Patent Grant
7378437
The present invention relates to specific classes of compounds and their use for the diabetes treatment.
More specifically it relates to the treatment of type 2 diabetes.
As it is well known, conventionally diabetes is usually divided in two types: diabetes of type 1, which mainly appears in young people, and diabetes of type 2, which affects elderly people.
Diabetes of type 1 is successfully treated with insulin; while diabetes of type 2 is only partially effective towards the insulin therapy. The type 2 diabetes is the most frequent one, particularly in elderly people. About 18-20% of the population over 65 years suffers from it (National Diabetes. Data Group “Diabetes in America” 2nd ed. Harris M. Ed. Bethesda, National Institutes of Health, 1995). By taking into account of the progressive ageing of the population (people over sixty-five now represent over 15% of the population) it is evident that the treatment of this disease represents a priority medical and social requirement.
Forms of diabetes also exist wherein the type 1 and 2 are contemporaneously present.
The insulin resistance has a significant clinical importance (Trends in Pharm. Sci. 21, 259-265, 2000) both in connection with the primary disease and its complications (vascular diseases, retinopathy, polyneuropathy, gastroenteropathy, nephropathy, etc.) (Martindale, The Extra Pharmacopoeia p. 342, 1996).
As it is specified also in a late publication (Trends in Pharm. Sci. 21, 259-265, 2000) the above requirement results still unsatisfied since no drug is able to effectively face the disease and its complications.
The drugs used in the diabetes therapy belong to the following therapeutic classes, defined on the basis of the pathogenetic role of the insulin resistance (Trends in Pharm. Sci. 21, 259-265 2000): insulin, sulphanylureas, metformin, inhibitors of alpha-glycosidase (acarbose) and thiazolidine diones (troglitazone).
Insulin is the most known drug and it is the reference one. The insulin therapy shows the following drawbacks:
Also the other therapeutical approaches are not without drawbacks, sometimes even remarkable. For example sulphanylureas, which are administered alone or in combination with insulin or with other oral hypoglycemizing drugs, can cause hypoglycemia. The metformin which is used alone or in combination with sulphanylurea, is contraindicated in the presence of renal and hepatic diseases, and can induce a state of lactic acidosis. Acarbose is used alone or in combination with sulphanylurea for reducing the postprandial glycemic levels, but it often induces side effects at the gastrointestinal system level. Troglitazone, which is only used in combination with insulin, can induce hepatotoxic effects.
The need was felt to have available drugs which could be administered to diabetic patients, also under treatment with hypoglycemizing drugs, preferably insulin, and able to increase the direct antidiabetic effect thereof, i.e. at pancreatic level, and to reduce the diabetes complications, in particular vascular diseases, retino-pathies, neuropathies, gastroenteropathies, nephropathies, etc.
It has now surprisingly and unexpectedly found that this technical problem can be solved with the class of drugs described hereunder.
An object of the present invention is the use in the diabetes treatment, preferably of type 2, of compounds or salts thereof, having the following general formula:
A-(B)b0—(C)c0—NO2 (I)
wherein:
R is the radical of a precursor drug having the following formula:
the acceptance criterion of the compounds according to this test is the following: test 4 is satisfied by the precursor compounds of B when the inhibition percentage as above defined is higher than or equal to 50%.
The preferred compounds to be used as precursors of R are as herein below defined:
other compounds that can be used in the treatment of diabetes, preferably of type 2 diabetes, are the nitrate salts of the compounds of formula (AC):
wherein Q is one of the two following substituents:
in (AC-1) the bond in position 2 of the pyridine ring indicates the site of attachement of Q to the aliphatic chain of formula (AC); the same for the bond on the tertiary aliphatic nitrogen atoms in (AC-2);
The precursor compound of B (precursor of the radical X2 in formula (I)) which meets test 4 is preferably selected from the following classes of compounds:
Preferably the precursor compound of B which meets test 5, is selected from the following compounds:
In formula (I) the precursor compound of B which meet test 4A and do not meet test 5 are for example the following: 1,4-butandiol, 6-hydroxyhexanoic acid, 4-hydroxybutyric acid, N-methyldiethanolamine, diethylenglycol, thiodiethylenglicol, 1,4-dioxan-2,6-dimethanol, tetrahydropyran-2,6-dimethanol, 4H pyran-1,4-2,6-dimethanol, tetrahydrothiopyran-2,6-dimethanol, 1,4-dithiane-2,6-dimethanol, cyclohexene-1,5-dimethanol, thiazol-2,5-dimethanol, thiophene-2,5-dimethanol, oxa-zol-2,5-dimethanol, preferably N-methyldiethanolamine, dietilenglycol, thiodiethylenglycol.
