NZ250085A - Use of dihydropyridinedicarboxylic acid esters as pharmaceuticals - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number £50085 Priority Daf(»): - Complete Specification Fifai: Claac (fl) Publlc«tton Dots: 2. A.!!®!..!®??..

P.O. Journal No: .'.hfcl.Hh NO DRAWINGS 2 5 Q f) .0 n ^ ^ J Patents Form 5 Under the provltloiw of Regi* »a«On 23 P) tbe — .... —~ •8j»oWtc*i<on has U vo ar,:.?-cu;eW au. 1^- N.Z. No.

MiiW ZKATiANT3 Patents Act 1953 COMPLETE SPECIFICATION USE OF N-ALKYLATED 1.4-DIHYDROPYRIDDJEDICARBOyYLld ACIPESTERS AS MEDICAMENTS. MEW COMPOUNDS AMD PROCESSES FOR THEIR PREPARATION We, BAYER AKTIENGESELLSCHAFT, a body of corporate organized under the laws of the Federal Republic of Germany, at Leverkusen, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement - 1 - (Followed by 1A) 250085 The present invention relates to the use of N-alkylated 1,4-dihydropyridinedicarboxylic acid esters, some of which are known, as haemorheological medicaments, new active compounds and processes for their preparation, in particular their use as medicaments in acute and chronic ischaemic disorders which are associated with microcirculation disorders. This action can occur both in the peripheral and in the cerebral vascular system.

It is known that 1,4-dihydropyridinedicarboxylic acid esters have a calcium antagonist or calcium agonist action, and can thus be employed as circulation-influencing agents US 3956341.

EP 240,828 describes hypotensive 1,4-dihydropyri-dines having haemorheological properties.

The use of hypotensive 1,4-dihydropyridines substituted by heterocycles as haemorheological agents has also been published in GB 2192132.

It has now been found that the N-alkylated 1,4-dihydropyridinedicarboxylic acid esters, some of which are known and some of which are new, of the general formula (I) (I) RaO - i A- NZ PATW--V O.TKIE 2? jiJM 1995 RECF.1V1D 1 J 00 in which R1 represents hydrogen, nitro, cyano, trifluoromethyl, trifluoromethoxy, halogen or methyl, R2 represents hydrogen, halogen, nitro, hydroxyl, trifluoromethyl or methyl, R3 represents hydrogen or cyano, or R2 and R3 together form a fused benzo ring, R4 and R3 are identical or different and represent straight-chain or branched alkyl having up to 8 carbon atoms, which is optionally substituted by alkoxy having up to 4 carbon atoms, R6 represents straight-chain or branched alkyl having up to 10 carbon atoms or represents cycloalkyl having 3 to 7 carbon atoms, surprisingly have a strong haemorheological action combined with neutral blood pressure behaviour and improve the circulation, in particular the microcirculation, and are thus suitable for use in the control of acute and chronic ischaemic disorders.

Compounds of the general formula (I) in which R1 represents hydrogen, nitro, trifluoromethyl, trifluoromethoxy, cyano, fluorine, chlorine, bromine or methyl, R2 represents hydrogen, fluorine, chlorine, bromine, nitro, hydroxyl, trifluoromethyl or methyl, R3 represents hydrogen or cyano, or R2 and R3 together form a fused benzo ring, 0 0 8 R* and Rs are identical or different and represent straight-chain or branched alkyl having up to 8 carbon atoms, which is optionally substituted by methoxy and R° represents straight-chain or branched alkyl having up to 4 carbon atoms, or cyclopropyl, are preferred for the control of acute and chronic ischaemic disorders.

Compounds of the general formula (I) in which R1 represents hydrogen, nitro, trifluoromethyl, trifluoromethoxy, cyano, fluorine, bromine, chlorine or methyl, R2 represents hydrogen, fluorine, chlorine, nitro, hydroxyl, trifluoromethyl or methyl, R3 represents hydrogen or cyano, or R2 and R3 together form a fused benzo ring, R* and R3 are identical or different and represent straight-chain or branched alkyl having up to 6 carbon atoms, which is optionally substituted by methoxy and R6 represents methyl, ethyl or cyclopropyl, are particularly preferred for the control of acute and chronic ischaemic disorders.

The compounds according to the invention show an unforeseeable, useful pharmacological action spectrum.

Combined with a neutral blood pressure behaviour 0 0 in a dose range up to at least 10 ing/kg i.v. and 30 mg/kg p.o., they increase the circulation,- in particular the microcirculation, by influencing the deformability of erythrocytes and also the inhibition of the activation and adhesion of leukocytes.

