heteroarylsulfinyl”, and “heteroaralkylsulfinyl” when used without the “substituted” modifier, refers to groups, defined as —S(O)R, in which R is alkenyl, alkynyl, aryl, aralkyl, heteroaryl, and heteroaralkyl, respectively, as those terms are defined above. When any of the terms alkenylsulfinyl, alkynylsulfinyl, arylsulfinyl, aralkylsulfinyl, heteroarylsulfinyl, and heteroaralkylsulfinyl is modified by “substituted,” it refers to the group —S(O)R, in which R is substituted alkenyl, alkynyl, aryl, aralkyl, heteroaryl and heteroaralkyl, respectively.
In addition, atoms making up the compounds of the present invention are intended to include all isotopic forms of such atoms. Isotopes, as used herein, include those atoms having the same atomic number but different mass numbers. By way of general example and without limitation, isotopes of hydrogen include tritium and deuterium, and isotopes of carbon include 13C and 14C. Similarly, it is contemplated that one or more carbon atom(s) of a compound of the present invention may be replaced by a silicon atom(s). Furthermore, it is contemplated that one or more oxygen atom(s) of a compound of the present invention may be replaced by a sulfur or selenium atom(s).
A single dashed line between two atoms indicates an optional bond. The bond may not be present at all, it may be present as a single bond, or it may be present as a double bound. If an atom is only connected to dashed lines, then the atom itself is optional. It may be present or it may not be present.
A bond shown as a combination of a solid and a dashed line indicates that the bond is either a single bond or a double bond. Thus, for example, the structure
includes the structures
As will be understood by a person of skill in the art, no one such ring atom forms part of more than one double bond.
Any undefined valency on an atom of a structure shown in this application implicitly represents a hydrogen atom bonded to the atom.
As used herein, a “chiral auxiliary” refers to a removable chiral group that is capable of influencing the stereoselectivity of a reaction. Persons of skill in the art are familiar with such compounds, and many are commercially available.
The use of the word “a” or “an,” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.”
Throughout this application, the term “about” is used to indicate that a value includes the inherent variation of error for the device, the method being employed to determine the value, or the variation that exists among the study subjects.
The terms “comprise,” “have” and “include” are open-ended linking verbs. Any forms or tenses of one or more of these verbs, such as “comprises,” “comprising,” “has,” “having,” “includes” and “including,” are also open-ended. For example, any method that “comprises,” “has” or “includes” one or more steps is not limited to possessing only those one or more steps and also covers other unlisted steps.
The term “effective,” as that term is used in the specification and/or claims, means adequate to accomplish a desired, expected, or intended result.
The term “hydrate” when used as a modifier to a compound means that the compound has less than one (e.g., hemihydrate), one (e.g., monohydrate), or more than one (e.g., dihydrate) water molecules associated with each compound molecule, such as in solid forms of the compound.
As used herein, the term “IC50” refers to an inhibitory dose which is 50% of the maximum response obtained.
An “isomer” of a first compound is a separate compound in which each molecule contains the same constituent atoms as the first compound, but where the configuration of those atoms in three dimensions differs.
As used herein, the term “patient” or “subject” refers to a living mammalian organism, such as a human, monkey, cow, sheep, goat, dog, cat, mouse, rat, guinea pig, or transgenic species thereof. In certain embodiments, the patient or subject is a primate. Non-limiting examples of human subjects are adults, juveniles, infants and fetuses.
“Pharmaceutically acceptable” means that which is useful in preparing a pharmaceutical composition that is generally safe, non-toxic and neither biologically nor otherwise undesirable and includes that which is acceptable for veterinary use as well as human pharmaceutical use.
“Pharmaceutically acceptable salts” means salts of compounds of the present invention which are pharmaceutically acceptable, as defined above, and which possess the desired pharmacological activity. Such salts include acid addition salts formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like; or with organic acids such as 1,2-ethanedisulfonic acid, 2-hydroxyethanesulfonic acid, 2-naphthalenesulfonic acid, 3-phenylpropionic acid, 4,4′-methylenebis(3-hydroxy-2-ene-1-carboxylic acid), 4-methylbicyclo[2.2.2]oct-2-ene-1-carboxylic acid, acetic acid, aliphatic mono- and dicarboxylic acids, aliphatic sulfuric acids, aromatic sulfuric acids, benzenesulfonic acid, benzoic acid, camphorsulfonic acid, carbonic acid, cinnamic acid, citric acid, cyclopentanepropionic acid, ethanesulfonic acid, fumaric acid, glucoheptonic acid, gluconic acid, glutamic acid, glycolic acid, heptanoic acid, hexanoic acid, hydroxynaphthoic acid, lactic acid, laurylsulfuric acid, maleic acid, malic acid, malonic acid, mandelic acid, methanesulfonic acid, muconic acid, o-(4-hydroxybenzoyl)benzoic acid, oxalic acid, p-chlorobenzenesulfonic acid, phenyl-substituted alkanoic acids, propionic acid, p-toluenesulfonic acid, pyruvic acid, salicylic acid, stearic acid, succinic acid, tartaric acid, tertiarybutylacetic acid, trimethylacetic acid, and the like. Pharmaceutically acceptable salts also include base addition salts which may be formed when acidic protons present are capable of reacting with inorganic or organic bases. Acceptable inorganic bases include sodium hydroxide, sodium carbonate, potassium hydroxide, aluminum hydroxide and calcium hydroxide. Acceptable organic bases include ethanolamine, diethanolamine, triethanolamine, tromethamine, N-methylglucamine and the like. It should be recognized that the particular anion or cation forming a part of any salt of this invention is not critical, so long as the salt, as a whole, is pharmacologically acceptable. Additional examples of pharmaceutically acceptable salts and their methods of preparation and use are presented in Handbook of Pharmaceutical Salts: Properties, and Use (2002).
