Claims
- 1. A compound of the formulae: ##STR15## in which R is represented by hydrogen, C.sub.1-4 alkyl, or --CF.sub.3 ; R.sub.1 and R.sub.2 are each independently represented by hydrogen, C.sub.1-4 alkyl, C.sub.5-6 cycloalkyl, C.sub.1-3 alkylphenyl in which the phenyl ring may be optionally substituted, --CF.sub.3, phenyl or substituted phenyl; M is represented by N--O--R.sub.3 or N--NH--R.sub.3, in which R.sub.3 is represented by hydrogen, C.sub.1-4 alkyl or C.sub.1-3 alkylphenyl in which the phenyl ring may be optionally substituted; A is represented by a methylene or a trimethylene bridging group, either of which may be optionally substituted with up to 2 substituents selected from the group consisting of --CF.sub.3 C.sub.1-4 alkyl, C.sub.5-6 cycloalkyl, C.sub.1-3 alkylphenyl in which the phenyl ring may be optionally substituted, phenyl, substituted phenyl; and B is represented by: ##STR16## in which Z is represented by hydrogen, C.sub.1-4 alkyl, C.sub.5-6 cycloalkyl, C.sub.2-4 trialkylamino, C.sub.1-3 alkylphenyl in which the phenyl ring may be optionally substituted, phenyl, or substituted phenyl; the pharmaceutically acceptable acid addition salts thereof; the pharmaceutically acceptable basic addition salts thereof, the optical isomers thereof; the geometric isomers thereof and tautomers thereof, with the following proviso's a) at least one the substituents represented by R, R.sub.1 and R.sub.2 must be a hydrogen atom, and b) when B is represented by a piperazine derivative then at least one of the substituents represented by an oxazolone derivative then R must be a hydrogen atom.
- 2. A compound according to claim 1, wherein A is represented by methylene.
- 3. A compound according to claim 1 wherein A is represented by trimethylene.
- 4. A compound according to claim 2 wherein R is represented by hydrogen or a C.sub.1-4 alkyl.
- 5. A compound according to claim 4 wherein R.sub.1 is represented by hydrogen or a C.sub.1-4 alkyl.
- 6. A compound according to claim 1 wherein said methylene is substituted with a C.sub.1-4 alkyl.
- 7. A compound according to claim 1 in which R.sub.1 and R.sub.2 are hydrogen.
- 8. A compound according to claim 1 in which Z is hydrogen.
- 9. A compound according to claim 1 of the formula: ##STR17##
- 10. A compound according to claim 1 of the formula: ##STR18##
- 11. A compound according to claim 1 in which said compound is 4-(2-Oxo-3-phosphonopropyl)-2-piperazine carboxylic acid.
- 12. A compound according to claim 1 in which said compound is 4(2-Oxo-3-phosphonopropyl)-2-piperazine carboxylic acid ethyl ester.
- 13. A method for the treatment of epilepsy comprising administering to a patient in need thereof an anti-epileptic amount of a compound according to claim 1.
- 14. A method for preventing ischemic/hypoxic damage to cerebral tissue comprising administering to a patient in need thereof an effective amount of a compound according to claim 1.
- 15. A method according to claim 14 in which said hypoxic/ischemic damage is due to a stroke or a cerebrovascular accident.
- 16. A method for the treatment of anxiety comprising administering an anxiolytic amount of a compound according to claim 1.
- 17. A method for producing an analgesic effect comprising administering to a patient in need thereof an analgesic amount of a compound according to claim 1.
- 18. A method for treating muscle spasms comprising administering an anti-spasmodic amount of a compound according to claim 1.
- 19. A method for antagonizing the effects of excitatory amino acids upon the NMDA receptor complex comprising administering to a patient in need thereof an NMDA antagonistic amount of a compound according to claim 1.
- 20. A pharmaceutical composition comprising a compound according to claim 1 which is present in an NMDA antagonistic amount in admixture with a pharmaceutically acceptable carrier.
Parent Case Info
This is a continuation-in-part of application Ser. No. 508,333, filed Apr. 11, 1990, which is a continuation-in-part of application Ser. No. 409,478, filed Sept. 19, 1989.
The present invention is directed to a new class of beta ketone, beta oxime and beta hydrazine phosphonate NMDA antagonists. Another aspect of the invention is directed to the treatment of epilepsy, nerve trauma such as that caused by stroke, cardiac arrest, hypoglycemia, and physical damage to either the brain or spinal cord, neurogenerative diseases, anxiety and for the relief of pain. A further aspect of the invention is directed to pharmaceutical compositions containing these NMDA antagonists.