The blood pressure neutrality is determined in the following models, which are typical for dihydro-pyridinesi in SH rats after p.o. administration by measurement in the tail artery (Riva Rocci method) and in anaesthetized Wistar rats after i.v. administration (via a catheter inserted in the carotid artery). Blood-neutral compounds are designated as those which reduce the blood pressure by up to a maximum of 20% of the starting value in both test models at the dose indicated. The difference between the therapeutic dose and the blood pressure action occurring is at least a factor of 10, as a rule a factor of ^30, in particular fclOO.

They can therefore be employed for the production of medicaments for the treatment of acute and chronic ischaemic disorders, such as intermittent claudication, myocardial infarct, cerebral infarct and also reperfusion damage and shock.

The invention additionally relates to new 1,4-dihydropyridinedicarboxylic acid esters which are listed below: dibutyl 1,2,6-trimethyl-4-(l-naphthyl)-1,4-dihydro-pyridine-3,5-dicarboxylate diethyl 1,2,6-trimethyl-4-(4-fluorophenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate dipropyl 1,2,6-trimethyl-4- (2-cyanophenyl) -1,4-dihydro- 0 0 pyridine-3,5-dicarboxylate dibutyl 1,2,6-trimethyl-4-(4-nitrophenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate dimethyl 1,2,6-trimethy1-4-(4-trifluoromethylphenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate methyl propyl 1,2,6-trimethyl-4-(4-trifluoromethylphenyl )-1,4-dihydro-pyridine-3,5-dicarboxylate methyl isopropyl 1,2,6-trimethyl-4-(4-trifluoromethylphenyl )-1,4-dihydro-pyridine-3,5-dicarboxylate methyl 1,2-dimethylpropyl 1,2,6-trimethyl-4- (4-trif luoromethylphenyl )-1,4-dihydro-pyridine-3,5-dicarboxylate methyl 2-methoxyethyl 1,2,6-trimethyl-4-(4-trifluoromethylphenyl )-1,4-dihydro-pyridine-3,5-dicarboxylate dimethyl 1,2,6-trimethyl-4-(3-fluorophenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate dipropyl 1,2,6-trimethyl-4-(3-methylphenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate dimethyl 1,2,6-trimethyl-4-(4-bromophenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate dipropyl 1,2,6-trimethyl-4-(4-bromophenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate dibutyl 1,2,6-trimethyl-4-(4-bromophenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate dipropyl 1,2,6-trimethyl-4-(4-cyanophenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate diethyl l-cyclopropyl-2,6-dimethyl-4-( 3-trifluoromethylphenyl )-1,4-dihydro-pyridine-3,5-dicarboxylate dimethyl l-ethyl-2,6-dimethyl-4-(4-trifluoromethylphenyl )-1,4-dihydro-pyridine-3,5-dicarboxylate dimethyl l-cyclopropyl-2,6-dimethyl-4-(4-trif luoromethyl- 2 5 Q q p phenyl) -1,4-dihydro-pyridine-3,5-dicarboxylate diethyl l-cyclopropyl-2,6-dimethyl-4-(4-trifluoromethylphenyl ) -1,4-dihydro-pyridine-3,5-dicarboxylate diisopropyl 1,2,6-trimethyl-4-(4-trifluoromethylphenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate dimethyl 1,2,6-tr ijnethyl-4- (4-methyl-3-nitrophenyl) -1,4-dihydro-pyridine-3,5-dicarboxylate dipropyl 1,2,6-trimethyl-4-(4-methyl-3-nitrophenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate dibutyl 1,2,6-trimethyl-4-(4-methyl-3-nitrophenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate diethyl 1,2,6-trimethyl-4-(4-methyl-3-nitrophenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate diethyl 1,2,6-trimethyl-4-(3-chloro-4-nitrophenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate dimethyl 1,2,6-trimethyl-4-(4-chloro-3-trifluoromethylphenyl )-1,4-dihydro-pyridine-3,5-dicarboxylate dimethyl 1,2,6-trimethyl-4-(4-methyl-3-trifluoromethylphenyl ) -1,4-dihydro-pyridine-3,5-dicarboxylate dimethyl 1,2,6-trimethyl-4-(3-hydroxy-4-nitrophenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate dimethyl l-cyclopropyl-2,6-dimethyl-4-(4-trifluoro-methoxyphenyl) -1,4-dihydro-pyridine-3,5-dicarboxylate diethyl l-cyclopropyl-2,6-dimethyl-4- (4-trif luoromethoxy-phenyl) -1,4-dihydro-pyridine-3,5-dicarboxylate isopropyl 2-methoxyethyl 1,2,6-trimethyl-4-(4-trifluoromethylphenyl )-1,4-dihydro-pyridine-3,5-dicarboxylate diethyl 1,2,6-trimethyl-4-(4-trifluoromethylphenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate methyl ethyl l-cyclopropyl-2,6-dimethyl-4-(4-trifluoro- 250085 methylphenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate propyl 2-methoxyethyl l-cyclopropyl-2,6-dimethyl-4-(4-trifluoromethylphenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate isopropyl 2-methoxyethyl l-cyclopropyl-2,6-dimethyl-4-(4-trifluoromethylphenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate diethyl l-cyclopropyl-2,6-dimethyl-4- (4-f luorophenyl) -1,4-dihydro-pyridine-3,5-dicarboxylate dimethyl l-cyclopropyl-2,6-dimethyl-4-(4-fluorophenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate propyl butyl l-cyclopropyl-2,6-dimethyl-4-(4-trif luorophenyl )-1,4-dihydro-pyridine-3,5-dicarboxylate butyl methyl l-cyclopropyl-2,6-dimethyl-4-( 4-trif luoromethylphenyl )-1,4-dihydro-pyridine-3,5-dicarboxylate ethyl propyl l-cyclopropyl-2,6-dimethyl-4-(4-trifluoromethylphenyl )-1,4-dihydro-pyridine-3,5-dicarboxylate butyl ethyl l-cyclopropyl-2,6-dimethyl-4 - (4-trif luoromethylphenyl )-1,4-dihydro-pyridine-3,5-dicarboxylate ethyl isopropyl l-cyclopropyl-2,6-dimethyl-4-(4-tri-f luoromethylphenyl) -1,4-dihydro-pyridine-3,5-dicarboxylate.