As used herein, “predominantly one enantiomer” means that a compound contains at least about 85% of one enantiomer, or more preferably at least about 90% of one enantiomer, or even more preferably at least about 95% of one enantiomer, or most preferably at least about 99% of one enantiomer. Similarly, the phrase “substantially free from other optical isomers” means that the composition contains at most about 15% of another enantiomer or diastereomer, more preferably at most about 10% of another enantiomer or diastereomer, even more preferably at most about 5% of another enantiomer or diastereomer, and most preferably at most about 1% of another enantiomer or diastereomer.
“Prevention” or “preventing” includes: (1) inhibiting the onset of a Gram-positive infection or infection-causing disease in a subject or patient which may be at risk and/or predisposed to the infection or disease but does not yet experience or display any or all of the pathology or symptomatology of such, and/or (2) slowing the onset of the pathology or symptomatology of an infection or disease in a subject or patient which may be at risk and/or predisposed to the infection or disease but does not yet experience or display any or all of the pathology or symptomatology of it.
“Prodrug” means a compound that is convertible in vivo metabolically into an inhibitor according to embodiments discussed herein. The prodrug itself may or may not also have activity with respect to a given target protein. For example, a compound comprising a hydroxy group may be administered as an ester that is converted by hydrolysis in vivo to the hydroxy compound. Suitable esters that may be converted in vivo into hydroxy compounds include acetates, citrates, lactates, phosphates, tartrates, malonates, oxalates, salicylates, propionates, succinates, fumarates, maleates, methylene-bis-β-hydroxynaphthoate, gentisates, isethionates, di-p-toluoyltartrates, methanesulfonates, ethanesulfonates, benzenesulfonates, p-toluenesulfonates, cyclohexylsulfamates, quinates, esters of amino acids, and the like. Similarly, a compound comprising an amine group may be administered as an amide that is converted by hydrolysis in vivo to the amine compound.
A “repeat unit” is the simplest structural entity of certain materials, for example, frameworks and/or polymers, whether organic, inorganic or metal-organic. In the case of a polymer chain, repeat units are linked together successively along the chain, like the beads of a necklace. For example, in polyethylene, —[—CH2CH2—]n—, the repeat unit is —CH2CH2—. The subscript “n” denotes the degree of polymerisation, that is, the number of repeat units linked together. When the value for “n” is left undefined, it simply designates repetition of the formula within the brackets as well as the polymeric nature of the material. The concept of a repeat unit applies equally to where the connectivity between the repeat units extends three dimensionally, such as in metal organic frameworks, cross-linked polymers, thermosetting polymers, etc.
The term “saturated” when referring to an atom means that the atom is connected to other atoms only by means of single bonds.
A “stereoisomer” or “optical isomer” is an isomer of a given compound in which the same atoms are bonded to the same other atoms, but where the configuration of those atoms in three dimensions differs. “Enantiomers” are stereoisomers of a given compound that are mirror images of each other, like left and right hands. “Diastereomers” are stereoisomers of a given compound that are not enantiomers.
It is contemplated that for any stereocenter or axis of chirality for which stereochemistry has not been defined, that stereocenter or axis of chirality can be present in its R form, S form, or as a mixture of the R and S forms, including racemic and non-racemic mixtures. Compounds employed in methods of the invention may contain one or more asymmetrically-substituted carbon or nitrogen atoms, and may be isolated in optically active or racemic form. Thus, all chiral, diastereomeric, racemic form, epimeric form, and all geometric isomeric forms of a structure are intended, unless the specific stereochemistry or isomeric form is specifically indicated. Compounds may occur as racemates and racemic mixtures, single enantiomers, diastereomeric mixtures and individual diastereomers. In some embodiments, a single diastereomer is obtained. The chiral centers of the compounds of the present invention can have the S- or the R-configuration, as defined by the IUPAC 1974 Recommendations. Compounds may be of the D- or L- form, for example. It is well known in the art how to prepare and isolate such optically active forms. For example, mixtures of stereoisomers may be separated by standard techniques including, but not limited to, resolution of racemic form, normal, reverse-phase, and chiral chromatography, preferential salt formation, recrystallization, and the like, or by chiral synthesis either from chiral starting materials or by deliberate synthesis of target chiral centers.