A new class of excitatory amino acid antagonists which act at the NMDA receptor complex have been discovered which can be described by the following formulae: ##STR1## in which R is represented by hydrogen, C.sub.1-4 alkyl, or --CF.sub.3; R.sub.1 and R.sub.2 are each independently represented by hydrogen, C.sub.1-4 alkyl, cycloalkyl, alkylphenyl, --CF.sub.3, phenyl or substituted phenyl; M is represented by N--O--R.sub.3 or N--NH--R.sub.3, in which R.sub.3 is represented by hydrogen, C.sub.1-4 alkyl or alkylphenyl; A is represented by a methylene or a trimethylene bridging group, either of which may be optionally substituted with up to 2 substituents selected from the group consisting of --CF.sub.3, C.sub.1-4 alkyl, cycloalkyl, alkylphenyl, phenyl, substituted phenyl; and B is represented by one of the following substituents: in which Z is represented by hydrogen, C.sub.1-4 alkyl, cycloalkyl, trialkylamino, alkylphenyl, phenyl, or substituted phenyl; and X is represented by alkyl, alkylphenyl, or trifluoromethyl; the pharmaceutically acceptable acid addition salts thereof; the pharmaceutically acceptable basic addition salts thereof, the tautomers thereof, the optical isomers thereof, and the geometric isomers thereof; with the following proviso's: a) in Formula I, when R, R.sub.1, and R.sub.2 are hydrogen, A is an unsubstituted methylene, and B is represented by H.sub.2 N--CH--COOZ, in which Z is hydrogen; then the compound is not present as its L-isomer; b) at least one of the substituents represented by R, R.sub.1 and R.sub.2 must be a hydrogen atom; c) when B is represented by either a piperazine derivative or an .alpha.-substituted amino acid then at least one of the substituents represented by R.sub.1 and R.sub.2 must be a hydrogen atom, and; d) when B is represented by an oxazolone derivative, then R must be hydrogen.
As used in this application:
The expression "pharmaceutically acceptable acid addition salts" is intended to apply to any non-toxic organic or inorganic acid addition salt of the base compounds represented by Formulae I, Ia or any of its intermediates. Illustrative inorganic acids which form suitable salts include hydrochloric, hydrobromic, sulphuric, and phosphoric acid and acid metal salts such as sodium monohydrogen orthophosphate, and potassium hydrogen sulfate. Illustrative organic acids which form suitable salts include the mono-, di-, and tricarboxylic acids. Illustrative of such acids are for example, acetic, glycolic, lactic, pyruvic, malonic, succinic, glutaric, fumaric, malic, tartaric, citric, ascorbic, maleic, hydroxymaleic, benzoic, hydroxy-benzoic, phenylacetic, cinnamic, salicyclic, 2-phenoxy-benzoic, p-toluenesulfonic acid, and sulfonic acids such as methane sulfonic acid and 2-hydroxyethane sulfonic acid. Such salts can exist in either a hydrated or substantially anhydrous form. In general, the acid addition salts of these compounds are soluble in water and various hydrophilic organic solvents, and which in comparison to their free base forms, generally demonstrate higher melting points.
The expression "pharmaceutically acceptable basic addition salts" is intended to apply to any non-toxic organic or inorganic basic addition salts of the compounds represented by Formulae I, Ia, or any of its intermediates. Illustrative bases which form suitable salts include alkali metal or alkaline-earth metal hydroxides such as sodium, potassium, calcium, magnesium, or barium hydroxides; ammonia, and aliphatic, alicyclic, or aromatic organic amines such as methylamine, dimethylamine, trimethylamine, and picoline.
Some of the compounds of Formulae I and Ia exist as optical isomers. Any reference in this application to one of the compounds represented by Formulae I or Ia is meant to encompass either a specific optical isomer or a mixture of optical isomers (unless it is expressly excluded). The specific optical isomers can be separated and recovered by techniques known in the art such as chromatography on chiral stationary phases or resolution via chiral salt formation and subsequent separation by selective crystallization. Alternatively utilization of a specific optical isomer as the starting material will produce the corresponding isomer as the final product.