The precursor compounds of B of the above mentioned groups are prepared according to the methods known in the prior art and described, for example in “The Merck Index, 12th Ed. (1996), herein incorporated by reference. When available, the corresponding isomers and optical isomers can be used. 24,28-methylene-1α-hydroxyvitamin D2 is prepared according to EP 578,494.
More specifically, the above reported tests are the following:
Test 4 is a calorimetric test which allows to establish whether the precursors of B are able to inhibit the production of radicals from DPPS (2,2-diphenyl-1-picryl-hydrazyl) (M. S. Nenseter et Al., Atheroscler. Thromb. 15, 1338-1344, 1995). 100 μM solutions in methanol of the tested substances are prepared and an aliquot of each of said solutions is added to a 0.1 M DPPH solution in methanol After having stored the solutions at room temperature and sheltered from light for 30 minutes the absorbance is read at the wave length of 517 nm. The absorbance decrease with respect to that of the solution containing the same DPPH concentration is determined. The effectiveness of the tested compound in inhibiting the production of radicals is expressed by the following formula:
(1−As/Ac)×100
wherein As and Ac are respectively the absorbance values of the solution containing the tested compound together with DPPH and of the solution containing only DPPH.
The precursor of B satisfies test 4 if its effectiveness in inhibiting the radical production, as above defined, is equal to or higher than 50% at the indicated concentration (10−4 M).
Test 5 is a calorimetric test wherein 0.1 ml aliquots of solutions in methanol of the precursors of B at a concentration 10−4 M are added to a solution formed by 0.2 ml of 2 mM desoxyribose, 0.4 ml of phosphate buffer pH 7.4 100 mM and 0.1 ml of 1 mM FeII(NH4)2 (SO4)2 in 2 mM HCl. The test tubes containing the reaction mixtures are then maintained at 37° C. for one hour. Then 0.5 ml of a 2.8% solution in water of trichloroacetic acid and 0.5 ml of an aqueous 0.1 M solution of thiobarbituric acid are added in the order in each test tube. A reference blank is formed by adding the same 0.1 ml aliquot of methanol without the tested compounds. The test tubes are closed and heated in an oil bath at 100° C. for 15 minutes. A pink coloration-develops the intensity of which is proportional to the oxidative degradation of the desoxyribose. The solutions are cooled at room temperature and their absorbance is determined at 532 nm. The inhibition percentage of the precursor of B towards the radical production is calculated by means of the formula:
(1−As/Ac)×100
wherein As and Ac are respectively the absorbance values of the solution containing the tested compound and the iron salt and that of the solution containing only the iron salt, the compound meets test 5 when the percentage of inhibition of radical production as above defined from the precursor of B is higher than or equal to 50%.
Test 4A is carried out according to the method described by R. Maffei Facino, M. Carini G. Aldini, M. T. Calloni, Drugs Exptl. Clin. Res. XXIII (5/8) 157-165 1997. Test 4A is a test in vitro wherein erythrocytes isolated by standard techniques from Wister male rats (Charles River), are suspended for 4 days at 4° C. in a phisiological solution buffered at pH 7.4 with phosphate buffer. After this period of time an aliquot of suspension is taken and centrifuged at 1,000 rpm for 5 minutes and 0.1 ml of the centrifuged erythrocytes are diluted to 50 ml with sodium phosphate buffer obtaining a suspension of erythrocytes 0.2% by volume. No. 5 aliquots of 3.5 ml each of the diluted suspension are incubated at 37° C. in the presence of cumene hydroperoxide (270 μM in ethanol). This compound causes cell lysis, which causes an increase of the suspension turbidity; cell lysis progress can be followed by turbidimetry at 710 nm, by performing the readings at intervals of 30 minutes so as to determine the time (Tmax) at which there is the maximum emolysis or maximum turbidity. The so determined Tmax is assumed to be the time corresponding to 100% of erythrocyte lysis. To determine the inhibition of the hemolysis induced by cumene hydroperoxide, 2 mM ethanol solutions of precursors of B are preincubated for 30 minutes with 3.5 ml aliquots of the erythrocyte suspension as above prepared (No. 5 samples for each compound precursor of B), cumene hydroperoxide is added in the same above mentioned amounts and the hemolysis percentage is determined in the sample at the Tmax as the ratio between the absorbance of the suspension of the tested sample and that of the suspension containing only cumene hydoperoxide; the precursors of B meet the test if they inhibit the haemolysis induced by cumene hydroperoxide by a percentage >15%.