Particularly preferred compounds are the 1,4-dihydropyridinedicarboxylic acid esters whose phenyl ring is monosubstituted in the para-position by fluorine, bromine or by the CF3 group.

Very particularly preferred compounds are the followingi dimethyl 1,2,6-trimethyl-4- (4-bromophenyl) -1,4-dihydro-pyridine-3,5-dicarboxylate (Ex 13) Q Q ;q diethyl l-cyclopropyl-2,6-dimethyl-4-(4-trifluorc. -»thyl-phenyl)-l,4-dihydro-pyridine-3,5-dicarboxylate (Ex 19) dimethyl l-cyclopropyl-2,6-dimethyl-4-(4-trifluoromethylphenyl) -1,4 -dihydro-pyridine- 3, 5-dicarboxylate (Ex 18.). dimethyl 1,2,6-trimethyl-4-(4-trifluoromethylphenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate (Ex 3) methyl 1,2-dimethylpropyl 1,2,6-trimethyl-4- (4-trif luoromethylphenyl )-1,4-dihydro-pyridine-3,5-dicarboxylate.

Some of the compounds according to the invention exist in stereoisomeric forms which behave either as image and mirror image (enantiomers) or which do not behave as image and mirror image (diastereomers). The invention relates both to the antipodes and to the racemic forms and the diastereomer mixtures. The racemic forms can be separated into the stereoisomerically uniform components in a known manner, just like the diastereomers (compare E.L. Eliel, Stereochemistry of Carbon Compounds, McGraw Hill, 1962). ing to the invention and the new compounds can be prepared by a process in which [A] benzylidene compounds of the general formula (II) The compounds of the general formula (I) accord- (II) /CTs CO2R4' in which H3C-CO o 0 8 5 R1', R2', R3' and Rv have the abovementioned meaning of R1, R2, R3 and R* and additionally include the respective scope of meaning of the new compounds listed above, are either first reacted with /3-aminocrotonic acid esters of the general formula (III) in which R3' has the abovementioned meaning of R3 and additionally includes the scope of meaning of the new compounds listed above, in inert solvents and in a last step the NH function is alkylated by a customary method, the compounds of the general formula (II) are directly reacted, if desired in the presence of Lewis acids such as titanium tetrachloride, with compounds of the general formula (Ilia) (III) or (Ilia) in which R3' has the abovementioned meaning, R6' has the abovementioned meaning of R8 and 2500 8 5 additionally includes the scope of meaning of the new compounds listed above, or [B] aldehydes of the general formula (IV) (IV) cho in which R1', R2' and R3' have the meaning indicated under process [A], are first reacted with /9-ketocarboxylic acid esters 10 of the general formulae (V) and (Va) f5'-o,c-ch2 a. 2 | h2c-co2-f4 <?° (V) and CO (Va) H3C I 3 ch3 in which R*' and R3' likewise have the meaning indicated under process [A] and then are either reacted directly with amines or the corresponding amine hydrochlorides of the general formula (VI) ejn-r8' (vi) 250085 in which R8' has the meaning indicated. above under process [A] or are first ring-closed with ammonia in organic, if appropriate inert, solvents according to a customary method and in a last step alkylated by the method mentioned above, and in the case of the enantiomerically pure esters, the enantiomerically pure carboxylic acids eare first prepared and these are esterified with the appropriate alcohols by a customary method, if desired by means of a reactive acid derivative.