Examination of Formula I shows that the beta ketone phosphonates of Formula I will exist in a state of tautomeric equilibrium in which the carbonyl function will participate in a keto-enol equilibrium reaction. As is obvious to those skilled in the art, when the compound exists in its enol form then both R.sub.1 and R.sub.2 will not be bonded to the indicated carbon atom. Thus only those compounds in which either R.sub.1 or R.sub.2 is hydrogen will exhibit this tautomerism. This tautomerism may be depicted as follows: ##STR5##
The enol tautomer will exist as geometric isomers due to the presence of the double bond. This enol will exist as the following cis and trans isomers: ##STR6##
In those compounds of Formula I in which A is represented by a trimethylene moiety, another equilibrium reaction will be established in which the compounds undergo an intramolecular condensation to form a cyclic imine. One example of such a ketone-imine equilibrium reaction is depicted below: ##STR7##
In the compounds of Formula Ia in which M is an oxime derivative, it is possible for the oxime substituent to exist in one of two configurations, either syn or anti.
Any reference to the compounds of Formula I or Ia should be construed as encompassing the keto forms of these compounds, the enol form of these compound in either the cis or trans configuration, the cyclic imine form of these compounds, the syn or anti oxime derivative, etc. It is also intended for the claims to encompass these compounds as well.
Illustrative examples of compounds encompassed by Formula I include:
As with any class of medicinal agents, certain of the compounds of Formulae I and Ia are preferred due to their superior potency, bioavailability characteristics, etc. It is preferred for A to be represented by a methylene moiety, and for B to be represented by either a piperazine derivative or an amino acid, which may be optionally substituted at the .alpha.-position.
Illustrative examples of preferred compounds include:
The compounds of Formula I can be prepared using techniques well known in the art.
Those compounds in which B is represented by an amino acid or a derivative of an amino acid (i.e. H.sub.2 N--CH--COOZ) and R is represented by a hydrogen atom can be prepared using the methodology depicted below in Reaction Scheme I: ##STR8##
In Step A of Reaction Scheme I, an amino acid as described by Formula II in which A is as in Formula I is subjected to a protection reaction in which a benzyl carbamate protecting group (Pg) is placed on the free amine of the amino acid thereby producing the protected amino acid of Formula III. In Step B of Reaction Scheme I, the protected amino acid of Formula III is contacted with paraformaldehyde thereby further protecting the amino acid by converting it into an oxazolone derivative as described by Formula IV. In Step C, the oxazolone is contacted with thionyl chloride which introduces an acid chloride function into the molecule thereby producing the acid chloride of Formula V.
In Step D, the acid chloride of Formula V is subjected to a coupling reaction, optionally in the presence of a transition metal catalyst, with the phosphonate of Formula VI in which R.sub.1 and R.sub.2 are as in Formula I, M is represented by a suitable cation, and each Y is independently represented by a C.sub.1-4 alkyl. This coupling reaction produces the protected beta ketone phosphonate derivative of Formula VII in which A, R.sub.1, R.sub.2, and Y are as above. In Step E, a deprotection reaction is conducted which serves to remove all of the protecting groups from the beta keto phosphonate molecule. This reaction removes the benzyl carbamate protecting group, the oxazolone protecting group, and the alkyl groups represented by Y. In optional Step F, an ester function can be introduced at the phosphonic acid function of the final product of Formula I.
The proper starting material in Step A of Reaction Scheme I is an amino acid in which A is represented by the same methylene or trimethylene function as that desired in the final product of Formula I. The protection reaction of Step A can be carried out using techniques well known in the art. Typically the amino acid of Formula II is contacted with from 1 to 1.5 equivalents of benzyl chloroformate at approximately room temperature in about a 0.05 to 0.2 molar solution of sodium. hydroxide. The reactants are typically stirred together for a period of time ranging from about 1 to 3 days. The protected amino acid of Formula III can be recovered from the reaction using techniques known in the art such as extraction with an organic solvent or concentration.
The protection reaction of Step B, in which the oxazolone protecting group is placed on the protected amino acid of Formula III, can be carried out using methods known in the art. The amino acid of Formula III is typically contacted with from about 2 to 3 equivalents of paraformaldehyde in the presence of an acid catalyst such as para-toluene sulfonic acid. The catalyst is typically present in the reaction zone in a quantity of from about 1 to 3 w/w% relative to the quantity of amino acid utilized. The reactants are typically stirred together in an organic solvent such as benzene at a temperature range of from 40.degree. C. to reflux for a period of time ranging from about 1 to 4 hours.
The oxazolone of Formula IV can be recovered from the reaction using techniques known in the art such as either concentration or extraction. If desired, the protected amino acid of Formula IV can be purified by selective acid, base, and organic solvent extractions.
