HK1004552B - Substituted pyridyl-dihydroxyheptenoic acid and its salts - Google Patents

Description

The invention relates to a substituted pyridyl dihydroxyheptanoic acid, its salts, manufacturing process and use in pharmaceuticals.

Lactone derivatives isolated from mushroom cultures are known to be inhibitors of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase (HMG-CoA reductase) [Mevinolin, EP 22 478; US-4 231 938].

Pyridine-substituted dihydroxyheptanoic acids are also known to be inhibitors of HMG-CoA reductase [EP 325 130; EP 356 788 EP 307 342; EP 306 929].

It was now found that the substituted pyridyl dihydroxyheptanoic acid of the formula and their salts, possibly in an isomeric form, have a superior inhibitory effect on HMG-CoA reductase and thus have a surprisingly good effect on lowering blood cholesterol.

The substituted pyridyl dihydroxyheptanoic acid according to the invention may be present as its salts, which are generally referred to as salts with organic or inorganic bases.

The present invention prefers salts which are physiologically harmless. Physiologically harmless salts of the pyridyl dihydroxyheptanoic acid substituted in accordance with the invention may be metal or ammonium salts. The preferred salts are sodium, potassium, magnesium or calcium salts and ammonium salts derived from ammonia or organic amines such as methyllamine, ethylamine, propylamine, isopropylamine, diethylamine, triethylamine, diisopropylamine, diethylamine, triethylamine, dicloxylamine, arginine, lylamine or ethylene. The substitutes are sodium and potassium.

The substituted pyridyl dihydroxyheptanoic acid and its salts have two asymmetric carbon atoms, namely the two carbon atoms to which the hydroxy groups are bound, and can therefore exist in various stereochemical forms. The invention concerns both the individual isomers and their mixtures. Thus, the substances of the invention may be present in the erythro-configuration or in the threo-configuration depending on the relative position of the hydroxy groups: Other

The erythro configuration is preferred.

In turn, there are two enantiomers of both threon and erythro-configurations, namely 3R,5S isomers and 3S,5R isomers (erythro-form) and 3R,5R isomers and 3S,5S isomers (threo-form), of which the 3R,5S/3S,5R racemates and the 3R,5S enantiomers are preferred.

In addition, due to the double bonding, the substances of the invention may be in E-configuration or Z-configuration, preference being given to those compounds which are E-configured.

The preferred enantiomers are the (+) enantiomers of the substituted pyridyl dihydroxyheptanoic acid in the erythro- ((E)) configuration and their salts.

The substituted pyridyl dihydroxyheptanoic acid of formula (I) and its salts, where appropriate in an isomeric form, are produced by the [A] in the case of racemic products the corresponding racemic ester of formula (II) in which R1 stands for C1-C4 alkyl or benzyl, hydrolysed, or[B] in the case of stereoisomeric uniform products first the racemic ester of formula (II) with the ((+) or (-) enantiomers of the amine of formula (III) in which: R2 means C1-C4 alkyl substituted with hydroxy, as applicable, and R3 stands for hydrogen, halogen, C1-C4-alkyl or C1-C4-alkoxy, in the corresponding diastereomers of the amide of formula (IV) is transferred, separating the mixture of diastereomeric amides into the individual diastereomers by chromatography or crystallization, and then hydrolyses the pure diastereomeric amides to the enantiomeric pure products.

The following diagram illustrates the procedure:

The hydrolysis of esters (II) is generally carried out by treating the esters in inert solvents with bases, generally first producing the salts, which are then transferred to the free acid (I) in a second step by treatment with acid.

The solvent used for the hydrolysis of esters is water or the organic solvent used for ester desiccation. These include alcohols such as methanol, ethanol, propanol, isopropanol or butanol, or ethers such as tetrahydrofuran or dioxan, or dimethylformamide or dimethyl sulfoxide.

The usual inorganic bases are suitable as bases for the ester hydrolysis, preferably alkaline hydroxides or alkaline hydroxides such as sodium hydroxide, potassium hydroxide or barium hydroxide, or alkaline carbonates such as sodium or potassium carbonate or sodium hydrocarbonate, or alkaline alcohols such as sodium ethanolate, sodium methanolate, potassium methanolate, potassium methanolate or potassium ter-butanolate.

The ester hydrolysis is generally carried out in a temperature range of -10°C to +100°C, preferably from +20°C to +80°C.

Generally, the ester hydrolysis is carried out at normal pressure, but it is also possible to work at low or high pressure (e.g. 0.5 to 5 bar).

