1,4-Dihydropyiridine derivative, a process for preparing the same, a pharmaceutical composition as well as the use thereof.

0001The present invention relates to novel 1,4-dihydropyridine derivatives having an excellent pharmacological action.

0002Particularly, it relates to a 1,4-dihydropyridine derivative represented by the general formula: <chemistry id="chem0001" num="0001"><img file="EP0197488A2_D0001.tif" /></chemistry>wherein R' stands for an aryl or heteroaryl group which may be substituted with a lower alkyl, lower alkoxy, halogen, nitro, trifluoromethyl or cyano group or may form an alkylenedioxy group together with adjacent carbon atom constituting an aryl group; R² stands for a lower alkoxy group, a group represented by the general formula: <chemistry id="chem0002" num="0002"><img file="EP0197488A2_D0002.tif" /></chemistry>(wherein n stands for a positive number of 2 to 6 and W stands for a hydrogen or halogen atom or a lower alkoxy group) or a group represented by the general formula: <chemistry id="chem0003" num="0003"><img file="EP0197488A2_D0003.tif" /></chemistry>(wherein R⁶ stands for a hydrogen atom or a nitro group and X stands for a hydrogen or halogen atom or a lower alkoxy group); <ul id="ul0001" list-style="none"><li>R³ stands for a hydrogen atom or a 4-p-(fluorobenzoyl)-1-piperidyl group, or alternatively, R² and R' may together form a ring;</li><li>R⁴ stands for a hydrogen atom, a lower alkyl or phenylaklyl group or a group represented by the formula -CH2-L [wherein L stands for a group of - OR⁷ (wherein R' stands for a lower alkyl group) or a group represented by the general formula: <chemistry id="chem0004" num="0004"><img file="EP0197488A2_D0004.tif" /></chemistry>(wherein m stands for a positive number of 0 to 5 and Y stands for a hydrogen or halogen atom or a lower alkoxy group);</li><li>R^S stands for a lower alkyl or lower alkoxy lower alkyl group, a group represented by the general formula: <chemistry id="chem0005" num="0005"><img file="EP0197488A2_D0005.tif" /></chemistry>(wherein p stands for a positive number of 1 to 6 and Z stands for a hydrogen or halogen atom or a lower alkoxy group) or a group represented by the general formula: <chemistry id="chem0006" num="0006"><img file="EP0197488A2_D0006.tif" /></chemistry>(wherein q stands for a positive number of 1 to 6 and M stands for a hydrogen or halogen atom or a lower alkoxy group),</li><li>or a pharmaceutically acceptable salt thereof, a process for the preparation thereof and a medicine containing it as an active principle.</li></ul>

0003In the above definition of the compound (I) according to the present invention, the term "lower alkyl" refers to straight-chain or branched alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, 1-methylpropyl, tert-butyl, n-pentyl, 1-ethylpropyl, isoamyl or n-hexyl group. Further, the terms "lower alkoxy group" and "lower alkoxy lower alkyl group" refer to groups each derived from the above lower alkyl groups.

0004Representative examples of the aryl group in the definition of R' include phenyl and naphthyl groups.

0005R² and R' may together form a ring. Particularly, the present invention includes compounds represented by the formula: <chemistry id="chem0007" num="0007"><img file="EP0197488A2_D0007.tif" /></chemistry>or <chemistry id="chem0008" num="0008"><img file="EP0197488A2_D0008.tif" /></chemistry>

0006The "halogen" in the definition of W, X, Y, Z or M refers to fluorine, bromine, iodine and chlorine.

0007The compound (I) of the present invention can be converted into its acid addition salt by reacting it with a pharmaceutically acceptable inorganic ,or organic acid. Examples of the inorganic acid include hydrochloric, hydrobromic, hydroiodic, sulfuric and phosphoric acids, while those of the organic acid include maleic, fumaric, succinic, acetic, mal- onic, citric, benzoic, oxalic, and methanesulfonic acids.

0008The compound (I) of the present invention is thought owing to its structural characteristics to be present as optical isomers based on the asymmetric carbon atom at position 3 of the 1,4-dihydropyridine ring. The present invention includes all of the isomers.