“Substituent convertible to hydrogen in vivo” means any group that is convertible to a hydrogen atom by enzymological or chemical means including, but not limited to, hydrolysis and hydrogenolysis. Examples include hydrolyzable groups, such as acyl groups, groups having an oxycarbonyl group, amino acid residues, peptide residues, o-nitrophenylsulfenyl, trimethylsilyl, tetrahydro-pyranyl, diphenylphosphinyl, and the like. Examples of acyl groups include formyl, acetyl, trifluoroacetyl, and the like. Examples of groups having an oxycarbonyl group include ethoxycarbonyl, tert-butoxycarbonyl (—C(O)OC(CH3)3), benzyloxycarbonyl, p-methoxybenzyloxycarbonyl, vinyloxycarbonyl, β-(p-toluenesulfonyl)ethoxycarbonyl, and the like. Suitable amino acid residues include, but are not limited to, residues of Gly (glycine), Ala (alanine), Arg (arginine), Asn (asparagine), Asp (aspartic acid), Cys (cysteine), Glu (glutamic acid), His (histidine), Ile (isoleucine), Leu (leucine), Lys (lysine), Met (methionine), Phe (phenylalanine), Pro (proline), Ser (serine), Thr (threonine), Trp (tryptophan), Tyr (tyrosine), Val (valine), Nva (norvaline), Hse (homoserine), 4-Hyp (4-hydroxyproline), 5-Hyl (5-hydroxylysine), Orn (ornithine) and β-Ala. Examples of suitable amino acid residues also include amino acid residues that are protected with a protecting group. Examples of suitable protecting groups include those typically employed in peptide synthesis, including acyl groups (such as formyl and acetyl), arylmethyloxycarbonyl groups (such as benzyloxycarbonyl and p-nitrobenzyloxycarbonyl), tert-butoxycarbonyl groups (—C(O)OC(CH3)3), and the like. Suitable peptide residues include peptide residues comprising two to five, and optionally amino acid residues. The residues of these amino acids or peptides can be present in stereochemical configurations of the D-form, the L-form or mixtures thereof. In addition, the amino acid or peptide residue may have an asymmetric carbon atom. Examples of suitable amino acid residues having an asymmetric carbon atom include residues of Ala, Leu, Phe, Trp, Nva, Val, Met, Ser, Lys, Thr and Tyr. Peptide residues having an asymmetric carbon atom include peptide residues having one or more constituent amino acid residues having an asymmetric carbon atom. Examples of suitable amino acid protecting groups include those typically employed in peptide synthesis, including acyl groups (such as formyl and acetyl), arylmethyloxycarbonyl groups (such as benzyloxycarbonyl and p-nitrobenzyloxycarbonyl), tert-butoxycarbonyl groups (—C(O)OC(CH3)3), and the like. Other examples of substituents “convertible to hydrogen in vivo” include reductively eliminable hydrogenolyzable groups. Examples of suitable reductively eliminable hydrogenolyzable groups include, but are not limited to, arylsulfonyl groups (such as o-toluenesulfonyl); methyl groups substituted with phenyl or benzyloxy (such as benzyl, trityl and benzyloxymethyl); arylmethoxycarbonyl groups (such as benzyloxycarbonyl and o-methoxy-benzyloxycarbonyl); and haloethoxycarbonyl groups (such as β,β,β-trichloroethoxycarbonyl and (β-iodoethoxycarbonyl).
“Therapeutically effective amount” or “pharmaceutically effective amount” means that amount which, when administered to a subject or patient for treating the infection or a disease or condition caused by the infection, is sufficient to effect such treatment.
“Treatment” or “treating” includes (1) inhibiting a Gram-positive infection or a disease or condition that is caused by the Gram-positive infection in a subject or patient experiencing or displaying the pathology or symptomatology of the infection, disease, or condition (e.g., arresting further development of the pathology and/or symptomatology), (2) ameliorating the infection, disease, or condition in a subject or patient that is experiencing or displaying the pathology or symptomatology of the disease (e.g., reversing the pathology and/or symptomatology), and/or (3) effecting any measurable decrease in the infection, disease, or condition in a subject or patient that is experiencing or displaying the relevant pathology or symptomatology.
As used herein, the term “water soluble” means that the compound dissolves in water at least to the extent of 0.010 mole/liter or is classified as soluble according to literature precedence.
The above definitions supersede any conflicting definition in any of the reference that is incorporated by reference herein. The fact that certain terms are defined, however, should not be considered as indicative that any term that is undefined is indefinite. Rather, all terms used are believed to describe the invention in terms such that one of ordinary skill can appreciate the scope and practice the present invention.
The following examples are given for the purpose of illustrating various embodiments of the invention and are not meant to limit the present invention in any fashion. One skilled in the art will appreciate readily that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those objects, ends and advantages inherent herein. The present examples, along with the methods described herein are presently representative of certain embodiments, are provided as an example, and are not intended as limitations on the scope of the invention. Changes therein and other uses which are encompassed within the spirit of the invention as defined by the scope of the claims will occur to those skilled in the art.
The antibiotic sensitive strain S. aureus RN4220 was used to screen for small molecule growth inhibitors in a high throughput-screening assay using 384-well microplates. Cation-adjusted Hinton Mueller II broth supplemented with 0.005% Tween-80 was inoculated with a single colony of S. aureus RN4220. Following overnight incubation, the culture was diluted 1:100 in fresh medium and incubation was continued until the bacterial suspension reached an optical density at 600 nm (OD600) of 0.6 corresponding to a bacterial titer of 5×108 colony forming units (CFU) per ml. An aliquot of this culture was diluted 1:400 with fresh medium and stored on ice until it could be dispensed in 384-well plates. Small-scale experiments were conducted to determine the Z′-factor (1-[(3SD−)+(3SD+)/(Ave−)−(Ave+)]) used commonly for quality assessment of raw data sets generated in high-throughput screening. In this formula, (SD+/−) and (Ave+/−) represent standard deviation and average of positive and negative controls. Four 384-well plates were loaded with 25 μl medium per well. Half the wells were supplemented with 4 nmol chloramphenicol each (positive controls), whereas the remaining wells were not (negative controls). Each well was inoculated with 25 μl aliquot of the culture kept on ice (approximately 3.125×104 CFU). The OD600 in each well was recorded after 20 hours incubation. Z′ values varied between 0.72 and 0.84. For the high throughput screen (HTS) experiment, microplates were preloaded with medium and then processed by a Seiko pin-transfer robot with a Caliper Twister II robotic arm. The robot was programmed to add 2-3 nmol chemical library compound solubilized in 0.3 μl DMSO to each assay well. In additon to assay wells, every microplate included 16 positive and 16 negative control wells supplemented or not with 4 nmol chloramphenicol, respectively. 25 μl aliquots of the starter culture kept on ice were added to both assay and control wells and microplates were incubated at 42° C. in humidified chambers (humidity>85%). After 20 hours, the OD600 was measured using a plate reader in absorbance mode. The screen was carried out in duplicate. Compounds that reduced bacterial growth by 90% or more were defined as screen positives and retested once for validation using the HTS protocol.