Preferably Y3 is selected from the following:
Preferably Y3 is an aroamtic ring having 6 atoms, containing one nitrogen atom, said aromatic ring having the two free valences respectively in positions 2 and 6, or 2 and 3 or 2 and 5 with respect to the heteroatom.
The preferred of Y3 is Y12 (pyridyl) substituted as above indicated. The bonds can also be in asymmetric position, for example Y12 (pyridyl) can be substituted also in position 2 and 3; Y1 (pyrazol) can be 3,5-disubstituted.
In general the precursor compounds of formula R=(AII) are well known in the art. The precursor compound of formula (AII) wherein RXII=(AV) and R2=(AV−1) can be prepared according to WO 97/25042. The compound of formula (AII) wherein RXII=(AVI) and R2=(AVI−1) can be prepared according to WO 97/31907. The precursor compound known as farglitizar can be prepared according to “Drugs of the future” 2001, 26(4) 354-363. The precursor compound of formula (AII) wherein RXII=(AXL) with s=0 and R2=(AVIII−1) can be prepared according to Proc. Natl. Acad. Sci 1999, 96(11) 6102. The precursor compound known as repaglinide is synthetized according to “Drugs of the future” 1996, 21, 694. The compounds known as mitiglinide, nateglinide, JTT-608 are synthetized according to “Drugs of the future” 2000, 25(10) 1034-1042, 694. The compounds pioglitazione and rosiglitazione can be synthetized according to “Drugs of the future” 1998 23(9) 977; the corresponding nitrate salts of these compounds can be prepared by obtaining said compounds in the free base form, then salified with nitric acid as described in WO 99/45004.
The compounds of formula (I) can be transformed into the corresponding salts. For example one route to prepare the salts is the following: when a nitrogen atom sufficiently basic to be salified is present in the molecule, the compound of formula (I) is reacted in organic solvent, such as for example acetonitrile, tetrahydrofuran, with an equimolecular amount of the corresponding organic or inorganic acid.
Examples of organic acids are: oxalic, tartaric, maleic, succinic, citric acid.
Examples of inorganic acids are: nitric, hydrochloric, sulphuric, phosphoric acid. Hydrochlorides and nitrates are preferred.
When in formula (I) c0=0 and b0=1 the preferred compounds are those wherein in radical R of formula (AII) with RXII=(AXL), M=CH, s=0, R1=H and R2 is in position 2 of the aromatic ring and is OH, or R1 is acetyloxy in position 2 of the ring and R2=H, B is a residue of an aromatic polyalcohol, preferably of a hydroxymethylphenol;
when in formula (I) c0=1 and b0=0 the preferred compounds are those wherein in the radical R of formula (AII) with RXII=(AXL), M=CH, s=0, R1=H and R2 is in position 2 of the aromatic ring and is OH, or R1 is acetyloxy in position 2 of the ring and R2=H, C is Yp where Yp is preferably the residue of bis(hydroxymethyl)pyridine;
when in formula (I) c0=1 and b0=1 the preferred compounds are those wherein in radical R of formula (AII) with RXII=(AXL), M=CH, and when:
The preferred compounds according to the present invention are those wherein the drug has formula (AII) and the compounds of formula (I) are the following: 2-acetyloxybenzoic acid 6-(nitrooxymethyl)-2-methylpyridinyl ester hydrochloride or nitrate, 2-acetyloxybenzoic acid 3-nitroxy methylphenyl ester, 2-acetyloxybenzoic acid 4-(nitrooxymethyl) phenyl ester, 2-acetyloxybenzoic acid 5-(nitrooxymethyl)-2-methylpyridinyl ester hydrochloride or nitrate, 2-(acetyloxy)benzoic acid 3-(nitrooxymethyl)-2-methyl pyridinyl ester hydrochloride or nitrate.
As said, the nitroderivatives of the invention are administered to patients suffering from diabetes both of type 1 and type 2, or in the cases wherein both are present (the so called intermediate diabetes forms). The compounds of the invention can also be administered to patients already under treatment with hypoglycemizing drugs, preferably insulin. The compounds of the invention are able to strengthen the direct antidiabetic effect, i.e. at a pancreatic level, and to reduce one or more diabete complications, in particular vascular and also retinopathies, neuropathies, gastroenteropathies, nephropathies complications, etc.
The compounds of the invention are particularly effective in the treatment of the type 2 diabetes, for which no commercial product has been found completely satisfactory.
The compounds of the invention are synthesized by the synthesis methods mentioned hereunder.
The choice of the reactions for each method depends on the reactive group present in the drug molecule, in the precursor compound of B, and in the precursor compound of C.
The reactions are carried out by methods well known in the prior art, which allow to obtain bonds among the drug, the precursor compound of B and the precursor compound of C as above defined.