The next step in the reaction is to prepare the acid chloride of Formula V as is depicted in Step C. This acid chloride can be prepared using techniques known in the art. Typically the oxazolone of Formula IV is contacted with from about 3 to 4 equivalents of thionyl chloride. The reaction can be carried out neat or in a solvent such as chloroform. The reaction is allowed to proceed for a period of time ranging from 10 to 20 minutes at reflux. After the reaction is completed, the acid chloride of Formula V can be recovered from the reaction by concentration under vacuum.
In Step D of the reaction, the acid chloride of Formula V is subjected to a coupling reaction with a phosphonate as described by Formula VI. The appropriate phosphonate is one in which R.sub.1 and R.sub.2 are represented by the same substituents as that in the desired product of Formula I. The alkyl functions represented by Y in the phosphonate are not retained in the final product. The cation represented by M is typically Li or Zn. The phosphonates of Formula VI are known in the art as are methods for their preparation.
This coupling reaction can be carried out using techniques well known in the art. Typically equimolar amounts of the phosphonate and a suitable base, such as n-butyl lithium, are contacted to form a cation of the phosphonate. This is then treated with approximately a 10% mole excess of the acid chloride in the presence of a transition metal catalyst such as copper iodide. The catalyst is typically present in the reaction zone in an equivalent amount. The reactants are typically contacted at a temperature range of from about -78.degree. to room temperature for a period of time ranging from about 2 to 16 hours. The resulting protected beta ketone phosphonate derivative of Formula VII can be recovered from the reaction zone by either concentration or extraction as is known in the art. If desired, the beta ketone phosphonate can be purified by chromatographic techniques known in the art such as flash chromatography.
The deprotection reaction depicted in Step E can be carried out using techniques known in the art. This deprotection reaction serves to remove the benzyl carbamate protecting group (Pg), the oxazolone protecting group and the alkyl groups represented by Y, thereby producing some of the beta ketone phosphonates of Formula I. Typically, the protected beta ketone phosphonate derivative of Formula VII is contacted with a stoichometric amount of trimethylsilyl iodide (TMSI, about 4 equivalents) in a solvent such as methylene dichloride. The deprotection reaction is typically carried out at room temperature for a period of time ranging from about 3 to 5 hours. The quantity of trimethylsily iodide which is utilized is important. Failure to use stoichometric quantities of the TMSI will produce a compound in which not all of the protecting groups have been removed.
If Z is to be represented by a substituent other than hydrogen, then it is necessary to carry out the optional esterification of Step F. This esterification can be carried out using techniques well known in the art. Suitable esterification methods include refluxing the beta ketone phosphonate with an alcohol in the presence of an acid. This alcohol should correspond structurally to the desired ester moiety. Other methods known in the art may also be utilized.
Those compounds of Formula I in which R is represented by hydrogen and B is represented by an oxazolone: ##STR9## can also be made using techniques known in the art. These compounds can be produced using the same synthesis taught above in Reaction Scheme I, with the exception of one slight modification. The only modification is that in the deprotection reaction of Step E, the amount of TMSI that is utilized is changed. Approximately 3 equivalents of TMSI will produce a beta keto phosphonate as described by Formula I in which the benzyl carbamate protecting group and the alkyl groups represented by Y have been removed, but in which the oxazolone moiety is retained in the molecule.
Those compounds of Formula I in which B is represented by a piperazine moiety can also be prepared according to techniques known in the art. For example they can be prepared using the method taught below in Reaction Scheme III. ##STR10##
The first step of Reaction Scheme III is to conduct an N-alkylation between a piperazine derivative as described by Formula VIII in which Y is represented by a C.sub.1-4 alkyl and a halo-enol phosphonate derivative as described by Formula IX in which R.sub.1 and A are as in Formula I, E is a C.sub.1-4 alkyl or CF.sub.3 and each Y is independently represented by a C.sub.1-4 alkyl. This N-alkylation produces the enol phosphonate derivative of Formula X in which Y, E, R.sub.1 and A are as defined above. The enol phosphonate derivative of Formula X is then subjected to a hydrolysis reaction which serves to remove the protecting groups represented by Y and transforms the enol moiety into a carbonyl function. This hydrolysis can also remove the protecting group represented by E depending upon the concentration of acid that utilized. If R is to be represented by a hydrogen atom in the desired compound of Formula I, then this complete hydrolysis should be carried out. If Z is to be then the optional esterification of Step C should be carried out.