Bacterial cultures were grown at 37° C. to an OD600 of 0.6 and diluted 100-fold with ice-cold medium. The growth medium was Brain Heart Infusion (BHI) broth for staphylococci, enterococci, and bacilli. Clostridium perfringes was grown in BHI supplemented with 0.5% yeast extract and 0.1% L-cysteine in a nitrogen atmosphere. E. coli BL21 was cultured in cation-adjusted Mueller-Hinton II medium supplemented with 0.005% Tween-80. Growth inhibition was carried out in triplicate using 96-well microplates. Assay plates were preloaded with 100-μl aliquots of two-fold dilution series of compound prepared in growth medium and 10 μl of ice-cold starter culture was added to every assay well. The plates were incubated at 37° C. for 18-22 hours and the density of cultures was recorded with a plate reader. Normalized OD600 measurements were used to derive the minimum inhibitory concentration (MIC) for growth for each compound. Software package GraphPad Prism 5 was used to calculate the 50% growth inhibitory concentration (IC50) values.
Human promyelocytic leukemia HL-60 cells (American Type Culture Collection number CCL-240) were maintained in RPMI 1640(CellGro) supplemented with 10% heat-inactivated fetal bovine serum (HyClone), 2mM L-glutamine, penicillin (50 units×ml−1) and streptomycin (50 μg×ml−1). Cell cultures were grown at 37° C. in 5% CO2 until cell density reached 106 cell×ml−1. Cells were washed three times and suspended in Dulbecco's modified eagle medium (DMEM, Invitrogen). Microtiter plates (96 wells) were loaded with 104 cells per well suspended in 100 μl DMEM containing increasing concentrations of compound. The plates were incubated for 4 hours at 37° C. in 5% CO2. The cytotoxicity of compounds was assessed by measuring the activity of lactate dehydrogenase (LDH) released from cells that were damaged during the incubation. The LDH assay was performed in triplicate using the Cytotoxicity Detection Kit according manufacturer's instructions (Roche). LDH measurements were normalized as percentage of the total LDH activity in a cell lysate.
An overnight culture of S. aureus RN4220 was diluted 100-fold in BHI medium supplemented or not with a sub-inhibitory concentration of hit compound. The cultures were incubated at 37° C. and bacterial growth was monitored over time until the control culture without compound reached an OD600 of 1.0. Aliquots of 1 ml were removed from each culture and mixed with 0.5 ml glass beads (0.1 mm diameter). Bacteria were lysed in a bead beater and glass beads were removed by centrifugation (1 min at 200×g). The supernatant was centrifuged again (10 min, 16,000×g) to sediment cell debris containing cell-associated LTA. The pellet was suspended with 0.5 M Tris-HCl (pH 8.0)/2% SDS buffer in a volume normalized according OD600 values. Samples were heat-treated at 95° C. for 30 min and cleared by centrifugation. Supernatants were separated by SDS-PAGE and analyzed by immunoblotting using a monoclonal antibody to detect LTA and polyclonal antibodies for LtaS and SrtA. Immune-reactive signals for LTA and LtaS were normalized against the envelope protein SrtA that remains unaffected by LTA synthesis inhibitors.
Bacteria were grown on solid medium and washed in water prior to fixation with 2% glutaraldehyde in phosphate buffered saline (PBS). Sample processing was performed as described earlier (Garufi et al. 2012). Examination of specimen was performed with a Fei Nova NanoSEM 200 scanning electron microscope (FEI Co., Hillsboro, Oreg., USA). The SEM was operated with an acceleration voltage of 5 kV and samples were viewed at a distance of 5 mm. Thin sectioning of samples was performed as described (Garufi et al. 2012) and images were recorded using a Tecnai F30 (Philips/FEI) transmission electron microscope (Field emission gun operating with a 300-kV accelerating voltage, using a magnification of 15,000 to 30,000×) and a high performance CCD camera with a 4 k×4 k resolution. Images were captured using Gatan DigitalMicrograph software and processed using Adobe Photoshop (Adobe, San Jose, Calif., USA). The thickness of the cell wall envelope was determined by examining at least 15 properly thin sectioned cells observed on micrographs obtained by transmission electron microscopy and as described earlier (Garufi et al. 2012). Data were plotted in Graphpad Prism 5.0 and the Student's t test (unpaired, 2-tailed) was used for statistical analyses.
Cells were fixed using 4% buffered formalin and observed. Images were obtained with a CCD Camera on a Olympus IX81 microscope using 100× or 40× objectives. The lengths of bacilli was measured directly from acquired DIC images using ImageJ, and converted to lengths in microns using reference images with an objective micrometer. The data were displayed in a box and whisker plot. The Student's t test (unpaired, 2-tailed) was used for statistical analyses.
Recombinant eLtaS and SrtA were used to examine protein interactions with a synthetic phosphatidylglycerol modified with nitro-benzoxadiazole (NBD-PG). For this study, we used 1-palmitoyl-2-{12-[7-nitro-2-1,3-benzoxadiazole-4-yl)amino]dodecanoyl]-sn-glycerol-3-[phospho-rac-(1-glycerol) purchased from Avanti Polar Lipids. eLtaS was cloned using vector pProEX (In vitrogen, Life Technologies) as described by Lu et al. (Lu et al. 2009). SrtA was purified using plasmid pHTT27 as described by Ton-That et al. (Ton-That et al. 2002). Both proteins were purified over nickel-nitrilotriacetic acid resin as described (Ton-That et al. 2002). To study the interaction with NBD-PG, size-exclusion HPLC was performed with a BioBasic SEC300 column equilibrated in a 50 mM HEPES-KOH buffer, pH 7.5 containing 10 μM MnCl2. Chromatograms were recorded by measuring absorbance at 460 nm to detect the presence of NBD-PG.