When the reactive function of the drug (for example —CO—OH, —OH) is involved in a bond of covalent type, for example of ester, amide, ether type, said function can be restored by the well known methods in the prior art.
Some synthesis schemes for obtaining the compounds of the invention are reported hereinafter:
A) Synthesis of the compound of formula (I).
Alternatively, the halide Hal-X1—COCl can be used wherein Hal is preferably bromine, which is reacted with the compound of formula (IA.2)
In the previous scheme the nit ration can alternatively be carried out on the acid compound of formula (2B.3).
The compounds object of the present invention are formulated in the corresponding pharmaceutical compositions for parenteral, oral and topical use according to the techniques well known in the field, together with the usual excipients; see for example the volume “Remington's Pharmaceutical Sciences 15th Ed.”.
The amount on a molar basis of the active principle in these formulations is the same, or lower, with respect to that used as antiinflammatory and/or analgesic drug of the corresponding precursor drug.
The daily administrable doses are those of the antiinflammatory and/or analagesic precursor drugs, or optionally lower. The daily doses can be found in the publications of the field, such as for example in “Physician's Desk reference”.
The following Examples have the purpose to illustrate the invention and they are not to be considered as limitative of the same.
To thionyl chloride (11.6 ml, 158 mmoles), cooled at 0° C., 2,6-bis-(hydroxymethyl)pyridine (4 g, 28 mmoles) is very slowly added. The obtained solution is left under stirring for 2 hours at room temperature, then the thionyl chloride in excess is evaporated at reduced pressure. The obtained residue is treated with chloroform and it is evaporated again at reduced pressure to eliminate the thionyl chloride residues. The crude product is treated with chloroform and washed with water. The organic phase is anhydrified with sodium sulphate and dried obtaining 4.81 g of the product as a white solid having m.p. 76-78° C.
To a solution of acetylsalicylic acid (1.6 g, 8.88 mmoles) in N,N′-dimethylformamide (20 ml) and under stirring, sodium ethylate (0.64 g, 8.88 mmoles) is added. After 30 minutes the obtained solution is added to a solution of 2,6-bis-(chloromethyl)pyridine (4.72 g, 26.81 mmoles) in N,N′-dimethylformamide (20 ml). The solution is left at room temperature for 7 days, under stirring, then it is diluted with ethyl ether and washed with water. The separated organic phases are anhydrified with sodium sulphate and the solvent is evaporated at reduced pressure. The reaction crude product is purified by chromatography on silica gel eluting with n-hexane/ethyl acetate 7/3. 1.7 g of the product are obtained as a yellow oil.
1H-NMR (200 MHz)(CDCl3): 8.10 (1H,d); 7.74 (1H,t); 7.57 (1H,t); 7.42 (1H,d); 7.33 (2H,m); 7.11 (1H,d); 5.42 (2H,s); 4.67 (2H,s); 2.41 (3H, s).
To a solution of 2-acetyloxybenzoic acid 6-(chloro methyl)-2- methylpyridinyl ester (1.5 g, 4.7 mmoles) in acetonitrile (20 ml) maintained under stirring, silver nitrate (1.3 g, 7.65 mmoles) is added. The solution is heated at 80° C., maintaining it sheltered from light, under stirring for 30 hours. The formed silver chloride is filtered, the solvent is evaporated. The reaction crude product is purified by chromatography on silica gel eluting with n-hexane/ethyl acetate 7/3. 1.2 g of product are obtained as a yellow oil.
1H-NMR (200 MHz) (CDCl3): 8.10 (1H,d); 7.74 (1H,t); 7.57 (1H,t); 7.42 (1H,d); 7.33 (2H,m); 7.11(1H, d); 5.60(2H, s); 5.42 (2H, s); 2.41 (3H, s).
To a solution of 2-acetyloxybenzoic acid 6-(nitrooxymethyl)-2-methylpyridinyl ester (1 g, 2.88 mmoles) in ethyl acetate (20 ml) cooled at 0° C., a solution of ethyl acetate/HCl 5M is added by dropping under stirring. It is left for 1 hour at 0° C., then the temperature is let reach the room values. The formed precipitate is filtered and washed with ethyl ether. 900 mg of a solid product are obtained.