One of the starting materials is a piperazine as described by Formula VIII in which Y is represented by a C.sub.1-4 alkyl. This alkyl group will not be retained in the final product and thus its identity is immaterial. The other starting material is a halo-enol phosphonate as described by Formula IX in which each Y is independently represented by a C.sub.1-4 alkyl, E is represented by a C.sub.1-4 alkyl or CF.sub.3 and R.sub.1, and A are as in Formula I. The substituents represented by R.sub.1, and A will be retained in the final product; therefore the halo-enol phosphonate that is utilized should have the same substituent at these positions as is desired in the final product of Formula I. The alkyl groups represented by Y will not be retained in the final product and their identity is immaterial. The substituent represented by E may be retained in the final product depending on whether a partial or complete hydrolysis is carried out. If E is to be represented by either CF.sub.3 or a C.sub.1-4 alkyl then the halo-enol phosphate utilized should contain this substituent at the E position. The piperazines of Formula VIII and the halo-enol phosphonates of Formula IX are known in the art as are their method of preparation.
The N-alkylation reaction can be carried out using techniques well known in the art. Typically approximately equimolar amounts of the piperazine derivative and the halo-enol phosphonate are contacted together in a polar solvent such as water, for a period of time ranging from about 0.5 to 18 hours. The N-alkylation is typically conducted at room temperature in the presence of a base such as sodium hydroxide. The base is typically present in the quantity of from about 1 to 3 equivalents. The enol piperazine derivative of Formula X produced thereby can be recovered from the reaction zone using techniques known in the art such as extraction or concentration. If desired, the enol piperazine derivative of Formula X can be purified by chromatographic techniques known in the art such as ion exchange chromatography.
The enol piperazine of Formula X is then subjected to a hydrolytic deprotection reaction which serves to remove the protecting groups represented by Y and may remove the protecting group represented by E depending upon reaction conditions. In order to remove both protecting groups represented by Y and E, the enol piperazine derivative of Formula X is contacted with about a 6 molar solution of a mineral acid such as hydrochloric acid. This hydrolysis is conducted at a temperature range of from about 60.degree. C. to reflux for a period of time ranging from about 1 to 18 hours. Alternatively all of the protecting groups can be removed using TMSI in the manner taught in reaction Scheme I.
The partial hydrolysis in which E is not removed from the molecule is carried out by contacting the enol piperazine with a 1M molar solution of a mineral acid such as hydrochloric acid at a temperature range from 60.degree. C. to reflux for a period of time ranging from one to eight hours. Regardless of which deprotection is utilized, the desired compound of Formula I can be recovered from the reaction by either concentration or extraction. It can then be purified by chromatographic techniques such as ion exchange chromatography or by recrystallization from a solvent system such as water and alcohol.
If Z is to be represented by an ester function, then it is necessary to carry out an esterification reaction in order to place the desired substituent on the Z position. This esterification can be conducted in the same manner as the esterification reaction of Step F in Reaction Scheme I. The esterified product can also be recovered and purified in the same manner as well.
Those compounds of Formula I in which B is represented by an .alpha.-substituted amino acid (i.e. H.sub.2 N--CX--COOZ) can be prepared using the synthesis taught below in Reaction Scheme IV: ##STR11##
In Step A of Reaction Scheme IV, an alkylation reaction is conducted between a 3,6-dimethoxy-piperazine derivative as described by Formula XI in which X is as defined in Formula I and a halo-enol phosphonate derivative as previously described by Formula IX in which R.sub.1 and A are as in Formula I, each Y is independently represented by a C.sub.1-4 alkyl and E is a C.sub.1-4 alkyl or CF.sub.3. This alkylation produces the piperazine phosphonate derivative of Formula XII in which X, A, R.sub.1, E and Y are as above. In Step B, the piperazine phosphonate derivative of Formula XII is subjected to a hydrolysis which cleaves the piperazine ring, removes the alkyl groups represented by Y, and may remove the substituent represented by E depending upon the manner in which the hydrolysis is carried out. This hydrolysis produces a beta-ketone phosphonate derivative as described by Formula I in which B is represented by an .alpha.-substituted amino acid (i.e. H.sub.2 N--CX--COOZ). If Z is to be represented by an ester moiety, then it is necessary to carry out the esterification reaction of Step C.