0009The compound of the present invention can be prepared by various methods, among which representative methods are as follows: <ul id="ul0002" list-style="none"><li>Reparation method A [for compounds represented by the formula (1) wherein R⁴ is H]</li></ul>

0010The following three compounds are reacted to obtain an objective compound. <ul id="ul0003" list-style="none"><li>1 A compound represented by the general formula (II) R' -CHO (II) wherein R' stands for an aryl or heteroaryl group which may be substituted with a lower alkyl, lower alkoxy, halogen, nitro, trifluoromethyl or cyano group or may form an alkylenedioxy group together with an adjacent carbon atom constituting an aryl group.</li></ul>

0011Examples of the compound include benzaldehyde derivatives represented by the general formula: <chemistry id="chem0009" num="0009"><img file="EP0197488A2_D0009.tif" /></chemistry>wherein A and B may be the same or different from each other and each stands for a lower alkyl, lower alkoxy, halogen, nitro, trifluoromethyl or cyano group or the both may together form an alkylenedioxy group, and compounds represented by the formula: <chemistry id="chem0010" num="0010"><img file="EP0197488A2_D0010.tif" /></chemistry>or <chemistry id="chem0011" num="0011"><img file="EP0197488A2_D0011.tif" /></chemistry><ul id="ul0004" list-style="none"><li>2 An acetoacetate derivative represented by the general formula: <chemistry id="chem0012" num="0012"><img file="EP0197488A2_D0012.tif" /></chemistry>wherein R⁵ stands for a lower alkyl or lower alkoxy lower alkyl group, a group represented by the general formula: <chemistry id="chem0013" num="0013"><img file="EP0197488A2_D0013.tif" /></chemistry>(wherein p stands for a positive number of 1 to 6 and Z stands for a hydrogen or halogen atom or a lower alkoxy group) or a group represented by the general formula: <chemistry id="chem0014" num="0014"><img file="EP0197488A2_D0014.tif" /></chemistry>(wherein q stands for a positive number of 1 to 6 and M stands for a hydrogen or halogen atom or a lower alkoxy group).</li><li>3 An enaminocarboxylate derivative represented by the general formula: <chemistry id="chem0015" num="0015"><img file="EP0197488A2_D0015.tif" /></chemistry>wherein R' stands for a hydrogen atom or a 4-p-(fluorobenzoyl)-1-piperidyl group; R²stands for a lower alkoxy group, a group represented by the general formula: <chemistry id="chem0016" num="0016"><img file="EP0197488A2_D0016.tif" /></chemistry>(wherein n stands for a positive number of 2 to 6 and W stands for a hydrogen or halogen atom or a lower alkoxy group) or a group represented by the formula: <chemistry id="chem0017" num="0017"><img file="EP0197488A2_D0017.tif" /></chemistry>(wherein R⁶ stands for a hydrogen atom or a nitro group and X stands for a hydrogen or halogen atom or a lower alkoxy group); altematively, R² and R' may together form a ring.</li></ul>

0012The above three components are reacted in the presence of an alcohol preferably selected from among methanol, ethanol, n-propanol, isopropanol, butanol and the like, preferably at a temperature of 50 to 150°C.

0013The amounts of the components 1 and 3 to be used in the reaction are preferably each 1.0 to 2.0 mol per mol of the component 2.

0014An acetoacetate derivative represented by the general formula (III) to be used as a starting material in the above reaction can be prepared by, for example, the following method.

0015An alcohol derivative represented by the general formula: <chemistry id="chem0018" num="0018"><img file="EP0197488A2_D0018.tif" /></chemistry>wherein R⁵ is as defined above is reacted with a diketene in the presence or absence of a solvent to obtain an objective acetoacetate derivative. Preferred examples of the solvent include benzene, toluene and xylene. It is preferred that an alcohol derivative (V) is reacted with a diketene in a molar ratio of between 1 : 1 and 1 : 3. The reaction temperature is preferably 0 to 150°C.

0016Preparation method B [for compounds represented by the formula (I) wherein R⁴ is H] <chemistry id="chem0019" num="0019"><img file="EP0197488A2_D0019.tif" /></chemistry>wherein R' and R^S are as defined above <chemistry id="chem0020" num="0020"><img file="EP0197488A2_D0020.tif" /></chemistry>wherein R² and R³ are as defined above <chemistry id="chem0021" num="0021"><img file="EP0197488A2_D0021.tif" /></chemistry>That is to say, a benzylideneacetoacetate derivative represented by the general formula (VI) is reacted with an enaminocarboxylate derivative (IV) to obtain an objective compound (I).