Inhibitor solution was prepared freshly prior to every injection. Briefly, a frozen stock of compound 1771 (1) was pre-warmed at 37° C. for 5 minutes and suspended into Compound buffer (20 mM HEPES-KOH, pH 7.5, 100 mM NaCl). The clinical isolate Newman was used for infection since it has been extensively characterized in our laboratory to study the therapeutic effects of small molecule inhibitors (McAdow 2011). In vitro, strain Newman displayed similar sensitivity toward compound 1771 as strain USA300. An overnight culture of strain Newman was diluted 1:100 into fresh TSB and grown until an OD600 of 0.4. Bacteria were centrifuged at 7,000×g, washed, and suspended in one-tenth volume of PBS. Six week-old female BALB/c mice (n=15) (Charles River) were injected retro-orbitally with 1×108 colony forming unit (CFU) suspension in 100 μl of PBS. Mice were monitored for survival over 10 days. Animals received either two injections of inhibitor (32 mg/kg) or Compound buffer (Mock) prior to infection and an additional six doses post-infection. Animal experiments were performed in accordance with the institutional guidelines following experimental protocol reviewed and approved by the Institutional Biosafety Committee (IBC) and the Institutional Animal Care and Use Committee (IACUC) at the Univ. of Chicago. Log-rank was performed to analyze the statistical significance by Prism (GraphPad Software, Inc.) and P values less than 0.05 were deemed significant.
S. aureus lacking the ltaS gene is unable to grow at temperatures above 37° C. (Oku et al, 2009). This phenotype was utilized to screen for candidate compounds that inhibit growth of wild type S. aureus strain RN4220 at 37° C. A growth assay amenable to HTS using 384-well microplates was developed. A single colony of S. aureus RN4220 was inoculated in cation-adjusted Hinton Mueller II broth supplemented with 0.005% Tween-80 and incubated overnight. Next day, the culture was diluted in fresh medium and incubation was continued until the optical density reached a bacterial titer equivalent to 5×108 colony forming units (CFU) per ml. Culture aliquots (containing approximately 3.125×104 CFU) were dispensed in 384-well plates containing small molecule compounds. The inhibitory activity of candidate compounds was compared to that of chloramphenicol (80 μM) or medium alone (no antibiotic; no compound). Incubation of cultures with chloramphenicol (80 μM, positive control) fully abolished growth of S. aureus strain RN4220 (100% inhibition as compared to medium alone, negative control). A screen hit was defined as a compound that reduced growth by 90% or more as compared to untreated cultures (negative control). The quality of the screen was assessed for every assay plate with the Z′-factor, a measure for data variability within the dynamic range of the assay (Zhang et al. 1999). Small molecule libraries from different vendors (Asinex, ChemBridge, ChemDiv, Enamine, LifeChemicals, Maybridge, TimTec) were tested in duplicate at the National Screening Laboratory for Regional Centers of Excellence in Biodefense and Emerging Infectious Disease (NSRB) at Harvard Medical School (Boston, Mass.). The screen included a total of 167,405 compounds and yielded 595 screen positives corresponding to a primary hit rate of 0.36% (Table 1). Hit compounds were subjected to a validation experiment whereby growth inhibition was tested once more using the 384-well plate format. 308 compounds were confirmed as screen positives displaying growth inhibition greater than 90% (Table 1). A computational analysis (World Wide Web at Molinspiration.com) of molecular properties of the 308 hit compounds (i.e. molecular weight, polar surface area, number of hydrogen bond donors and acceptors, and bond rotation) was conducted to determine violations of Lipinski's rule-of-five. The NSRB informatics group performed an analysis of promiscuous inhibitory activity and the NSRB medical chemistry group provided an evaluation on suitability for drug development. The analysis identified 116 compounds with drug-like properties that were commercially available and purchased for secondary screening experiments.
1) Growth inhibition was ≧90% using compound library stock solutions at a final concentration of approximately 40-60 μM;
2) Cytotoxicity of small molecules was measured using HL60 cells.
The 116 compounds with strong inhibitory activity were subjected to a dose-response analysis and their inhibitory attribute and cytotoxicity were assessed for specificity. To this end, growth inhibitory dose-responses were compared between S. aureus strain USA300 (MRSA) and E. coli K12 (Table 1). The overall cytotoxicity of compounds was assessed using human promyelocytic leukemia (HL-60) cells. This secondary screen revealed 43 possible candidates that specifically inhibited growth of MRSA without affecting the growth of E. coli or viability of HL-60 cells. The secondary screen identified 6 molecules that specifically inhibited growth of MRSA without affecting the growth of E coli but did affect viability of HL-60 cells (1592-E15, 1739-J18, 1775-G05, 1776-J05, 1849-L21 and 1586-O03). Sub-lethal concentrations of the 43 candidate compounds were used to examine the production of LTA in S. aureus using extracts of bacterial cultures grown with or without sub-inhibitory concentration of hit compounds. Three compounds, compound 1771, 1650-C01, and 1650-I01, were found to affect the production of LTA of S. aureus.
The formula at the top of
An overnight culture of S. aureus was diluted in the presence of increasing concentrations of compound 1771 dissolved in DMSO. For this experiment, all cultures received the same volume of DMSO containing 0, 2 or 5 μM of compound 1771 and were monitored until the OD600 of the control culture (DMSO only) reached a value of 1.0 (
Production of the glycerolphosphate polymer can be recapitulated in E. coli by expression the gene ltaSSA on a plasmid (Grundling, 2007). The growth of E. coli expressing or not ltaSSA was not affected following incubation of cultures with and without 200 μM of compound 1771 (
Whether candidate 1771 has broad-spectrum activity was investigated against several Gram-positive bacterial species that synthesize LTA. MRSA, vancomycin-resistant Enterococci (VRE), Clostridium perfringes, B. cereus and B. anthracis were selected for this study including Clostridium difficile for which an LtaS enzyme cannot be readily identified albeit that this organism also synthesizes an LTA-like molecule (Table 2). Staphylococcal strains encode one LtaS enzyme and we wondered whether antibiotic resistant strains such as MRSA USA300 might be as sensitive as the MSSA strain RN4220. A genomic analysis suggests that E. faecalis and E. faecium encode two LtaS enzymes that are related between enterococci (
S. aureus - MRSA
E. faecalis - VRE
E. faecium - VRE
C. perfringens
B. anthracis
B. anthracis
B. cereus
C. difficile
C. difficile
C. difficile
C. difficile
(1) IC50 values and 95%-confidence intervals were calculated by fitting data with variable slope sigmoidal dose-response function (GraphPad Prism 5);
2) Hill slope value of dose-response graph is >15.