The 3,6-dimethoxy-piperazine that is utilized as a starting material should have the same substituent at the X position as will be desired in the final product of Formula I. The halo-enol phosphonate of Formula IX that is utilized should have the same substituent at the A and R.sub.1 position as is desired in the final product of Formula I. The alkyl substituents represented by Y will not be retained in the final product and their particular identity is not critical. If E is to be represented by either CF.sub.3 or a C.sub.1-4 alkyl then the halo-enol phosphate utilized should contain this substituent at the E position. The halo-enol phosphonates of Formula IX and the 3,6-dimethoxy piperazines of Formula XII are known in the art as are their method of preparation.
The alkylation reaction depicted in Step A can be carried out using techniques well known in the art. Typically, the 3,6-dimethoxy-piperazine is first contacted with an approximately equivalent amount of a base such as N-butyl lithium. They are typically contacted at a temperature range of from -78.degree. C. to 0.degree. C. for a period of time ranging from about 0.5 to 8 hours in a solvent such as tetrahydrofuran.
The reaction zone is then warmed to a temperature of about 30.degree. C. and an approximately equimolar amount of the halo-enol phosphonate of Formula IX is added to the reaction. The reactants are then stirred together for a period of time ranging from about 1 to 18 hours. The reaction is then quenched with water and the piperazine phosphonate derivative of Formula XII is recovered from the reaction zone by either extraction or concentration. If desired, the piperazine phosphonate derivative of Formula XII can be purified by chromatographic techniques known in the art such as flash chromatography or by recrystallization from a solvent system such as ethyl acetate/hexane as is known in the art.
The next step in the reaction sequence is to subject the piperazine phosphonate derivative of Formula XII to the hydrolysis depicted in Step B. This hydrolysis reaction can be carried out using techniques known in the art. If a complete hydrolysis is desired, (i.e. R is to be H) then the piperazine phosphonate is contacted with a 0.25 to 6 molar solution of a mineral acid such as HCL. The deprotection reaction is typically carried out at a temperature range of from about 20.degree. to 100.degree. C. for a period of time ranging from 1 to 18 hours.
If a partial hydrolysis is desired, (i.e. the substituent represented by E is to be retained in the final product) then the hydrolysis is carried out for 1 to 2 hours with a 0.2 to 1M solution of HCl. The resulting beta ketone phosphonate of Formula I produced via either hydrolysis can be recovered from the reaction zone by either concentration or extraction. The beta ketone phosphonate of Formula I can then be purified in the manner taught in Step B of Reaction Scheme III.
As in the other Reaction Schemes, if Z is to be represented by an ester function then it is necessary to carry out the esterification reaction depicted in Step C.
Those compounds of Formula I which R is a non-hydrogen substituent and B is an amino acid or a derivative of an amino acid, (i.e. H.sub.2 N--CH--COOZ) can also be prepared using the methods taught immediately above in Reaction Scheme IV. The only modification to the reaction sequence is in the starting materials that are utilized. The 3,6-dimethoxy piperazine of Formula XII that is utilized should have a hydrogen atom at the X-position. Since R will be a non-hydrogen substituent, the deprotection reaction of Step B should be a partial hydrolysis.
Those compounds of Formula I in which B is represented by an .alpha.-substituted amino acid can also be prepared by carrying out an alkylation reaction between a halo-enol phosphonate as previously described by Formula IX and an imine as described by Formula XIII in below in which X is as defined in Formula I, Ph represents a phenyl ring, and Alk represents a C.sub.1-4 alkyl: ##STR12##
This alkylation reaction can be conducted in the same manner as the alkylation reaction depicted in Step A of Reaction Scheme IV. This alkylation produces an imine phosphonate as described by Formula XIV below in which R.sub.1, X and A are as defined in Formula I, and Ph and Alk are as defined above: ##STR13##
A beta ketone phosphonate of Formula I can then be produced by subjecting the imine phosphonate of Formula XIV to an acidic hydrolysis in the same manner as the deprotection reaction of Step B in Reaction Scheme IV. As in the other reaction Schemes, if Z is to be represented by an ester moiety, then an esterification reaction needs to be conducted. This esterification reaction can be conducted in the same manner as the esterification reaction in Step F of Reaction Scheme I.
The compounds of Formula Ia can also be prepared utilizing techniques known in the art. One method for preparing these compounds is disclosed below in Reaction Scheme V: ##STR14##
In Reaction Scheme V, one of the beta ketone phosphonates of Formula I is subjected to a condensation reaction with either an oxime or hydrazine derivative, as depicted by Formula XV in which M is as defined in Formula Ia. This produces one of the beta hydrazones or beta oximes of Formula Ia.