0017This reaction is carried out generally at a temperature of 50 to 150°C in the presence of an alcohol solvent such as methanol, ethanol, n-butanol, isopropanol or butanol. It is preferred that a benzylideneacetoacetate derivative (VI) is reacted with an enaminocarboxylate derivative (IV) in a molar ratio of between 1 : 1 and 1 : 2.

0018A benzylideneacetoacetate derivative (VI) to be used as a starting material in this method can be prepared by reacting a compound represented by the general formula (II) with a compound represented by the general formula (III) according to known methods, for example, a method described in Organic Synthesis, Collective Vol. 4, p.408 - (1963).

Preparation Method C

0019(for compounds represented by the general formula (I) wherein R⁴ stands for a hydrogen atom, a lower alkyl or phenylalkyl group or a group represented by the formula -CH₂-L [wherein L stands for a group of -OR⁷resented by (wherein R⁷ stands for a lower alkyl group) or a group represented by the general formula: <chemistry id="chem0022" num="0022"><img file="EP0197488A2_D0022.tif" /></chemistry>(wherein m stands for a positive number of 0 to 5 and Y stands for a hydrogen or halogen atom or a lower alkoxy group)}.

0020The following three components are condensed to obtain an objective compound. <ul id="ul0005" list-style="none"><li>1 A compound represented by the general formula: <chemistry id="chem0023" num="0023"><img file="EP0197488A2_D0023.tif" /></chemistry>wherein R' and R⁵ are as defined above.</li><li>2 A compound represented by the general formula: <chemistry id="chem0024" num="0024"><img file="EP0197488A2_D0024.tif" /></chemistry>wherein R⁵ is as defined above or <chemistry id="chem0025" num="0025"><img file="EP0197488A2_D0025.tif" /></chemistry>wherein r stands for a positive number of 2 to 4.</li><li>3 An aqueous ammonia (VIII) or a compound represented by the general formula: <chemistry id="chem0026" num="0026"><img file="EP0197488A2_D0026.tif" /></chemistry>wherein s stands for a positive number of 0 to 6 and R⁹ stands for a hydrogen atom or a lower alkyl, phenylalkyl, lower alkoxy or phenyl group, a group represented by the formula <chemistry id="chem0027" num="0027"><img file="EP0197488A2_D0027.tif" /></chemistry>(wherein R'° and R" may be the same or different from each other and each stands for a lower alkyl group) or a group represented by the formula <chemistry id="chem0028" num="0028"><img file="EP0197488A2_D0028.tif" /></chemistry>(wherein Y stands for a hydrogen or halogen atom or a lower alkoxy group).</li></ul>

0021The above condensation of components 1, 2 and 3 is carried out in the presence of a solvent at a temperature of 50 to 150°C to obtain an objective compound. It is preferred to use about 1.0 to 2.0 mol of component 2 and about 1.0 to 10 mol of component 3 per mol of component 1 in the condensation. The solvent is preferably selected from among alcohols and particular examples thereof include methanol, ethanol, n-butanol, isopropanol and butanol.