The process, according to the invention, for the preparation of the new compounds can be illustrated by way of example by the following equation; 0 085 CA3 cf- 2 H-,C-C»CH-CO,CoH 2v"2n5 NHCH- CHO CF- TiCl4 H5C2O2 'C02c2h5 CH- CB] 0 0 Description of Processes Suitable solvents are water, or organic solvents which do not change under the reaction conditions. These preferably include alcohols such as methanol, ethanol, propanol, Isopropanol, ethers such as diethyl ether, dioxane, tetrahydrofuran, glycol monomethyl ether or glycol dimethyl ether, or amides Buch as dimethylform-amide, dimethylacetamide or hexamethylphosphoric tri-amide, or glacial acetic acid, dimethyl sulphoxide, acetonitrile or pyridine.

The reaction temperatures can be varied within a relatively wide range. In general, the reaction is carried out between +10*C and +150#C, preferably between +20"C and +100°C, in particular at the boiling point of the respective solvent.

The reaction can be carried out at normal pressure, but also at elevated or reduced pressure. In general, the reaction is carried out at normal pressure.

When carrying out process variants A and B according to the invention, any desired ratio of the substances participating in the reaction can be used. In general, however, molar amounts of the reactants are used. The isolation and purification of the substances according to the Invention is preferably carried out by removing the solvent by distillation in vacuo and recrys-tallizing the residue, which may only be obtained in crystalline* form after ice-cooling, from a suitable solvent. In some cases, it may be necessary to purify the compoavKls according to the invention by chromatography.

The ylidene compounds of the general formula (II) 250085 are known in some cases or can be prepared by known methods [compare H. Dornow and W. Sassenberg, Liebigs Ann. Chem. 602, 14 (1957)].

The aldehydes of the general formula (IV) 5 employed as starting materials are known or can be prepared by known methods US 3789444; US 3956395; , T.D. Harris, G.F. Roth, J. Org. Chem. 2004 (1979); W.J. Dale, H.E. Hennis, J.

Am. Chem. Soc. 7fi, 2543 (1956); Chem. Abstr. 51, 13929 10 (1963)].

The l-ketocarboxylic acid esters of the general formulae (V) and (Va) employed as starting materials are known or can be prepared by known methods [D. Borrmann in Houben Weyl's "Methoden der organischen Chemie" (Methods 15 of Organic Chemistry) Vol. VII/4, 230 (1968); Y. Oikawa, K. Sugano, O. Yonemitsu, J. Org. Chem. 11/ 2087 (1978)].

The ^-aminocrotonic acid esters of the general formulae (III) and (Ilia) employed as starting materials are known or can be prepared by known methods 20 F.A. Glickman, A.C. Cope, J. Am. Chem. Soc. £2, 1017 (1945)].

The compounds of the general formula (VI) are also known.

Examples of reactive acid derivatives which may 25 be mentioned are: activated esters, hydroxysuccinimide esters, acid imidazolides, acid halides, mixed anhydrides or reaction in the presence of cyclohexylcarbodiimide.

Examples of alkylating agents which can be employed in the process are (Cj-Cg) -alkyl halides, 30 sulphonic acid esters or substituted or unsubstituted n.z. patent OFFICE 27 JUN1995 003 (Cj,-CQ)-dialkyl sulphates, preferably methyl Iodide, p-toluenesulphonic acid esters or dimethyl sulphate.

The alkylation is carried out in the above-mentioned solvents at temperatures from 0*C to +150 *C, preferably at room temperature up to +100 "C at normal pressure.

Activating reagents which may be mentioned by way of example for the preparation of the reactive acid derivatives are, in addition to the inorganic halides such as thionyl chloride, phosphorus trichloride or phosphorus pentachloride, or carbonyldiimidazole, carbo-diimides such as cyclohexylcarbodiimide or 1-cyclohexyl-3-[ 2- (N-methyl-morpholino)ethyl]carbodiimide-p-toluene-sulphonate or N-hydroxyphthalimide or N-hydroxybenzo-triazole in the presence of dicyclohexylcarbodiimide.

Suitable solvents for the reaction with the appropriate alcohols are the abovementioned solvents with the exception of the alcohols.

The diastereomer pairs are separated by known methods such as column chromatography, fractional crystallization or Craig partition [for Craig partition see, for example, "Verteilungsverfahren im Laboratorium" (Partition Methods in the Laboratory), E. Hecher, Verlag Chemie GmbH, Weinheim, Bergstr. (1953)].

The new and the known compounds according to +.he invention show an unforeseeable, useful pharmacological action spectrum.

The following in vitro and in vivo tests show the interesting actions of the compounds according to the invention. a 5 o q a I) Erythrocyte function The deformability of erythrocytes plays an essential role in the origin and course of acute or chronic ischaemic disorders. It determines the viscosity of the blood and thus its distribution in the microcirculation. The tests used detect various determinantss Test a) measures the calcium permeability (*3 Ca) by blockade of the ATPases by Na ortho-vanadate. As a result, calcium can accumulate in the erythrocytes. A consequence is a reduced flexibility. EDS0 values (mol/1) for the inhibition of calcium influx are given for test a).