Elementary Analysis
1H-NMR (200 MHz) (CDCl3): 8.10 (2H,m); 7.7 (1H,t); 7.56 (2H,d); 7.48(1H,t); 7.30 (1H,d); 5.74 (2H,s); 5.43 (2H,s); 2.20 (3H, s)
3-hydroxymethylphenol (10 g, 0.08 moles) is dissolved in toluene (50 ml) containing triethylamine (9.8 g, 0.1 moles). To the so obtained solution, a solution of the acetylsalicylic acid chloride (16 g, 0.08 moles) in toluene (50 ml) is added at the temperature of 5-10° C. under stirring. The mixture is maintained at a temperature within the above mentioned range, under stirring for 2 hours, then poured in water and then extracted with dichloromethane (2×100 ml) The organic phase is separated, washed in sequence with a solution of potassium carbonate at 25% w/v, with water, with a 3% hydrochloric acid solution, and lastly again with water, then anhydrified with sodium sulphate and the solvent evaporated under vacuum. The residue is crystallized from isopropanol. 3-hydroxymethylphenyl ester of the 2-acetoxybenzoic acid (45.8 g, 0.16 moles, yield 80%) is obtained.
M.p. 79-81° C. 1H NMR(CDCl3) δ (ppm): 2.29 (s,3H); 4.71 (s,2H); 7.07-8.2 (m, aromatic compounds, 8H).
A solution of fuming nitric acid (3.92 g, 62.2 mmoles, 3 moles with respect to the moles of the hydroxyester under reaction) and sulphuric acid 96% (6.10 g, 62.2 mmoles, 3 moles with respect to the moles of the hydroxyester under reaction) in dichloromethane (25 ml) is cooled at 0° C. and added in 1 hour time, under stirring and under nitrogen atmosphere, with a solution of 3-hydroxymethylphenyl ester of the 2-acetoxybenzoic acid (6 g, 20.7 mmoles) in 25 ml of dichloromethane. The mixture is then diluted with dichloromethane (50 ml) and poured in water and ice (100 g) The organic phase is separated, washed with water, anhydrified with sodium sulphate and the solvent evaporated under vacuum. The residue is crystallized from isopropanol obtaining the 3-nitrooxymethylphenyl ester of the 2-acetoxybenzoic acid (5.6 g, 17 mmoles, yield 82%).
M.p. 61-62° C. 1H NMR(CDCl3) δ (ppm): 2.31 (s,3H); 5.44 (s,2H); 7.16-8.22 (m, aromatic compounds, 8H).
To a solution of 1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolacetic acid (20.08 g, 56.12 mmoles) in chloroform (200 ml) and dimethylformamide (20 ml), 3-hydroxybenzaldehyde (6.82 g, 55.85 mmoles), N,N′-dicyclohexyl carbodiimide (11.6 g, 56.22 mmoles) and N,N-dimethylamino pyridine (0.306 g, 2.5 mmoles) are in the order added. The mixture is maintained under stirring at room temperature for 6 hours. The precipitate is filtered and the organic phases are washed with water (100 ml×2), anhydrified with sodium sulphate and the solvent is evaporated at reduced pressure. The crude product is purified by chromatography on silica gel eluting with methylene chloride. 20.99 g of 1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolacetic acid 3′-formylphenyl estere are obtained. Yield 81%.
A solution of 1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolacetic acid 3′-formylphenyl ester (20 g, 4.33 mmoles) in ethyl acetate (200 ml) is hydrogenated in the presence of palladium 5% on carbon (2 g) at room temperature under stirring, using an hydrogen pressure of about 2.5 atm. After 30 minutes the reactor is discharged removing the catalyst by filtration under nitrogen atmosphere. The solvent is evaporated at reduced pressure and the residue is purified by chromatography on silica gel eluting with methylene chloride/acetic acid (95:5 v/v). 14 g of 1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolacetic acid 3′-(hydroxymethyl)phenyl ester are obtained as a yellow solid. Yield 73%.
To a solution of 1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolacetic acid 3′-(hydroxymethyl)phenyl ester (13 g, 2.81 mmoles) in chloroform (200 ml) and cooled by an ice bath, a solution of SOCl2 (2.06 ml, 2.81 mmoles) in chloroform (50 ml) is added. The mixture is maintained under stirring for 30 minutes in ice bath and for 20 hours at room temperature. The solution is washed first with a bicarbonate solution and then with water. The organic phase is anhydrified with sodium sulphate and the solvent is evaporated at reduced pressure. The residue is purified by chromatography on silica gel eluting with methylene chloride/hexane (1:1 v/v). 9.86 g of 1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolacetic acid 3′-(chloromethyl)phenyl ester are obtained as a yellow solid.
M.p. 147-150° C. Yield 73%.
To a solution of 1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolacetic acid 3′-(chloromethyl)phenyl ester (9.86 g, 2.04 mmoles) in acetonitrile (100 ml) silver nitrate (4.87 g, 2.87 mmoles) is added and the mixture is heated at 80° C. under stirring for 15 hours. It is cooled, the precipitate is filtered and the solvent is evaporated at reduced pressure. The residue is purified by chromatography on silica gel eluting with methylene chloride/hexane (1:1 v/v). 9.83 g of 1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolacetic acid 3′-(nitrooxymethyl)phenyl ester are obtained. M.p. 115-119° C.