In the hydrolysis process, the base is generally used in a quantity of 1 to 3 moles, preferably 1 to 5 moles, relative to 1 mole of the ester.

In the first step of hydrolysis, the salts of the acid according to the invention are produced, which can be isolated. The acid according to the invention is obtained by treating the salts with ordinary inorganic acids. These include preferably mineral acids such as hydrochloric acid, bromohydrochloric acid, sulfuric acid or phosphoric acid.

The conversion of esters (II) with enantiomeric pure amines (III) to diastereomeric amides (IV) is generally carried out in inert solvents.

The solvents used for this purpose are the organic solvents used for starch production, preferably ethers such as diethyl ether, dioxane or tetrahydrofuran, or chlorinated hydrocarbons such as methylene chloride or chloroform or dimethyl formamide.

The implementation is generally carried out in a temperature range of 0°C to 100°C, preferably from +20°C to +80°C.

The implementation is generally carried out at normal pressure, but it is also possible to work at low or overpressure.

It has been shown to be advantageous in practice to use either the amine directly as a very large surplus solvent or to use up to 10 times the surplus when using another solvent.

The diastereomers amide (IV) are hydrolysed by conventional methods, such as by treating the amide with bases or acids in inert solvents.

Inert solvents are water and/or organic solvents.Alcohols such as methanol, ethanol, propanol or isopropanol or ethers such as diethyl ether, dioxan or tetrahydrofuran are preferable as organic solvents.Water and water/alcohol mixtures are particularly preferable.

The most common inorganic or organic acids are suitable for the hydrolysis of amides, preferably hydrochloric acid, hydrobromic acid, sulphuric acid, methanesulfonic acid or toluene sulfonic acid.

The usual inorganic bases such as sodium or potassium hydroxide or sodium or potassium methanolate or ethanolate or sodium or potassium carbonate are suitable as bases for amide hydrolysis.

In the case of phenethylamide, hydrolysis of the amide in ethanolic hydrochloric acid and in the case of phenylglycinolamide with baking soda is preferable, if necessary in the presence of alcohol.

The hydrolysis of diastereomeric amides (IV) generally occurs in a temperature range of 0 to 150 °C, preferably between +20 and +100 °C.

Hydrolysis of the amide is generally carried out at normal pressure, but may also be carried out at over or under pressure.

In addition, it is also possible to produce the enantiomeric pure salts of formula (I) by separating the corresponding racemates using the usual methods of chromatography.

The amines (III) used as starting materials are known or can be produced by known methods.

The diastereomeric amines (IV) are new and are valuable intermediates for the production of enantiomeric pure substituted pyridyl dihydroxyheptanoic acid and its salts.

The substituted pyridyl dihydroxyheptanoic acid, its salts and isomeric forms, as described in the invention, have valuable pharmacological properties which are superior to those of the present invention, in particular they are highly effective inhibitors of 3-hydroxy-3-methyl-glutaryl coenzyme A (HGM-CoA) reductase and, as a consequence, inhibitors of cholesterol biosynthesis. They can therefore be used to treat hyperlipoproteinemia or arteriosclerosis. The active substances according to the invention also have a lowering effect on blood cholesterol levels.