0022Now, representative compounds of the present invention will be described to give a better understanding of the present invention. Of course, these representative compounds do not restrict the present invention, but are for the above purpose. <ul id="ul0006" list-style="none"><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl isopropyl 2,6-dimethyl-4-(o,m-dichlorophenyl)-1,4- dihyrdropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl propyl 2,6-dimethyl-4-(o,m-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>* 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methoxyethyl 2,6-dimethyl-4-(o,m-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-chiorobenzoyl)-1-piperidyl]ethyl benzyl 2,6-dimethyl-4-(o,m-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(benzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-chlorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,4-dicarboxylate</li><li>• 2-[4-(p-bromobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-methoxybenzoyl)-l-piperidyl]ethyl methyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-piperidyl]ethyl methyl 1-ethyl-2,6-dimethyl-4-(o-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 1-benzyl-2,6-dimethyl-4-(o-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl ethoxymethyl 1-benzyl-2,6-dimethyl-4-(o-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 1- {2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl}-2,6-dimethyl-4-(o-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 4-(m-nitrophenyl)-3-ethoxycarbonyl-5-methoxycarbonyl-6-methyl-2-[4-(p-fluorobenzoyl)-1-piperidyl]-ethoxymethyl-1,4-dihydropyridine</li><li>• 2-[4-(p-fluarobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(2',3'-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyly-1-piperidyl]ethyl ethyl 2,6-dimethyl-4-(2',3'-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl 2-methoxyethyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(o-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl ethyl 2,6-dimethyl-4-(o-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl ethyl 2,6-dimethyl-4-(o-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(m-trifluoromethylphenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 3-[4-(p-fluorobenzoyl)-1-piperidyl]proxyl methyl 2,6-dimethyl-4-(o-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>. 6-[4-(p-fluorobenzoyl)-1-piperidyl]hexyl methyl 2,6-dimethyl-4-(o-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(hydroxy-p-fluorophenylmethyl)-1-piperidyl]-ethyl methyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(nitroxy-p-fluorophenylmethyl)1-piperidyl]-ethyl methyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(m,p-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(o-chlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(o-bromophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(p-chlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(o,p-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(2'-chloro-5'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(2',6'-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(m-chlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>* 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(o-cyanophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-naphthyl-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(3-pyridyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(2'-chloro-4',5'-methylenedioxyphenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>. 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(m-nitro-p-chlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>. 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(2-furyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>. 2-[4-(p-fluorobenzoyl)-l-piperidyl]ethyl methyl 2,6-dimethyl-4-(3-indolyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(hydroxy-p-fluorophenylmethyl)-1-piperidyl]-ethyl ethyl 2,6-dimethyl-4-(m-chlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-methyl-3-methoxycarbonyl-4-(m-nitrophenyl)-5- ethoxycarbonyl-6-[4-(p-fluorobenzoyl)-1-piperidyl]-methyl-1,4-dihydropyridine</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl ethyl 2,6-dimethyl-4-(2',3'-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[-4-(p-fluorobenzoyl)-1-piperidyl]ethyl ethyl 2,6-dimethyl-4-(o-chlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-methyl-4-(o-fluorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl 2-[4-p-fluorobenzoyl)-1-piperidyl]ethyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate</li><li>• 2-methyl-3-[2-(4-p-fluorobenzoyl)-1-piperidyl]-ethoxycarbonyl-4-(m-nitrophenyl)-5(1 H, 4H, 6H, 7H, 8H)-pentahydroquinolinone</li><li>• 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl 2-methoxyethyl 2,6-dimethyl-4-(m-nitrophenyl)-3,5-dicarboxylate</li></ul>

0023The 1,4-dihydropyridine derivatives of the present invention exhibits excellent hypotensive and coronary vasodilating actions.

0024Up to this time, some 1,4-dihydropyridine derivatives have been used as a medicine for treatment of cardiopathy, brain circulation failure or hypertension. Representatively, nifedipin[4-(2'-nitrophenyl)-2,6-dimethyl-3,5-dicarbomethoxy-1,4-dihydropyridine] and nicaldipinimethyl 2-[methyl-(phenylmethyl)amino]ethyl 1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5-pyridinedicarboxylate} are known as such a medicine. However, these compounds exhibit a relatively short duration of action, thus being significantly problematic in persistency. A medicine for circulatory disease must generally be used repeatedly for a long time owing to characteristics of this disease, so that the development of a medicine for treatment of hypertension or cardiopathy exhibiting a persistent and stable action has been desired.

0025The inventors of the present invention have long studied on 1,4-dihydropyridine derivative free from the above disadvantage and have found that a 1,4-dihydropyridine derivative represented by the formula (1) is free from the disadvantage and is very useful as a medicine for treatment of cardiopathy, brain circulation failure, hypertension or the like. The present invention has been accomplished on the basis of this finding.