The appropriate reactants for the condensation reaction are a beta ketone phosphonate in which A, B, R.sub.1, R.sub.2 and R are represented by the same substituent as is desired in the final product and an appropriately substituted oxime or hydrazine in which M is represented by the same substituent as is desired in the final product. The condensation reaction can be carried out using techniques known in the art. Typically approximately equivalent amounts of the compound of Formula XV and the beta ketone phosphonate of Formula I are contacted in a buffered solution. Sodium acetate is one suitable buffer. The reaction is typically carried out at a temperature range of from 25 to 80.degree. C. for a period of time ranging from 1 to 24 h. The desired compound of Formula Ia can then be recovered from the reaction and purified by either gel filtration or ion exchange chromatography.
The compounds of Formulae I and Ia are excitatory amino acid antagonists. They antagonize the effects which excitatory amino acids have upon the NMDA receptor complex. They preferentially bind to the glutamate binding site located on the NMDA receptor complex. They are useful in the treatment of a number of disease states.
The compounds exhibit anti-convulsant properties and are useful in the treatment of epilepsy. They are useful in the treatment of grand mal seizures, petit mal seizures, psychomotor seizures, and autonomic seizures. One method of demonstrating their anti-epileptic properties is by the compounds ability to inhibit audiogenic convulsions in DBA/2 mice. This test can be conducted in the following manner.
Typically one group of from 6-8 male DBA/2J audiogenic susceptible mice are administered from about 0.01 .mu.g to about 100 .mu.g of the test compound. The test compound is administered intracerebrally into the lateral ventricle of the brain. A second group of mice are administered an equal volume of a saline control by the same route. Five minutes later the mice are placed individually in glass jars and are exposed to a sound stimulus of 110 decibels for 30 seconds. Each mouse is observed during the sound exposure for signs of seizure activity. The control group will have a statistically higher incidence of seizures than the group which receives the test compound.
Another method for demonstrating the anti-epileptic properties of these compounds is by their ability to inhibit the seizures that are caused by the administration of quinolinic acid. This test can be conducted in the following manner.
One group containing ten mice are administered 0.01-100 .mu.g of test compound intracerebroventricularly in a volume of 5 microliter of saline. A second control group containing an equal number of mice are administered an equal volume of saline as a control. Approximately 5 minutes later, both groups are administered 7.7 micrograms of quinolinic acid intracerebroventricularly in a volume of 5 microliters of saline. The animals are observed for 15 minutes thereafter for signs of clonic seizures. The control group will have a statistically higher rate of clonic seizures than will the test group.
The compounds of Formulae I and Ia are useful for preventing or minimizing the damage which nervous tissues contained within the CNS suffer upon exposure to either ischemic, hypoxic, or hypoglycemic conditions. Representative examples of such ischemic, hypoxic, or hypoglycemic conditions include strokes or cerebrovascular accidents, carbon monoxide poisoning, hyperinsulinemia, cardiac arrest, drownings, suffocation, and neonatal anoxic trauma. The compounds should be administered to the patient within 24 hours of the onset of the hypoxic, ischemic, or hypoglycemic condition in order for the compounds to effectively minimize the CNS damage which the patient will experience.
The compounds are also useful in the treatment of neurodegenerative diseases such as Huntington's disease, Alzheimer's disease, senile dementia, glutaric acidaemia type I, multi-infarct dementia, and neuronal damage associated with uncontrolled seizures. The administration of these compounds to a patient experiencing such a condition will serve to either prevent the patient from experiencing further neurodegeneration or it will decrease the rate at which the neurodegeneration occurs.
As is apparent to those skilled in the art, the compounds the result of either disease or a lack of oxygen or sugar. As used in this application, the term "treat" refers to the ability of the compounds to prevent further damage or delay the rate at which any further damage occurs.
The compounds exhibit an anxiolytic effect and are thus useful in the treatment of anxiety. These anxiolytic properties can be demonstrated by their ability to block distress vocalizations in rat pups. This test is based upon the phenomenon that when a rat pup is removed from its litter, it will emit an ultrasonic vocalization. It was discovered that anxiolytic agents block these vocalizations. The testing methods have been described by Gardner, C. R., Distress vocalization in rat pups: a simple screening method for anxiolytic drugs. J. Pharmacol. Methods, 14: 181-187 (1985) and Insel et al., Rat pup ultrasonic isolation calls: Possible mediation by the benzodiapine receptor complex, Pharmacol. Biochem. Behav., 24: 1263-1267 (1986). The compounds also exhibit an analgesic effect and are useful in controlling pain.