Test b) detects the antihaemolytic action of the substances (ED30, mol/1). in this test, calcium-laden erythrocytes are forced through small pores under high shearing stresses, so that haemoglobin is released as a result of their haemolysis and measured. The reduction in haemoglobin release is the measured quantity.

Test c) detects the filterability of calcium-laden erythrocytes through 5 pra pores (ED30, mol/1). In this test, the membrane flexibility plays a role under small force gradients.

Test d) detects the viscosity of erythrocyte suspensions in glass capillaries (25 m® diameter) at low shearing stresses occurring in areas of vessels behind a stenosis. As a result of increasing the extracellular calcium, the viscosity increases.

The table gives the percentage improvement in he viscosity relative to damage - 100% at a test dose o£ 10 ng/ml. b 0 Q a) Calcium permeability of erythrocytest After blockade of the membrane-immobilized ATPases by Na ortho-vanadate (0.75 mM), the calcium permeability is measured (° Ca method). Accumulation of calcium reduces the flexibility of the erythrocytes.

Tflfrlg It 3 x 10"6 13 x 10"6 21 x 10"' 27 "6 . b) Antihaemolvtlc action of erythrocytes 15 Normal erythrocytes become haemolytic under high shearing stresses. The haemolysis of calcium-laden cells is particularly pronounced. This measure of mechanical stability is used for substance characterization. The measured quantity is the concentration 20 of free haemoglobin in the medium. c 5 0 0 8 Table lit Example No. EDS0 of the antihaemolytic action (mol/1) 2 '7 13 x "7 x "' 21 x "7 22 x "7 26 3 x "# 27 x "' . c) ratmign g£ gmhrpyytftg Filtration of erythrocytes through 5 pm sieve 15 pores is an established method for the determination of the deformability of erythrocytes. The cells are sheared in normal buffer for 30 min so that the calcium concentration increases intracellularly and the flexibility is reduced.

Table III: Ex. No. EDS0 improvement in the flexibility compared to damage to control (mol/1) 1 x "' 3 x "8 26 x '8 28 x "8 . d) Yiffggeity In qlflgg gapillarlqg The biophysical interactions of erythrocytes 00 8 relevant to the circulation can be investigated in glass capillaries (diameter 20-30 jim). The resulting viscosity depends on the condition of the cells. In the case of calcium loading, the viscosity increases. The percentage improvement in the viscosity relative to the damaged but untreated control is given at 0.7 Pa. The test dose is 10~s g/ml.

II) Leukocyte function The microcirculation can be directly observed in the hamster cheek pouch model. Measured quantities are leukocyte adhesion and also vessel diameter and erythrocyte velocity. The adhesion was quantified under ischaemic and non-ischaemic experimental conditions. Under non-ischaemic conditions, the adhesion is quantified in the area of small venules, under ischaemic conditions (10 min circulation stop) the adhesion is quantified in small arterioles. The results of the control experiments are given relative to 100%. 0.1 mg/kg i.v. is in each case chosen as the Table IVt Example No Effect (%) 3 13 14 17 18 24 143 120 206 75 62 208 226 0 0 test dose, the results are decreases in % of the control.

Table V» Example Mo. Non-ischaemic Ischaemic control control - 100 % - 100 % 3 63 % 31 % 6 50 % 56 4 9 70 % 36 % 18 54 % 32 % 19 61 % 34 % III) Blood pressure The clinical state of knowledge shows that anti-ischaemic actions of dihydropyridines are frequently masked by vasodilatation. It was therefore the aim to find blood pressure-inactive DHPs (i.e. difference between haemorheological action and blood pressure-reducing action 2 10). The following table shows the doses at which a blood pressure reduction occurs in the case of p.o. administration (SH rats) or i.v. administration (anaesthetized Wistar rats).

Table VI t Example Pt<?t fmq/Hg) i.v. rmo/kgy 3 >30 >10 6 >30 >10 9 >30 >10 18 >30 > 10 19 > 100 > 10 » 0 0 0 H The table shows that, in comparison to model II, the difference between the therapeutic action and blood pressure action (i.v.) is at least 100.

The new active compounds can be converted in a known manner into the customary formulations, such as tablets, coated tablets, pills, granules, aerosols, syrups, emulsions, suspensions and solutions, using inert, non-toxic, pharmaceutically suitable excipients or solvents. In this connection, the therapeutically active compound should in each case be present in a concentration of about 0.5 to 90% by weight of the total mixture, i.e. in amounts which are sufficient in order to achieve the dosage range indicated.