0026The present invention relates to a 1,4-dihydropyridine derivative represented by the general formula: <chemistry id="chem0029" num="0029"><img file="EP0197488A2_D0029.tif" /></chemistry>wherein R' stands for an aryl or heteroaryl group which may be substituted with a lower alkyl, lower alkoxy, halogen, nitro, trofluoromethyl or cyano group or may form an alkylenedioxy group together with an adjacent carbon atom constituting an aryl group; R² stands for a lower alkoxy group, a group represented by the general formula: <chemistry id="chem0030" num="0030"><img file="EP0197488A2_D0030.tif" /></chemistry>(wherein n stands for a positive number of 2 to.6 and W stands for a hydrogen or halogen atom or a lower alkoxy group) or a group represented by the general formula: <chemistry id="chem0031" num="0031"><img file="EP0197488A2_D0031.tif" /></chemistry> (wherein R⁶ stands for. a hydrogen atom or a nitro group and X stands for a hydrogen or halogen atom or a lower alkoxy group); <ul id="ul0007" list-style="none"><li>R³ stands for a hydrogen atom or a 4-p-(fluorobenzoyl)-1-piperidyl group, or alternatively, R² and R' may together form a ring;</li><li>R⁴ stands for a hydrogen atom, a lower alkyl or phenylalkyl group or a group represented by the formula -CH₂-L [wherein L stands for a group of - OR (wherein R' stands for a lower alkyl group) or a group represented by the general formula: <chemistry id="chem0032" num="0032"><img file="EP0197488A2_D0032.tif" /></chemistry>(wherein m stands for a positive number of 0 to 5 and Y stands for a hydrogen or halogen atom or a lower alkoxy group);</li><li>R⁵ stands for a lower alkyl or lower alkoxy lower alkyl group, a group represented by the general formula: <chemistry id="chem0033" num="0033"><img file="EP0197488A2_D0033.tif" /></chemistry>(wherein p stands for a positive number of 1 to 6 and Z stands for a hydorgen or halogen atom or a lower alkoxy group) or a group represented by the general formula: <chemistry id="chem0034" num="0034"><img file="EP0197488A2_D0034.tif" /></chemistry>(wherein q stands for a positive number of 1 to 6 and M stands for a hydrogen or halogen atom or a lower alkoxy group),</li></ul> or its pharmaceutically acceptable salt.

0027The compound (I) of the present invention is characterized by exhibiting not only persistent hypotensive and coronary vasodilating actions based on calcium antagonism but also remarkable serotonin-blocking (5-HT2) and α,-blocking action which no 1,4-dihydropyridine derivatives of the prior art can exhibit.

0028The compound of the present invention is useful as a medicine for treatment or prevention of cardiopathy with an enhanced thrombotic power such as hypertension, angina pectori or myocardial infarction.

0029That is to say, an object of the present invention is to provide a novel 1,4-dihydropyridine derivative which exhibits persistent coronary vasodilating and hypotensive actions and is useful as a medicine based on these actions, a process for the preparation thereof and a medicine containing it as an active principle.

0030Now, Experimental Examples will be given to illustrate the effects of the compound of the present invention in more detail.

Experimental Example 1

Antihypertensive action

(1) Experimental procedure

0031A spontaneously hypertensive male rat (SHR) in a non-narcotized state was examined for systolic pressure at a tail artery with a sphygmomanometer (KN-209 type made by Natsume Works).

0032Each test compound was suspended on 0.5% solution of methylcellulose and adminstered per os with a gastrosonde.

0033Nifedipin and nicaldipin were used as a control.

(2) Test compounds

0034<ul id="ul0008" list-style="none"><li>Compound A: 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl ethyl 2,6-dimethyl-4-(o-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate hydrochloride</li><li>Compound B: 2-[-4(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate hydrochloride</li><li>Compound C: 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl ethyl 2,6-dimethyl-4-{o,m-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate hydrochloride</li><li>Compound D: 2-[4-(p-fluorobenzayl)-1-piperidyl]ethyl ethyl 2,6-dimethyl-4-(o-chlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate hydrochloride</li></ul>

(3) Results

0035The obtained results are shown in Table 1. Table 1 shows the maximum degree of blood pressure drop after the oral administration of 10 mg/kg of a test compound (AmmHg), duration of action and changes in heart rate (A heart rate/min). <tables id="tabl0001" num="0001"><img file="EP0197488A2_D0035.tif" /></tables>

Experimental Examination 2

Coronary vasodilating action and action on blood pressure or heart rate

(1) Experimental procedure

0036Mongrel dogs (male and female) were narcotized with pentobarbital sodium and examined for blood pressure at a femoral artery with a pressure transducer (MPU-0.5A made by Nippon Koden) and for heart rate with a heart rate tachometer. Further, the flow rate of coronary blood was determined with an electromagnetic blood-flow meter - (MFV-1100 made by Nippon Koden) whose probe was jointed to a left-lotating plate. The recording was carried out with a pen oscillograph. Each test compound was dissolved in a 50% solution of polyethylene glycol and injected intravenously.

(2) Results

0037The obtained results are shown in Table 2, wherein the coronary vasodilating action is shown in terms of ratio (percentage) of flow rate for 15 minutes after the intravenous administration of 10 u.g/kg of a test compound to that before the administration. <tables id="tabl0002" num="0002"><img file="EP0197488A2_D0036.tif" /></tables>

0038It is clear from the above results that the compound of the present invention exhibits hypotensive and coronary vasodilating actions. Accordingly, it is useful as a medicine for treatment or prevention of hypertension, brain circulation failure, and cardiopathy such as ischemic heart disease (for example, angina pectori or myocardial infarction).