The pharmacological effect of the substances of the invention was determined in the following tests: A) The enzyme activity was determined modified according to G.C. Ness et al., Archives of Biochemistry and Biophysics 197, 493-499 (1979). Male ricorates (body weight 300 to 400 g) were treated for 11 days with ultraminid powder feed with 40 g of cholestyramine/kg of feed added. After decapitation, the animals' livers were removed and given on ice. The livers were crushed and in the Potter Elvejem homogeniser 3 times in 3 volumes of 0,1 mcharose, 0.05 m KCl, 0.04 m KxHy Phosphates (mixture of K2HPO4 and KH2PO4 with pH 7.2), 0.03 m ethylene glycol tetraethylenediamine, 0.00 m DSP (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (E) (EThe pellet is incorporated into a 1/4 volume SPE buffer, re-homogenised and then centrifuged again for 60 minutes. The pellet is incorporated into a 5 times its volume SPE buffer, homogenised and frozen at -78°C and stored (desulphurisation). For the test, the test compounds (or mevinolin as reference) were dissolved in dimethylformamide with the addition of 5 vol. % 1 n NaOH and introduced into the enzyme test at 10 μl in various concentrations, starting after 20 minutes of pre-incubation of the enzyme compounds at 37°C.The test solution was 0.380 ml and contained 4 μMol of glucose-6 phosphate, 1.1 mg of bovine serum albumin, 2.1 μMol of diothyrite, 0.35 μMol of NADP (β-nicotinamide adenine dinucleotide phosphate), 1 unit of glucose-6 phosphate dehydrogenase, 35 μMol of KxHy phosphate pH 7.2, 20 μl of enzyme preparation and 56 nMol of 3-hydroxy-3-methylglutaryl coenzyme A (glutaryl-3-14C) at 100 000 dpm. Other The reaction was incubated for 60 minutes at 37°C and stopped by adding 300 μl of 0.25 m HCl. After a 60-minute incubation at 37°C, the solution was centrifuged and 600 μl of the residue was applied to a 0.7 x 4 cm column filled with a 5-chloride anion exchanger with a grain size of 100 to 200 meshes.IC50 values were determined by ordering the percentage inhibition against the concentration of the test compound by intrapolation. To determine the relative inhibitory potency, the IC50 of the reference substance mevinolin was set to 100 and compared with the simultaneously determined IC50 of the test compound. (b) The serum cholesterol lowering effect of the compounds of the invention on blood cholesterol levels in dogs was found in several weeks of feeding experiments, in which the substance to be studied was given once daily in a capsule to healthy beagle dogs for several weeks in combination with the feedingstuff.i.e. before, during and after the period of application of the test substance cholestyramine (4 g/100 g feed 9 as bile acid sequestrant). The dogs were given normal blood samples twice weekly and serum cholesterol was measured enzymatically using a commercial test kit, and serum cholesterol levels during the application period were compared with serum cholesterol levels before the application period (controls).

The present invention also covers pharmaceutical preparations containing one or more compounds of general formula (I) in addition to inert, non-toxic, pharmaceutically useful auxiliaries and carriers, or consisting of one or more active substances of formula (I), and methods for the manufacture of such preparations.

The active substances of formula (I) should be present in these preparations in a concentration of between 0.1 and 99.5% by weight, preferably between 0.5 and 95% by weight of the total mixture.

In addition to the active substances of formula (I), the pharmaceutical preparations may contain other active substances.

The above pharmaceutical preparations may be produced in the usual way by known methods, for example by the excipient or carrier.

In general, it has been shown to be beneficial to administer the active substance (s) of formula (I) in total amounts of approximately 0,1 μg/kg to approximately 100 μg/kg, preferably in total amounts of approximately 1 μg/kg to 50 μg/kg body weight every 24 hours, where appropriate in several single doses, to achieve the desired result.

However, it may be beneficial to deviate from the amounts mentioned, where appropriate, depending on the type and body weight of the subject treated, the individual's behaviour towards the medicinal product, the nature and severity of the disease, the method of preparation and application, and the time or interval at which the administration takes place.

Examples of implementation Example 1

The following substances are to be classified in the same category as the active substance: and

Example 2

The following substances are to be classified in the same heading as the active substance: Other

Method A - Racemat separation with R- ((+) -phenylethylamine

(a) Production and separation of the diastereomeric phenethylamides Other 4,7 g (10 mmol) methyl-erythro- ((E) -4- ((fluorphenyl) -2,6-diisopropyl-5-methoxymethylpyrid-3-yl) -3,5-dthydroxy-hept-6-enoate is dissolved in 20 ml of R- ((+) -phenethylamine and heated for 72 h at 40°C. The reaction solution is poured on 150 ml of water and the solution is set to pH 4 with 1 N hydrochloric acid. The combined organic extracts are then extracted several times with ether. The combined organic extracts are washed with saturated sodium chloride solution, dried with magnesium sulphate and pressed. After a pre-treatment with silica gel 63-200 μl (petroleum sulphate 4/6/F 6/L) a 1/15-silicate (petroleum sulphate) is separated. The following shall be added to the list of active substances: The following table shows the results of the analysis of the sodium salts in the feed additive: Two,1 g (3.7 mmol) of the A1 diastereomer is dissolved in 70 ml of 15% ethanol and after adding 13 ml of 1 n saline acid is heated for 48 h under return flow. After cooling, the remaining solution is filtered and the residue is mixed several times with ethanol. The combined ethanol solutions are compressed and the residue is absorbed in 50 ml of water and 50 ml of dichloromethane.The tetrahydrofuran is evaporated in the rotary evaporator and the remaining aqueous solution is lyophilized. The raw lyophilized solution is purified by RP 18 (solvent: acetonitrile/water 30/70). After freeze drying the product fractions, 850 mg (48 d.th) of (+) enantiomeric sodium salt (e.g. 1) is obtained. Other The mean of the measurements of the test chemical is calculated as the following: Other The specific rotation (EtOH): [α]D20=24,1° (c=1,0). Other From 1.5 g (2.6 mmol) of the B1 diastereomer, 800 mg (61,The concentration of the active substance in the solution is calculated as follows: Other The test shall be carried out on the test vessel.