The formulations are prepared, for example, by extending the active compounds with solvents and/or excipients, if appropriate using emulsifiers and/or dispersants, where, for example, in the case of the use of water as a diluent, organic solvents can optionally be used as auxiliary solvents.

Administration is carried out in a customary manner, preferably orally or parenterally, in particular periingually or intravenously.

In the case of parenteral use, solutions of the active compounds using suitable liquid excipient materials can be employed.

In general it has proved advantageous on intravenous administration to administer amounts of about 0.001 to 1 mg/kg, preferably about 0.01 to 0.5 mg/kg of body weight to achieve effective results, and on oral administration the dosage is about 0.01 to 20 mg/kg, 2500 preferably O.l to 10 mg/kg of body weight.

In spite of this, it may be necessary to deviate from the amounts mentioned, in particular depending on the body weight or the type of administration route, on individual behaviour towards the medicament, the nature of its formulation and the point in time or interval at which administration takes place. Thus, in some cases it may be sufficient to manage with less than the above-mentioned minimum amount, while in other cases the upper limit mentioned must be exceeded. In the case of the administration of larger amounts, it may be advisable to divide these into several individual doses over the course of the day.

Preparation Examples Example 1 Diethyl 1,2,6-trimethyl-4-(4-fluorophenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate F 2.78 g (0.008 mol) of diethyl 2,6-dimethyl-4-(4-fluorophenyl) -1,4-dihydro-pyridine-3,5-dicarboxylate are dissolved in 25 ml of 1,2-dimethoxyethane, and 0.30 g (0.01 mol) of 80% strength sodium hydride and, after 30 *5 0 0 8 mln, 1.43 g (0.01 mol) o£ methyl iodide are added. The mixture is stirred at room temperature for 3 hours, neutralized with dilute hydrochloric acid and evaporated in vacuo. The residue is purified by chromatography, .on silica gel (methylene chloride).

Yield: 1.85 g (63.9% of theory).

Melting point* 90 - 92*C.

Example 2 Dimethyl 4- (3-f luorophenyl) -1,2,6-trimethyl-l, 4 - dihydro-pyridine-3,5-dicarboxylate A mixture of 3.84 g (0.03 mol) of 3-fluorobenz-aldehyde, 7.04 g (0.06 mol) of methyl acetoacetate and 2.07 g (0.03 mol) of methylamine hydrochloride in 20 ml of pyridine is stirred under reflux for 5 hours. After removing the pyridine by distillation, the mixture is partitioned between water and methylene chloride, and the organic phase is washed with water, dried over sodium sulphate and evaporated. The residue is recrystallized from methanol.

Melting point* 117-118*C Yields 6.14 g (61.4% of theory) i 0o fixflropl? 3 Dimethyl 1,2,6-triraethyl-4- (4-trif luoromethylphenyl) -1,4-dihydro-pyridine-3,5-dicarboxylate A mixture of 5.22 g (0.03 mol) of 4-trifluoro-methylbenzaldehyde, 7.04 g (0.06 mol) of methyl aceto-acetate and 2.07 g (0.03 mol) of methylamine hydrochloride in 20 ml of pyridine is stirred under reflux for 5 hours. After removing the pyridine by distillation, the mixture is partitioned between water and methylene chloride, and the organic phase is washed with water, dried over sodium sulphate and evaporated. The residue is recrystallized from methanol.

Melting points 154 - 155"C Yields 7.88 g (68.5% of theory) The examples shown in Tables 1 and 2 were prepared in analogy to the procedure of Example 3. 24 - R5 1 Example Ho. r1 K» Ul r5' m.p.*C Tleld (% of theory) -C2H5 90-92 63.9 /V) Cji Q o CO cn Table 2t Ex. NO. R1' R3' R4' i K> o\ l 5 6 7 8 9 ! h cn -c3h7 hog h -c^h^ cf3 h -c3h7 cfg h -ch(ch3>2 cf3 h -ch-ch(ch3)2 ch3 cf3 h -<ch2)2-och3 r5' ra.p.'C Yield (% of theory) -C3H7 Oil 19,4 -C4H9 81-84 62.7 -CH3 76-78 -CH3 86-88 ■CH3 54-57 /v CH3 71-73 o? o CD Ol *S 0 0 3.X? Dipropyl 4-(4-bromophenyl)-1,2,6-trimethyl-l,4-dihydro-pyridine-3,5-dicarboxylate Br A solution of 6.22 g (0.02 mol) of propyl 2-(4-bromobenzylidene)acetoacetate and 3.14 g (0.02 mol) of propyl 3-methylamino-crotonate in 25 ml of 2-butanol is stirred under reflux for 10 hours. The mixture is then concentrated in vacuo, and the precipitate formed in the cold is filtered off with suction. After recrystalliza-tion from propanol, 5.32 g (59.1% of theory) of melting point 97-99*C are obtained.