0039Particularly, the compound of the present invention is characterized by exhibiting a long duration of action, thus being very valuable in this point.

0040The dose of the compound of the present invention to be administered to a patient of such a disease is varied depending upon kind or degree of disease, kind of a compound or age of a patient, though not particularly limited. Generally, the compound of the present invention is administered with a dose of about 1 to 1000 mg, preferably about 5 to 300 mg, more preferably 5 to 60 mg per adult and a day orally or parenterally. The dose is preferably administered in 2 to 4 instalments a day. The administration form may be powder, fine granule, granule, tablet, capsule, injection or the like.

0041The compound of the present invention exhibits a remarkably low toxicity, thus being very safe.

0042The compound of the present invention can be converted into a medicine by using an ordinary carrier according to an ordinary method.

0043For example, a solid medicine for oral administration can be prepared by mixing a principal agent with a filler and, if necessary, a binder, a disintegrating agent, a lubricant, a coloring agent, a corrigent or the like and converting the obtained mixture into tablet, coated tablet, granule, powder, capsule or the like according to an ordinary method.

0044Examples of the filler include lactose, corn starch, sucrose, glucose, sorbitol, crystalline cellulose and silicon dioxide, while those of the binder include polyvinyl alcohol, polyvinyl ether, ethylcellulose, methylcellulose, acacia, tragacanth, gelatin, shellac, hydroxypropylcellulose, hydroxypropyl- starch and polyvinylpyrrolidohe. Examples of the disintegrating agent include starch, agar, gelatin powder, crystalline cellulose, calcium carbide, sodium hydrogen carbonate, calcium citrate, dextrin and pectin. Examples of the lubricant include magnesium stearate, talc, polyethylene glycol, silica and hardened vegetable oil. The coloring agent may be any one which is premitted to be added to drugs. Examples of the corrigent include cocoa powder, menthol, aromatic acid, mentha oil, borneol and cinnamon bark powder. The tablet and glanule may of course be coated with sugar, gelatin or other suitable substances.

0045A medicine for injection can be prepared by, if necessary, mixing a principal agent with pH adjuster, buffer, stabilizer, solubilizing agent or the like and converting the resulting mixture into a medicine for injection according to an ordinary method.

0046The following Formulation Examples 1 and 2 will describe the particular examples of a medicine containing the compound of the present invention, wherein the "active principal" refers to 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl ethyl 2,6-dimethyl-4-(o-filuorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate. <tables id="tabl0003" num="0003"><img file="EP0197488A2_D0037.tif" /></tables>

0047According to an ordinary method, the above components were mixed and converted into a granule. The granule was compression-molded into a tablet having a weight of 100 mg. <tables id="tabl0004" num="0004"><img file="EP0197488A2_D0038.tif" /></tables>

0048A capsule having a weight of 100 mg was prepared by the use of the above formulation according to an ordinary method.

0049Now, Examples of the present invention will be described below, though the present invention is not limited by them.

Example 1

2-[4-(p-Fluorobenzoyl-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate hydrochloride

00508.3 g of m-nitrobenzaldehyde, 2.9 g of methyl 3-aminocrotonate, 3.8 g of 2-[4-(p-fluorobenzyl)-1-piperidyl]ethyl acetoacetate and 100 ml of isopropanol were mixed and heated under reflux for 5 hours.

0051The reaction mixture was concentrated under a reduced pressure. The residue was purified by silica gel chromatograph (with an eluent consisting of chloroform and ethanol in a ratio by volume of 20 to 1) to obtain a viscous oil. The oil was dissolved in 100 ml of chloroform. The resulting solution was washed with 50 ml of 1 N hydrochloric acid and concentrated under a reduced pressure. The residue was crystallized from ethyl acetate to obtain 11.4 g of the title compound.

0052<tables id="tabl0005" num="0005"><img file="EP0197488A2_D0039.tif" /></tables>

Example 2

2-[4-(p-Fluorobenzoyl)-l-piperidyl]ethyl methyl 2,6-dimethyl-4-(2',3'-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate hydrochloride

00531.9 g of o,m-dichlorobenzaldehyde, 1,3 g of methyl 3-aminocrotonate, 3.8 g of 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl acetoacetate and 3Q ml of isopropanol were mixed and heated under reflux for 6 hours.