Yield 94.5%. 1H NMR (CDCl3) 7.70 (2H,d); 7.49 (2H,d); 7.42 (1H,t); 7.14-7.06 (4H,m); 6.90 (1H,d); 6.70 (1H,dd); 5.42 (2H,s); 3.93 (2H,s); 3.86 (3H,s); 2.48 (3H,s).
To a solution of α-methyl[4-(2-methylpropyl)benzene] acetic acid (10 g, 48.48 mmoles) in chloroform (100 ml) and N,N-dimethylformamide (6 ml) 1,1′-carbonyldiimidazol (7.86 g, 48.48 mmoles) is added. After 1 hour the obtained solution is treated with (S)-N-acetylcysteine (7.91 g, 48.47 mmoles) and it is left at room temperature for 24 hours. The reaction mixture is washed with HCl 5%, then with water and lastly with brine. The organic phase is anhydrified with sodium sulphate and then evaporated at reduced pressure. The obtained residue is purified by chromatography on silica gel eluting with ethyl acetate. 13.3 g of the expected product are obtained under the form of an oil.
1H-NMR (CDCl3) : 10.17 (1H,s) 7.13 (2H,d) 6.54 (1H,d), 4.76 (1H,m), 3.93 (1H,q), 3.42-3.30 (2H,m), 2.49 (2H,d), 1.85-1.83 (4H,m), 1.55 (3H,d), 0.93 (6H, d)
To a solution of (S)-N-acetyl-S-{α-methyl[4-(2-methylpropyl)benzene]acetyl}cysteine (12.8 g, 36.4 mmoles) in tetrahydrofuran (100 ml), triphenylphosphine (28.65 g, 109.23 mmoles) and carbon tetrabromide (36.23 g, 109.23 mmoles) are added. The reaction mixture is left under stirring for 48 hours at room temperature. The solvent is removed by evaporation at reduced pressure. The obtained crude product is purified by chromatography on silica gel eluting with cyclohexane/ethyl acetate 1/1. 5.79 g of the ester are obtained in the form of an oil.
To a solution of the ester obtained at the end of the previous step (5.5 g, 11.3 mmoles) in acetonitrile (100 ml), silver nitrate (2.69 g, 15.8 mmoles) is added. The reaction mixture is heated for 24 hours under reflux sheltered from light. The formed salt is removed by filtration and the solution is evaporated at reduced pressure. The obtained residue is purified by chromatography on silica gel eluting with cyclohexane/ethyl acetate 7/3. 1.18 g of (S)-N-acetyl-{α-methyl[4-(2-methylpropyl)benzene]acetyl}cysteine 4-(nitroxy)butyl ester are obtained under the form of an oil.
1H-NMR (CDCl3) : 7.27-7.09 (4H,m), 6.19 (1H,d), 4.75 (1H,m), 4.47 (2H,t), 4.15-4.02 (2H,m), 3.86 (1H,q), 3.31 (2H,d), 2.44 (2H,d), 1.89 (3H,d), 1.86-1.76 (SH, m), 1.51 (3H,d), 0.89 (6H,d).
Elementary Analysis:
CalculatedC: 56.39% H: 6.88% N: 6.00% S: 6.84%
Found C: 56.22% H: 6.79% N: 5.88% S: 6.92%
To a solution of ferulic acid (10 g, 51.5 mmoles) in THF (400 ml), cooled in a water bath, triphenylphosphine (27.01 g, 103 mmoles) and carbon tetrabromide (34.1 g, 103 mmoles) are in the order added. The mixture is maintained under stirring for 5 hours at room temperature. When the reaction is over, the formed triphenylphosphinoxide is filtered and the solvent is evaporated at reduced pressure. The residue is purified by chromatography on silica gel eluting with hexane/ethyl acetate (7:3 v/v). 7.75 g of trans-3-[4-hydroxy-3-methoxyphenyl]-2-propenoic acid 4-bromobutyl ester are obtained as a white solid. M.p. 86-89° C. Yield 46%.
To a solution of trans 3-[4-hydroxy-3-methoxyphenyl]-2-propenoic acid 4-bromo butyl ester (2 g, 6.1 mmoles) in CHCl3 (20 ml), a mixture of acetyl salicylic acid (1.1 g, 6.1 mmoles) in DMF (2 ml) is added and cooled at 0° C. Then DCC (1.50 g, 7.2 mmol) and DMAP (74 mg, 6×10−3 mmoles) are added. The solution is left at the same temperature for 30 minutes and then it is let reach the room temperature, maintaining this last temperature for 16 hours. The precipitate is filtered and the solvent is evaporated at reduced pressure. The residue is dissolved in ethyl acetate (100 ml×2 times) and washed with water and NaCl. The organic phase is anhydrified and the solvent is evaporated at reduced pressure.