The compounds shown in Table 3 can be prepared analogously to Example 11. 27 - Table 3i # R5' R6' a.p.'C Yield (% of theory) c3h7 -ch ch3 -ch c4h9 -ch c3h7 -ch c2H5 ch3 ch3 A -c2h A '3 67-68 23,3 '3 163-167 59.5 '3 66-68 36.5 [3 116-119 45.7 i .112-114 22.4 H5 119-129 .5 »o Or 137-138 .6 0 Continuation of Table 3 Ex. No. . R1' R2' R4' 19 -cf3 h "c2h5 -cf3 h -ch(ch3)2 21 -ch3 -no2 -ch3 22 tn z u 1 -no2 ~C2H5 23 -CHg -ho2 -c3h7 24 -ch3 -no2 -c4h9 -no2 ci -C2«5 26 -ci -cf3 -ch3 27 -ch3 -cf3 -ch3 28 -no2 -oh -ch3 29 -ocf3 h -ch3 -ocf3 h -C2"5 31 -cf3 h -ch2-ch2-och 31a (♦)-Enantiomer [a] 10.3 (( 589 31b (-)-EnanLioiner C<x] -101 (< 589 r5' r6' m.p.'C Yield (% of theoryf" A -C2H5 /\ 111-113 15.5 CH(CH3)2 -CH3 106-108 49.1 -CH3 -CHg 116-118 66.1 ~C2H5 ~CH3 97-98 60.1 -C3H7 -CH3 94-96 41.3 -C4H9 -CH3 89-90 45.4 -C2H5 -CH3 128-130 60.1 -CH3 -CH3 122-124 63.8 -CH3 -CH3 103-105 4.83 -CH3 -CH3 187-189 62.6 -CH3 A 77-78 13.2 A A -CH(CH3)2 -CH3 Oil 74.3 -C2H5 /\ 108-109 18.5 1 in CHC13) 1 in CHC13) *>0 or o CJJ 0 0 8 5 Example 32 Diethyl 1,2,6-trimethyl-4-(4-trifluoromethylphenyl)-1,4-dihydro-pyridine-3,5-dicarboxylate 0.55 ml (5 mmol) of titanium tetrachloride, then 1 ml (10 mmol) of piperidine are added under nitrogen protection to 20 ml of toluene and the mixture is stirred for 5 min. After the dropwise addition of 2.9 g (20 mmol) of methyl 3-methylaminocrotonate, 1.36 ml (10 mmol) of 4-trifluoromethylphenylbenzaldehyde are added and the mixture is stirred at room temperature for 3 hours. For working up, 100 ml of 5% strength hydrochloric acid are added and the organic phase is taken up with ethyl acetate, and the ethyl acetate solution is washed successively with 5% hydrochloric acid and with sodium bicarbonate solution. After drying the ethyl acetate solution over sodium sulphate, evaporating and stirring the residue in n-heptane, 1.7 g (41.4% of theory) are obtained.

Melting point* 98*C 0 08 Example 33 Methyl ethyl l-cyclopropyl-2,6-dimethyl-4-(4-trifluoromethylphenyl )-1,4-dihydro-pyridine-3,5-dicarboxylate ide are added to a solution of 3.9 g (0.03 mol) of ethyl acetoacetate and 8.16 g (0.03 mol) of methyl 2-(4-tri-fluoromethylbenzylldene)acetoacetate in 50 ml of pyridine and the mixture is heated under reflux for 5 hours. The reaction product is concentrated in vacuo, the residue is taken up in methylene chloride and water, the aqueous phase is separated off, and the methylene chloride solution is dried over sodium sulphate and evaporated. The residue is purified by chromatography on silica gel using methylene chloride as the solvent. After dissolving and crystallizing the product from n-heptane, 2.2 g (17.3% of theory) are obtained.

Melting point: 110*C The compounds shown in Table 4 can be prepared in analogy to the procedure of Examples 32 and 33.

H3C02 «3 3.6 g (0.039 mol) of cyclopropylamine hydrochlor- 0 0 8 Tflfrle 4f 34 -cfg -c4h9 -C3H 7 62 -cf3 -<ch2)2och3 -C3H7 Oil 36 -f -CHg -CHg 140 37 -f -C2H5 -c2hs 79 38 -cf3 -C4H9 -ch3 Oil 39 -cf3 -C3H 7 -C2H5 55-57 40 -cf3 -C4H9 -c2h5 55-60 41 -cf3 -c2h5 -ch(ch3)2 96 The examples shown in Table 5 were prepared in analogy to the procedures of Examples 1, 3 and 11.