0054The reaction mixture was concentrated under a reduced pressure. The residue was purified by silica gel chromatography (with an eluent consisting of chloroform and ethanol in a ratio by volume of 20 to 1) to obtain a viscous oil. The oil was dissolved in 50 ml of chloroform. The resulting solution was washed with 20 ml of 1 N hydrochloric acid and concentrated under a reduced pressure. The residue was crystallized from ethyl acetate to obtain 1.3 g of the title compound.

0055<tables id="tabl0006" num="0006"><img file="EP0197488A2_D0040.tif" /></tables>

Example 3

2-[4-(p-Fluorobenzoyl)-1-piperidyl]ethyl ethyl 2,6-dimethyl-4-(2',3'-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate hydrochloride

00564.1 g of 2-[4-(p-fluorobenzoyl)-l-piperidyl]ethyl 2-(o,m-dichlorobenzylidene)acetoacetate, 1.3 g of ethyl 3-aminocrotonate and 30 ml of isopropanol were mixed and heated under reflux for 5 hours.

0057The reaction mixture was concentrated under a reduced pressure. The residue was purified by silica gel chromatography (with an eluent consisting of chloroform and ethanol in a ratio by volume of 20 to 1) to obtain a viscous oil.

0058The oil was dissolved in 50 .ml of chloroform. The resulting solution was washed with 20 ml of 1 N hydrochloric acid and concentrated under a reduced pressure.

0059The residue was crystallized from ethyl acetate to obtain 1.7 g of the title compound. <tables id="tabl0007" num="0007"><img file="EP0197488A2_D0041.tif" /></tables>

Example 4

2-[4-(p-Fluorobenzoyl)-1-piperidyl]ethyl ethyl 2,6-dimethyl-4-(o-chlorophenyl)-1,4-dihydropyridine3,5-dicarboxylate hydrochloride

00604.7 g of 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl 2-(o-chlorobenzylidene)acetoacetate, 1.5 g of ethyl 3-aminocrotonate and 30 ml of isopropanol were mixed and heated under reflux for 6 hours.

0061The reaction mixture was concentrated under a reduced pressure. The residue was purified by silica gel chromatography (with an eluent consisting of chloroform and ethanol in a ratio by volume of 20 to 1) to obtain a viscous oil.

0062The oil was dissolved in 50 ml of chloroform. The resulting solution was washed with 20 ml of 1 N hydrochloric acid and concentrated under a reduced pressure.

0063The residue was crystallized from ethyl acetate to obtain 1.5 g of the title compound. <tables id="tabl0008" num="0008"><img file="EP0197488A2_D0042.tif" /></tables>

Example 5

2-[4-(p-Fluorobenzoyl)-1-piperidyl]ethyl 2-methoxyethyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate hydrochloride

00642.0 g of 2-methoxyethyl 2-(m-nitrobenzylidene)-acetoacetate, 2.3 g of 2-[4-(p-fluorobenzoyl)-1-piperidyllethyl acetoacetate, 0.6 g of 28% aqueous ammonia and 30 ml of isopropanol were mixed and heated at 120° C for 12 hours.

0065After the completion of the reaction, the reaction mixture was poured into 50 ml of water and extracted with 50 ml of chloroform. The extract was concentrated under a reduced pressure. The resulting residue was purified by silica gel chromatography (with an eluent consisting of chloroform and ethanol in a ratio by volume of 20 to 1) to obtain a viscous oil.

0066The oil was dissolved in 50 ml of chloroform. The resulting solution was washed with 20 ml of 1N hydrochloric acid and concentrated under a reduced pressure.

0067The residue was crystallized from ethyl acetate to obtain 0.5 g of the title compound. <tables id="tabl0009" num="0009"><img file="EP0197488A2_D0043.tif" /></tables>

Referential Example

0068The 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl acetoacetate used in Example 1 as a starting material was prepared as follows: <ul id="ul0009" list-style="none"><li>290g of 2-[4-(p-fluorobenzoyl)-1-piperidyl]-ethanol_°was mixed with toluene. The resulting mixture was heated at 45°C. 103 g of diketene was dropwise added to the mixture over 20 minutes. After the completion of the dropwise addition, the resulting mixture was heated at 45°C for 1 hour.</li></ul>

0069After the completion of the reaction, the reaction mixture was washed with 300 ml of water and concentrated under a reduced pressure. The residue was purified by silica gel chromatography (with an eluent consisting of chloroform and ethanol in a ratio by volume of 20 to 1) to obtain 315 g of 2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl acetoacetate as an oil having the following characteristics: <tables id="tabl0010" num="0010"><img file="EP0197488A2_D0044.tif" /></tables>

Examples 6 to 29

0070The following compounds were synthesized according to the same procedure as the one described in Example 1 or 2. The NMR spectrum - (CDCl₃) of each compound (free form) will also be shown below.