The residue is purified by chromatography on silica gel eluting with hexane/ethyl acetate (8:2 v/v), obtaining the trans-3-[4-[2-(acetyloxy)benzoyloxy]-3-methoxyphenyl]-2-propenoic acid 4-bromobutyl ester (1.1 g, Yield 37%).
1H NMR: 8.25 (1H,d); 7.65 (2H,m); 7.40 (1H,t); 7.20 (4H,m); 6.39 (1H,d); 4.25 (2H,t); 3.85 (3H,s); 3.47 (2H,t); 2.29 (3H, s); 2.01 (2H,m); 1.89 (2H,m):
To a solution of 3-[4-[2-(acetyloxy) benzoyloxy]-3-methoxyphenyl]-2-propenoic acid 4-bromobutyl ester-(1 g, 2.03 mmoles) in acetonitrile (10 ml), silver nitrate (0.530 g, 3.11 moles) is added, under stirring, sheltered from light. It is heated at 80° C. for 8 hours and at the end it is cooled at room temperature. The precipitate is filtered and the solvent is evaporated at reduced pressure.
The residue is purified by chromatography on silica gel eluting with hexane/ethyl acetate (7:3 v/v) obtaining 3-[4-[2-(acetyloxy)benzoyloxy]-3-methoxyphenyl]-2-acid 4-nitroxybutyl ester (506 mg) as a white solid. Yield 52.6%.
1H NMR: 8.24 (1H, d); 7.65 (2H, m); 7.39 (1H, t); 7.18-7.14 (4H, m); 6.39 (1H, d); 4.51 (2H, t); 4.25 (2H, t); 3.85 (3H, s); 2.95 (3H, s); 1.89-1.82 (4H, m).
To a mixture of 4-hydroxybenzaldehyde (20.75 g, 0.17 moles) and triethylamine (0.205 g, 2.4 mmoles) in methylene chloride (300 ml) maintained under stirring under inert nitrogen atmosphere, cooled at a temperature between −5° C. and 0° C., acetylsalicyloil chloride (41.25 g, 0.21 moles) is added by small parts in one hour time. After 15 minutes from the addition completion, water (250 ml) is added and the phases are separated. The aqueous phase is recovered and extracted with methylene chloride. The organic phases are put together, washed with a carbonate solution at 5% (150 ml×2) and then with water (125 ml×2). The organic phase is anhydrified with sodium sulphate in the presence of decolorizing carbon. It is filtered under vacuum and the solvent is evaporated at reduced pressure with a bath temperature not higher than 40° C., obtaining 48.2 g of 2-(acetyloxy)benzoic acid 4-(formyl)phenyl ester. The reaction crude product is used without further purification.
A solution of 2-(acetyloxy)benzoic acid 4-(formyl)phenyl (48.2 g, 0.18 moles) ester in ethyl acetate (500 ml) is hydrogenated in the presence of 5% palladium on carbon (4 g) at room temperature under stirring, using an hydrogen pressure of about 2.5 atm. After 30 minutes the reactor is discharged and the catalyst is removed by filtration under nitrogen atmosphere.
The organic phase is washed with a 5% sodium, bicarbonate solution and with water. It is anhydrified with sodium sulphate and the solvent is evaporated at reduced pressure. The residue is used without further purification.
To a mixture of 2-(acetyloxy)benzoic acid 4-(hydroxy methyl)phenyl (51.5 g, 0.18 moles) and SOCl2 (153 ml) maintained under stirring, dimethyl formamide (140 ml) is added at room temperature and it is left under stirring for one hour. At the end the thionyl chloride is evaporated at reduced pressure at a bath temperature lower than 40° C. The thionyl chloride traces in the compound are removed by treating the solid residue with toluene (60 ml×2). The solvent is removed by evaporation at reduced pressure with a bath temperature lower than 40° C. The crude product is. purified by crystallization with isopropyl ether to give 2-(acetyloxy)benzoic acid 4-(chloromethyl)phenyl ester (32.9 g, 0.10 moles). Yield 60%.
1H NMR: 8.25 (1H,d); 7.68 (1H,t); 7.43 (3H,m); 7.20 (3H,m); 4.60 ( 2H,s); 2.34 (3H,s).