The mechanism of action of compound 1771 was explored in vitro using extracellular S. aureus LtaS (eLtaS) produced in E. coli (Grundling & Schneewind, PNAS 2007 and Garufi et al. 2012). eLtaS does not encompass the full length protein but rather a domain that is exposed on the cell surface of S. aureus (Grundling & Schneewind, PNAS 2007). X-ray crystallography confirmed the predicted function of LtaS by revealing that the structure of eLtaS solved at 1.2-Å resolution adopts a sulfatase-like fold (Lu et al. 2009). The presence of glycerol-phosphate in the crystal and supporting site-directed mutagenesis experiments confirmed that an active site threonine functions as nucleophile for phosphatidylglycerol hydrolysis and formation of a covalent threonine-glycerolphosphate intermediate (Lu et al. 2009). When phosphatidylglycerol is offered to purified eLtaS, it is effectively cleaved into hydrophilic glycerol and hydrophobic phosphatide (Karatsa-Dodgson et al. 2010). A similar clone was used to produce eLtaS and following incubation of phosphatidylglycerol, the expected cleavage products, glycerol and phosphatide, were obtained. However, formation of polyglycerolphosphate, the polymer synthesized in vivo, could not be found (data not shown;
S. aureus RN4220
B. anthracis Sterne
The therapeutic impact of compound 1771 during infection was examined. First, we evaluated the half-life of compound 1771 in vivo. Animals received intraperitoneal injections with 32 mg/kg of compound. The blood of three animals was drawn 1, 6 and 12 hours following intraperitoneal injections and the compound was extracted with methanol and chloroform, separated by reverse phase HPLC and subjected to mass spectrometry (data not shown). This analysis revealed two peaks corresponding to two fragments of compound 1771, none of which retained inhibitory activity. The conversion occurred between 3 and 6 hours. To evaluate, the efficacy of compound 1771, we used a mouse model of staphylococcal sepsis. Animals received intraperitoneal injections with 32 mg/kg of compound in 12-hour intervals. Treatment was initiated 24 hours prior to challenge and terminated at 72 hours post infection. Following challenge of mice via blood stream injection of 1×108 CFU S. aureus Newman, mock treated animals died of sepsis within 24 hours (
Compound 1771 Inhibits S. aureus Growth and LTA Synthesis
S. aureus variants that cannot express ltaS are unable to grow at 37° C. (Grundling 2007). We took advantage of the temperature-sensitive phenotype and screened compound libraries at the National Screening Laboratory for the Regional Centers of Excellence in Biodefense and Emerging Infectious Disease (NSRB) for candidate compounds that inhibit growth of S. aureus at 42° C. The primary screen identified 73 compounds with greater than 90% growth inhibition (SI, Supplementary Table 1). Thirty-one compounds were subjected to secondary screening, which included dose-response analyses for growth inhibition of MRSA as well as the Gram-negative microbe Escherichia coli. Fifteen compounds specifically inhibited the growth of MRSA but not of E. coli and displayed little or no cytotoxicity when added to HL-60 cells, a human promyelocytic leukemia cell (Table 1). One of these molecules, compound 1771, was identified as an inhibitor of LTA synthesis in S. aureus as follows.
Overnight cultures of S. aureus were diluted and incubated with increasing concentrations of compound 1771 (0, 2 or 5 μM), resulting in increased reduction of growth (
Expression of LtaS from S. aureus (ltaSSA) or Bacillus anthracis (ltaS2BA) in E. coli leads to the production of 1,3-polyglycerol phosphate, as LTA synthase can utilize phosphatidylglycerol (PG) substrate even from the membrane of Gram-negative bacteria (
To examine the spectrum of antibiotic activity for compound 1771, we analyzed Gram-positive bacteria harboring polyglycerol-phosphate LTA as well as LtaS homologues (
Bacterial cultures incubated with or without sublethal concentrations of compound 1771 were examined by scanning electron microscopy (SEM) (
Thin-section transmission electron microscopy (TEM) of S. aureus treated with compound 1771 revealed the thickening and structural disorganization of the cell wall envelope (
The three dimensional structure of the extracellular catalytic domain of LtaS has been determined (Schirner 2009, Lu 2009). Overall, eLtaS assumes a sulfatase-like fold, however its active site is distinct from that of sulfatases (Lu 2009). Threonine (T300) of LtaS together with residues E255, D475 and H476 coordinate a manganese ion and assemble to form a binding pocket for glycerol-phosphate (Lu 2009). As revealed from the co-crystal structure of eLtaS with glycerol-phosphate, one oxygen atom of the phosphate group is coordinated with Mg2+, whereas the remainder of the phosphate group is stabilized by hydrogen bonding with H416 and W354. Hydroxyl side chains of glycerol-phosphate form hydrogen bonds with H347, D349 and R356 (Lu 2009). Catalysis has been proposed to involve PG docking in the active site of eLtaS to enable nucleophilic attack from the deprotonated hydroxyl of T300, generating a glycerol-phosphate-threonine intermediate and releasing diacylglycerol. The glycerol-phosphate-threonine intermediate may subsequently be resolved by the nucleophilic attack from the terminal OH group of another PG, thereby extending the LTA chain by one glycerol-phosphate moiety (Lu 2009).