T«M* 5? R5' r6' a.p.'C Yield (% of theory) -C2Hs -CM3 116-118 78 /NO CJI O O CD Oj Table 5» Continuation Example Rl • R2 • R4 * No. 43 -f h -ch3 44 -f h c2h5 45 -cf3 h -<ch2)2och3 46 -cf3 h -(ch2)2och3 47 -f -cf3 -ch3 48 -F -CF3 "c2H5 49 -cf3 h -ch3 50 -cf3 h "c2H5 51 -f -cf3 -ch3 • • r5* r6' D.p."c Yield (% of theory) -ch(ch3)2 -ch3 92-94 73 -ch(ch3)2 -ch3 Oil 73 -C2"5 -ch3 56-57 57 CH2-CH(CH3)2 -ch3 55-60 68 -ch3 -ch3 133 59 A -c2h5 61 19 CH2-CH(CH3)2 -CH3 68 58 CH2-CH(CH3>2 -CH3 63 75 -CH3 /\ 118 27 Ol o 0 CO 01 Table 5f Continuation Example No. >1 * »2' j4 ' 52 53 54 55 -f -OCF* -OCFr -CFr -cf; h h h c2»5 -(CH2)2OCH3 -C2"5 -(CH2)2OCH3 U) Ul 56 57 58 59 60 -CN -cf. •cn -cf, -f h h h h -cf- ■ch- -ch2ch(ch3)2 c2h5 -ch2ch(ch3)2 • -(ch2)2och3 r5 ' rfe ' ib.p- *C Yield (% of theory) ~c2h5 -ch3 83 63 CH2-CH(CH3)2 -ch3 62 21 -ch2ch(ch3)2 -ch3 73 19 -ch2-ch(ch3)2 -ch3 Oil 45 enant. «20 : -11.1 589 (chc13). C: 0.85 -ch(ch3)2 -ch3 122 50 -ch2ch(ch3)2 1 o X U) 68 45 -ch(ch3)2 -ch3 106-107 50 -ch2ch(ch3)2 A \ 92 11 -ch(cii3)2 -ch3 82-83 r>o CJl O o GO CJl Table 5i Continuation Exanple R1 R2 r4 No. 61 -cf3 h ~c6h13 62 -cf3 h -c4h9 63 -cf3 h ~c5h11 64 -ci h -ch3 65 -ci h -ch3 ' r6 * ».p.*C Yield (% of theory) -ch3 -ch3 64-65 36 -ch3 -ch3 71-73 28 -ch3 1. o x 75-77 13 -ch3 -c2«5 143 21 -ch3 -ch3 181 19 IV Cjn o o CD CJl

Claims (5)

WHAT WE CLAIM IS: 250085

1. Use of N-alkylated 1,4-dihydropyridines of the general formula (I) R'O (I) in which R1 represents hydrogen, nitro, cyano, trifluoromethyl, trifluoromethoxy, halogen or methyl, R2 represents hydrogen, halogen, nitro, hydroxyl, trifluoromethyl or methyl, R3 represents hydrogen or cyano, or r2 and R3 together with the carbon atoms to which they are attached form a fused benzo ring, R* and R3 are identical or different and represent straight-chain or branched alkyl having up to 8 carbon atoms, which is optionally substituted by alkoxy having up to 4 carbon atoms, R* represents straight-chain or branched alkyl having up to 10 carbon atoms or represents cycloalkyl having 3 to 7 carbon atoms, having neutral blood pressure properties in the preparation of circulation-promoting medicaments.

2. Use of compounds according to Claim 1, 250085 characterized in that dihydropyridines of the general formula (I) according to Claim 1 are employed, in which R1 represents hydrogen, nitro, trifluoromethyl, tri-fluoromethoxy, cyano, fluorine, chlorine, bromine or methyl, R2 represents hydrogen, fluorine, chlorine, bromine, nitro, hydroxyl, trifluoromethyl or methyl, R3 represents hydrogen or cyano, or Ra and RJ together with the carbon atoms to which they are attached form a fused benzo ring, R* and R9 are identical or different and represent straight-chain or branched alkyl having up to 6 carbon atoms, which is optionally substituted by methoxy and R8 represents straight-chain or branched alkyl having up to 8 carbon atoms, or cyclopropyl.

3. Use of compounds of the general formula (I) according to Claim 1 in the production of medicaments for the control of acute and chronic ischaemic disorders.

4. Use of compounds of the general formula (I) according to Claim 1, in which R1 represents fluorine, bromine or CP3, R2 and R3 in each case denote hydrogen, and R*, R5 and R8 have the meaning mentioned in Claim 1, in the production of medicaments for the treatment of intermittent claudication, myocardial infarct, cerebral infarct and reperfusion damage. n.z. patent office 27 JUN1995 RECEIVED - 38 - V . I 250085

5- Use of compounds according to claim r .. k , . g to claim 1 substantially as herein describe „ described or exemplified. BAYER AKT1ENGESELLSCHAFT By their Attorneys HENRY HUGHES N.2.PATBNTOPF5CE 39 27 JUN1995 RECEIVD