To a solution of 2-(acetyloxy)benzoic acid 4-(chloro methyl)phenyl, ester (32.9 g, 0.10 moles) in acetonitrile, silver nitrate (22.2 g, 0.12 moles) is added, under stirring, sheltered from light. It is heated at 70° C. for 4 hours and then cooled at room temperature. The precipitate is filtered and the solvent is evaporated at reduced pressure.
The residue is purified by chromatography on silica gel eluting with hexane/ethyl acetate (7:3 v/v) to give 2-(acetyloxy)benzoic acid 4-(nitroxymethyl)phenyl ester (16.6 g, 0.05 moles). M.p. 86-88° C. Yield 50%.
1H NMR (CDCl3): 8.21 (1H,dd); 7.66 (1H,dt); 7.42 (3H,m); 7.20 (3H,m); 5.40 (2H, s), 2.25 (3H,s)
To evaluate the strengthening effect of the drugs of the invention on the antidiabetic activity of insulin, animals (rats) are treated with a fructose rich diet (Am. J. Physiol. 275, R788-R792, 1998). In this way an insulinic resistance is induced in the animals. Under such conditions the animal does not respond any longer to the usual insulin doses.
The pharmacological test is a test in vitro and consists in determining the vasorelaxing activity induced by the products of the invention, measured on an isolated vessel (aorta) taken from animals treated as above mentioned. The test in vitro is carried out both in the presence and in absence of LNNA (N-nitro-L-Arginine), which is an irreversible inhibitor of the nitric oxide synthethases, to verify if the vasorelaxing effect depends on the protective endogenous substances (nitric oxide).
The capability of the compounds of the invention to exert a vasorelaxing effect both in the presence and in absence of vasoprotective substances in such conditions of experimental diabetes, (animals with a fructose rich diet, and treated with or without LNNA), is an index which allows to evaluate the antidiabetic action of the tested compound.
In the pharmacological experiment isolated vessels are used, taken from rats which have developed, as said, an insulinic resistance condition induced by administering for 4 weeks a fructose rich diet.
Preparation of Tissues
Male Sprague Dawley rats having an average weight equal to 150-200 g were sacrificed and bled. The abdomi-nal aorta was removed and suitably prepared for determining the myorelaxing activity in vitro according to the method described by Vogel G. H. et al., Drug Discovery Evaluation-Pharmacological Assays page 32, 1996.
A part of the specimen is treated with LNNA.
The tissues are precontracted with phenylephrine (10 μM) and the relaxation was determined in the presence or in absence of the compounds of the invention or of the reference standards. The compounds were dissolved in dimethylsulphoxide and tested at doses which do not meaningfully modify the vascular tone in the non insulin resistant animal (subjected to normal diet). The results are reported in Table 1 and are expressed as a percentage with respect to the vasorelaxing effect measured in the controls.
In Table 1 the compound of comparative Example 3 is the indomethacin ester with m-nitrooxymethylphenol, the compound of Example 6 is the acetylsalicylic acid ester with p-nitrooxymethylphenol, the compound of Example 2 is the acetylsalicylic acid ester with m-nitrooxymethylphenol, the compound of Example 1 is the acetylsalicylic acid ester with 6-(nitrooxymethyl)-2-hydroxymethyl pyridine.
The results of the pharmacological test contained in the Table show that the compounds of the invention are able to induce a vasorelaxing effect both in the presence and in absence of vasoprotective substances (nitric oxide) in conditions of experimental diabetes.
The indomethacin ester (Example 3 comp.) and the sodium nitroprussiate, both NO-donor compounds, on the contrary, did not result active.
The metformin, which is a drug used in the diabetes therapy, is active only in the absence of the inhibitor of the NO synthesis.
| Number | Date | Country | Kind |
|---|---|---|---|
| MI2000A2201 | Oct 2000 | IT | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP01/11665 | 10/9/2001 | WO | 00 | 4/11/2003 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO02/30867 | 4/18/2002 | WO | A |
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|---|---|---|---|
| 4452806 | Rizzi et al. | Jun 1984 | A |
| 5518998 | Backstrom et al. | May 1996 | A |
| 5597847 | Matji et al. | Jan 1997 | A |
| 5861426 | Del Soldato et al. | Jan 1999 | A |
| 6040341 | Del Soldato et al. | Mar 2000 | A |
| 6054587 | Reddy et al. | Apr 2000 | A |
| 6211233 | Del Soldato | Apr 2001 | B1 |
| 6613784 | Benedini et al. | Sep 2003 | B1 |
| Number | Date | Country |
|---|---|---|
| 0 578 494 | Jan 1994 | EP |
| 0061537 | Oct 2000 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20040023890 A1 | Feb 2004 | US |