The compounds of Formula I and Ia are muscle relaxants and are therefore useful for relieving muscle spasms. One method of demonstrating their utility as muscle relaxants is via the Straub Tail test. This screening procedure is based upon the observation that the administration of morphine to mice produces a sustained contraction of their sacrococcygeus muscle which causes their tail to be elevated at an angle of approximately 90.degree.. A muscle relaxant prevents contraction of this muscle and inhibits tail elevation. These tests have been described by K. O. Ellis, et al., Neurocharmacology, Vol. 13, pp. 211-214 (1974).
In order to exhibit any of these therapeutic properties, the compounds need to be administered in a quantity sufficient to inhibit the effect which the excitatory amino acids have upon the NMDA receptor complex. The dosage range at which these compounds exhibit this antagonistic effect can vary widely depending upon the particular disease being treated, the severity of the patient's disease, the patient, the particular compound being administered, the route of administration, and the presence of other underlying disease states within the patient, etc. Typically the compounds exhibit their therapeutic effect at a dosage range of from about 1 mg/kg/day to about 500 mg/kg/day for any of the diseases or conditions listed above. Repetitive daily administration may be desirable and will vary according to the conditions outlined above.
The compounds of the present invention may be administered by a variety of routes. They are effective if administered orally. The compounds may also be administered parenterally (i.e. subcutaneously, intravenously, intramuscularly, intraperitoneally, or intrathecally).
Pharmaceutical compositions can be manufactured utilizing techniques known in the art. Typically an antagonistic amount of the compound will be admixed with a pharmaceutically acceptable carrier.
For oral administration, the compounds can be formulated into solid or liquid preparations such as capsules, pills, tablets, lozenges, melts, powders, suspensions, or emulsions. Solid unit dosage forms can be capsules of the ordinary gelatin type containing, for example, surfactants, lubricants and inert fillers such as lactose, sucrose, and cornstarch or they can be sustained release preparations. In another embodiment, the compounds of Formulae I and Ia can be tableted with conventional tablet bases such as lactose, sucrose, and cornstarch, or gelatin, disintegrating agents such as potato starch or alginic acid, and a lubricant such as stearic acid or magnesium stearate. Liquid preparations are prepared by dissolving the active ingredient in an aqueous or non-aqueous pharmaceutically acceptable solvent which may also contain suspending agents, sweetening agents, flavoring agents, and preservative agents as are known in the art.
For parenteral administration the compounds may be dissolved in a physiologically acceptable pharmaceutical carrier and administered as either a solution or a suspension. Illustrative of suitable pharmaceutical carriers are water, saline, dextrose solutions, fructose solutions, ethanol, or oils of animal, vegetative, or synthetic origin. The pharmaceutical carrier may also contain preservatives, buffers, etc., as are known in the art. When the compounds are being administered intrathecally, they may also be dissolved in cerebrospinal fluid as is known in the art.
As used in this application:
The compounds may also be admixed with any inert carrier and utilized in laboratory assays in order to determine the concentration of the compounds within the serum, urine, etc., of the patient as is known in the art.
Neurodegenerative diseases are typically associated with a loss of NMDA receptors. Thus, the compounds of Formulae I and Ia may be utilized in diagnostic procedures to aid physicians with the diagnosis of neurodegenerative diseases. The compounds may be labeled with isotopic agents by techniques known in the art and utilized as imaging agents. They may then be administered to a patient in order to determine whether the patient is exhibiting a decreased number of NMDA receptors and the rate at which that loss is occurring.
The following examples are presented in order to further illustrate the invention. They should not be construed as limiting the invention in any manner.
US Referenced Citations (1)
| Number |
Name |
Date |
Kind |
|
4705781 |
Boast |
Nov 1987 |
|
Foreign Referenced Citations (1)
| Number |
Date |
Country |
| 0159889 |
Apr 1985 |
EPX |
Non-Patent Literature Citations (3)
| Entry |
| Derwent Abstract 88-251354/36 (Abstract of DE 3804-936-A). |
| Bennett et al., Life Sciences, vol. 39, pp. 2455-2461. |
| Pike et al., Biochimica et Biophysica Acta. 708 (1982) 203-209. |
Continuation in Parts (2)
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Number |
Date |
Country |
| Parent |
508333 |
Apr 1990 |
|
| Parent |
409478 |
Sep 1989 |
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Patent Grant
5095009