Incubation of purified eLtaS with compound 1771 followed by mass spectrometry analysis of enzyme and inhibitor did not reveal the formation of an eLtaS adduct or the cleavage of compound 1771. We used size exclusion HPLC with BioBasic SEC300 column equilibrated with 20 nmol nitro-benzoxadiazole glycerol-phosphate (NBD-GP) to measure binding of enzyme to substrate. Chromatography of 2 nmol eLtaS on BioBasic SEC300 column led to the elution of enzyme.NBD-GP complex and absorbance at 460 nm (
The results in
Compound 1771 Prolongs the Survival of Mice with S. aureus Sepsis
To examine the therapeutic value of compound 1771, we evaluated its half-life in mice. Animals received a single intraperitoneal injection of 32 mg/kg compound 1771. The blood of three animals was drawn 1, 6 and 12 hours following 1771 injection and serum samples were extracted with methanol and chloroform, separated by reversed-phase HPLC and subjected to mass spectrometry. This analysis revealed two absorption peaks corresponding to cleavage fragments of compound 1771, none of which retained inhibitory activity. Full conversion of compound 1771 into its two cleavage fragments occurred between 3 and 6 hours following injection. The enzyme(s) responsible for compound 1771 cleavage are not yet known and it is not yet clear whether compound 1771 can be modified to resist cleavage whilst retaining its antibiotic activity.
To evaluate the therapeutic efficacy of compound 1771, we used a mouse model of staphylococcal sepsis (McAdow 2011). Animals received intraperitoneal injections with 32 mg/kg of compound in 12-hour intervals. Treatment was initiated 24 hours prior to challenge and terminated at 72 hours post infection. Following challenge of mice via bloodstream injection of 1×108 CFU S. aureus Newman, mock treated animals died of sepsis within 24 hours (
Selecting for S. aureus Variants with Increased Resistance to Compound 1771
The therapeutic value of many antibiotics is limited because bacteria acquire resistance via spontaneous mutations that modify the drug target (Walsh 2000). For example, streptomycin blocks ribosomal protein synthesis (Anand 1960, Jones 1944), however mutations in rpsL, the structural gene for ribosomal protein S12, alter the polypeptide to prevent antibiotic access to the ribosome (Funatsu 1972). In contrast to streptomycin-resistant mutants, which arise at frequencies <10−7 (
An overnight culture was diluted in medium supplemented with either 1% DMSO (control culture) or 1 μM compound 1650-C01 or 1650-I01. Bacterial growth was monitored until the OD600 of the control culture reached a value of 1.0 (
A comparison of the structures of all 43 MRSA inhibitors identified one compound, 1650-M01, with similarity to 1650-C01 and 1650-I01 (
Production of the glycerolphosphate polymer can be recapitulated in E. coli by expression of the ltaSSA gene on a plasmid. The growth of E. coli expressing or not ltaSSA was not affected following incubation of cultures with and without 200 μM of either compound (
Whether inhibitors 1650-C01, 1650-I01 and 1650-M01 have broad-spectrum activity was investigated against several Gram-positive bacterial species that synthesize LTA. MRSA, vancomycin-resistant Enterococci (VRE), and B. anthracis were selected for this study (Table 4). Staphylococcal strains encode one LtaS enzyme and we wondered whether antibiotic resistant strains such as MRSA USA300 might be as sensitive as the MSSA strain RN4220. A genomic analysis suggests that E. faecalis and E. faecium encode two LtaS enzymes that are related between enterococci (
S. aureus-MRSA
S. aureus-MSSA
E. faecalis-VRE
E. faecium-VRE
B. anthracis
1)IC50 values and 95%-confidence intervals were calculated by fitting data with variable slope sigmoidal dose-response function (GraphPad Prism 5)
Owing to the frequent use of antibiotics, members of the human microbiome continuously evolve drug resistance (DeLeo 2010). For MRSA, drug-resistance is associated with therapeutic failure and increased mortality of human infections (Klevens 2007, Klevens 2008). Glycopeptide (vancomycin)-resistance has transferred from enterococci to MRSA (Weigel 2003); the resulting VRSA strains are broadly antibiotic resistant and represent a global infectious threat (Tenover 2001, Li 2012). Daptomycin and linezolid have recently been licensed to address the threat of MRSA and VRSA infections (Arbeit 2004, Stevens 2002). Nevertheless, staphylococci quickly developed daptomycin- and linezolid-resistance, indicating that additional antibotics are needed to combat S. aureus infections (van Hal 2011). The crisis in antibiotic resistance applies also to other Gram-positive pathogens, including C. difficile, E. faecium, E. faecalis, S. epidermidis and Streptococcus pneumoniae (Neu 1992, Willems 2011).
LTA synthesis has been explored as a target for antibiotic therapy. Growth of S. aureus, B. anthracis, L. monocytogenes or B. subitilis cannot occur without polyglycerol-phosphate LTA synthesis and ltaS expression (Grundling 2007, Webb 2009, Schirner 2009, Wormann 2011). LtaS, the catalyst of LTA synthesis, harbors five transmembrane domains and a C-terminal catalytic domain that is found in bacteria but not in eukaryotes (Grundling 2007). The unique presence of LTA and LtaS in the envelope of bacterial species, the availability of the catalytic domain of LtaS on the bacterial surface and the requirement of LTA synthesis for bacterial growth and cell division fulfill key target features for the development of new antibiotics (Projan 2004). Compound 1771 was characterized as an LTA synthesis inhibitor, demonstrated its mechanism of action and ability to kill Gram-positive bacteria with polyglycerol-phosphate LTA. We were unable to isolate staphylococcal mutants with resistance against compound 1771, suggesting that LTA synthesis may display target attributes similar to peptidoglycan synthesis. Some Gram-positive bacteria, for example C. difficile and S. pneumoniae, synthesize LTA with distinct phosphate-polymer structures (Fischer 1997, Reid 2012), however their mechanisms of synthesis and possible inhibition by compound 1771 are not yet known. Future work must develop compound 1771 further to generate molecules that are stable in mammalian tissues and display antibiotic activity against many different bacteria. Such compounds may be useful therapeutics for human infectious diseases caused by drug-resistant Gram-positive bacteria.