Method variant B - Racetam separation with S- ((+) -phenylglycinol

(a) Manufacture of the diastereomeric phenylglycinolamides Other 418 g (0.88 mol) methyl erythro-E) -7[4- (4-fluorphenyl) -2,6-diisopropyl-5-methoxymethyl-pyrid-3-yl]-3,5-dihydroxyhept-6-enoate and 360 g (2.6 mol) S- ((+) phenylglycinol are dissolved in 1 l of absolute tetrahydrofuran and heated to 50 °C for 96 h. After distillation at room temperature, 1 l of water is added, the solution is set to pH 4 with 5 n of hydrochloric acid and extracted 3 times with 400 ml of ether each. The combined phases are washed with 400 columnar organic natrium chloride solution, dried with sodium sulphate and steamed. The waste product (500 g) is obtained by distillation in two portions of 350 g/l of crude oil (approximately 8 g/l) of petroleum (approximately 350 ml/l) of purified crude oil.The pre-purified raw product is separated into 7 portions of 50 g by means of a silica gel column (Büchi column, length 63 cm, 7 cm, silica gel 20 μ, sampling over 100 ml of sample groove). The diastereomer B2 was not isolated in its pure form but was recovered during the washing of the columns for possible future use as a raw material. (b) Manufacture of enantiomeric pure sodium salts (e.g. 1/2) 195 g (0.34 mol) of the diastereomeric pure amide A2 are dissolved in 1 l of ethanol p.A. and, after adding 1.2 l, 1 n of baking soda is heated overnight by backflow.After cooling to room temperature, the remaining solution is decanted and the oily residue is stirred three times with 50 ml of ethanol p.A. Each solution is combined and compressed. The residue is added to 500 ml of water and 500 ml of methyl chloride and the solution is set to pH 3.5 with 1 n of hydrochloric acid. Then the organic phase is separated and the aqueous phase is extracted three times with 400 ml of methyl chloride each. The combined organic phases are dried (Na2SO4) and compressed. The residue is dissolved in 100 ml of tetrahydrofuran and the solution is then diluted with 500 ml of water.5 the tetrahydrofuran is removed by rotational evaporation and the remaining aqueous solution is lyophilised. Other 142 g of raw lyophilisate is obtained, further purified and desalinated for desalination in 27 5 g and 2 3.5 g servings via a RP 18 column (length 40 cm, 3 cm, silica gel RP 18,30 μ, solvent acetonitrile/water 30/70); all product fractions are combined, the acetonitrile is removed by the rotary evaporator and the aqueous residue is lyophilised. The yield is 102 g (62,5% d.th.) of the (+) enantiomeric sodium salt (Bsp.1).

Claims (13)

1. Process for the preparation of substituted pyridyl-dihydroxy-heptenoic acid of the formula and its salts, if desired in an isomeric form, characterised in that

   [A] in the case of the racemic products, the corresponding racemic esters of the formula (II) in which

   R¹   represents C₁-C₄-alkyl or benzyl,

   are hydrolysed, or

   [B] in the case of the stereoisomerically homogeneous products first the racemic esters of the formula (II) are converted using the (+)- or (-)-enantiomeric amine of the formula (III) in which

   R²   represents C₁-C₄-alkyl which is optionally substituted by hydroxyl and

   R³   represents hydrogen, halogen or C₁-C₄-alkoxy,

   into the corresponding diastereomeric amides of the formula (IV)

   the diastereomeric amides are separated into the individual diastereomers by chromatography or crystallisation, and then the pure diastereomeric amides are hydrolysed to give the enantiomerically pure products.
2. Process according to Claim 1 for preparing compounds of the formula (I) in the erythro configuration.
3. Process according to Claim 1 for preparing the (+)-enantiomers of the formula (I).
4. Process according to Claim 1 for preparing the (+)-enantiomers in the erythro configuration.
5. Process according to Claim 1 for preparing the sodium, potassium, magnesium and ammonium salts.
6. Process according to Claim 1 for preparing sodium 3R,5S-(+)-erythro-(E)-7-[4-(4-fluorophenyl)-2,6-diisopropyl-5-methoxymethyl-pyrid-3-yl]-3,5-dihydroxy-hept-6-enoate.