The NSRB library of 167,405 compounds was screened for molecules that inhibited the >90% growth of S. aureus RN4220 in Mueller-Hinton broth II supplemented with 0.005% Tween-80 in a 384 well format by measuring the optical density at 600 nm (Z′=0.72−0.84). A 98.9% pure preparation of 2-oxo-2-[(5-phenyl-1,3,4-oxadiazol-2-yl)amino]ethylnaphtho[2,1-b]furan-1-ylacetate compound 1771) was obtained from Enamine (catalog number T5526252).
Cultures of E. coli, S. aureus, C. perfringens, E. faecalis, E. faecium, B. anthracis and B. cereus were grown in the presence or absence of inhibitor in 96-well microplates at 37° C. for 18-22 hours and monitored by measuring the optical density at 600 nm.
Bacteria grown in the presence or absence of compound 1771 were lysed in a bead beater and cell extracts subjected to Coomassie-stained SDS-PAGE or immunoblotting using a monoclonal antibody to detect LTA/polyglycerol-phosphate and polyclonal antibodies for LtaS and SrtA.
eLtaS Inhibition
Size-exclusion High Performance Liquid Chromatography (HPLC) was performed with a BioBasic SEC300 column equilibrated in a 50 mM HEPES-KOH buffer, pH 7.5 containing 10 μM MnC12. The column was pre-equilibrated with 2 nmol 1-palmitoyl-2-[12-[7-nitro-2-1,3-benzoxadiazole-4-yl)amino]dodecanoyl]-sn-glycerol-3-[phospho-rac-(1-glycerol) (Avanti Polar Lipids). Purified eLtaS and SrtA (2 nmol) were injected and chromatograms recorded by measuring absorbance at 460 nm.
Samples were examined with a Fei Nova NanoSEM 200 scanning electron microscope (FEI Co., Hillsboro, Oreg., USA) operated with an acceleration voltage of 5 kV at a distance of 5 mm. Thin sectioned samples were viewed with a Tecnai F30 (Philips/FEI) transmission electron microscope (Field emission gun operating with a 300-kV accelerating voltage, using a magnification of 15,000-30,000×) and a high performance CCD camera with 4 k×4 k resolution.
Animal experiments were performed in accordance with the institutional guidelines following experimental protocol review and approval by the Institutional Biosafety Committee (IBC) and the Institutional Animal Care and Use Committee (IACUC) at the University of Chicago. S. aureus Newman (1×108 CFU suspended in 100 μl PBS) was injected into the periorbital venous plexus of BALB/c mice (n=15) and animals were monitored for survival over 10 days. Animals received either two injections of inhibitor (32 mg/kg) or compound buffer (Mock) separated by 12 hour intervals prior to infection and an additional six doses post-infection.
Selecting for S. aureus Mutants with Increased Resistance to Compound 1771
Initial experiments sought to isolate antibiotic-resistant variants of S. aureus RNA4220 on LB agar plates with the Kirby-Bauer disk diffusion assay. Staphylococci (2.4×107 CFU) were inoculated per plate, which allowed for the isolation of streptomycin resistant variants (filter disk with 50 μmol streptomycin) but not for the isolation of compound 1771-resistant variants (filter disk with 200 μmol streptomycin). The mutation frequency for compound 1771-resistance was then analyzed with Mueller-Hinton agar plates containing a concentration gradient from 10 to 200 μM 1771. Large square plates (225 mm side length) were inoculated with 2×109 CFU S. aureus RN4220 per plate and incubated at either 37° C. or 42° C. Small, slow-growing colonies were observed only after 3-4 days of incubation. Three isolates were subjected to susceptibility testing against the 1771 inhibitor.
S. aureus RN4220
E. faecalis V583
E. faecium TX0016
1Bacterial growth in the presence of the LTA synthesis inhibitor (compound 1771) or in its absence (mock) was analyzed by scanning electron microscopy to reveal clusters of associated cocci (≧8 cells) compared to the sum of all individual cocci, diplococci or coccal clusters. Compound 1771 inhibition of S. aureus cluster formation was analyzed in multiple independent trials for statistical significance with the unpaired two-tailed Student's t-test (P = 0.0079).
Enterococcus faecium and Bacillus anthracis with compound
S. aureus
E. faecalis
E. faecium
B. anthracis
1Bacteria were grown overnight on BHI agar in the absence (mock) or presence of the LTA synthesis inhibitor (1771) and were prepared for thin-section transmission electron microscopy to measure the envelope thickness, i.e. the diameter of the cell wall in nm. The mean of 124 measurements is indicated and the standard error of the means provided in parenthesis. The differential of the diameter (Δ) was calculated by subtracting the mean of the 1771 treated bacteria from that of mock-treated controls.
2Data were analyzed with the two-tailed Student's t-test for statistical significance and P values recorded.
S. aureus strain
S. aureus RN4220 and three isolates picked from selective agar plates containing compound 1771 were compared for their susceptibility to compound 1771 in growth inhibition experiments. Observed MIC and calculated IC50 are presented.
The following references, to the extent that they provide exemplary procedural or other details supplementary to those set forth herein, are specifically incorporated herein by reference.
Emorl and Gaynes, Clin. Microbiol. Rev., 6(4):428-42, 1993.
This Application claims priority to U.S. Provisional Patent Application No. 61/691159 filed on Aug. 20, 2012 and U.S. Provisional Patent Application No. 61/752171 filed on Jan. 14, 2013, both of which are hereby incorporated by reference in their entirety.
This invention was made with government support under grant U54-AI-057153 awarded by the NIAID. The government has certain rights in the invention.
Filing Document | Filing Date | Country | Kind |
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PCT/US13/55854 | 8/20/2013 | WO | 00 |
Number | Date | Country | |
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61691159 | Aug 2012 | US | |
61752171 | Jan 2013 | US |