Example 6:

2-[4-(p-fiuorobenzoyl)-1-piperidyl]ethyl methyl 2,8-dimethyl-4-(o-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0071<ul id="ul0010" list-style="none"><li>NMR (CDCI₃)</li><li>2.29 (3H, s), 2.35 (3H, s), 2.58 (2H, t),</li><li>3.57 (3H, s), 4.17 (2H, t), 5.80 (1 H, s),</li><li>5.85 (1 H, s), 7.95 (2H, dd)</li></ul>

Example 7:

2-[4-(p-f)uorobenzoyl)-1-piperidyl]ethyl ethyl 2,6-dimethyl-4-(o-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0072<ul id="ul0011" list-style="none"><li>NMR (CDCl₃)</li><li>2.30 (3H, s), 2.32 (3H, s), 2.58 (2H, t), 5.73</li><li>(1 H, s), 5.80 (1 H, s), 7.95 (2H, dd), 1.17 (3H, t)</li></ul>

Example 8:

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(m-trifluoromethylphenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0073<ul id="ul0012" list-style="none"><li>NMR (CDCI,)</li><li>2.30 (3H, s), 2.38 (3H, s), 2.48 (2H, t),</li><li>3.62 (3H, s), 4.17 (2H, t), 6.29 (1 H, s),</li><li>5.06 (1H, s), 7.95 (2H, dd)</li></ul>

Example 9:

3-[4-(p-fluorobenzoyl)-l-piperidyl]propyl methyl 2,6-dimethyl-4-(o-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0074<ul id="ul0013" list-style="none"><li>NMR (CDCl₃)</li><li>2.32 (3H, s), 2.38 (3H, s), 2.52 (2H, t)</li><li>3.57 (3H, 2), 6.17 (1 H, s), 5.75 (1 H, s),</li><li>7.94 (2H, dd)</li></ul>

Example 10:

6-[4-(p-fluorobenzoyl)-1-piperidyl]hexyl methyl 2,6-dimethyl-4-(o-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0075<ul id="ul0014" list-style="none"><li>NMR (CDCl₃)</li><li>2.28 (3H, s), 2.35 (3H, s), 2.61 (2H, t),</li><li>3.50 (3H, s), 3.98 (2H, t), 6.20 (1 H, s),</li><li>5.70 (1 H, s), 7.90 (2H, dd)</li></ul>

Example 11:

2-[4-(hydroxy-p-fluorophenylmethyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0076<ul id="ul0015" list-style="none"><li>NMR (CDCl₃)</li><li>2.32 (6H, s), 2.50 (2H, t), 3.60 (3H, s),</li><li>4.10 (2H, t), 5.75 (1 H, s), 5.20 (1 H, s),</li><li>4,31 (1 H, d) .</li></ul>

Example 12:

2-[4-(nitroyx-p-fluorophenylmethyl)-1-piperidyl]-ethyl methyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0077<ul id="ul0016" list-style="none"><li>NMR (CDCl₃)</li><li>2.30 (3H, s), 2.36 (3H, s), 2.47 (2H, t),</li><li>3.57 (3H, s), 4.06 (2H, t), 5.75 (1 H, s),</li><li>5.23 (1 H, s), 4.26 (1 H, d)</li></ul>

Example 13:

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(m,p-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0078<ul id="ul0017" list-style="none"><li>NMR (CDCl₃)</li><li>2.31 (6H, s), 2.50 (2H, t), 3.54 (3H, s),</li><li>4.07 (4H, t), 5.95 (1 H, s), 5.23 (1 H, s),</li><li>7.92 (2H, dd)</li></ul>

Example 14:

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(o-chlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0079<ul id="ul0018" list-style="none"><li>NMR (CDCl₃)</li><li>2.33 (3H, s), 2.58 (3H, s), 2.50 (2H, t),</li><li>3.58 (3H, s), 4.05 (2H, t), 5.40 (1 H, s),</li><li>5.28 (1 H, s), 7.96 (2H, dd)</li></ul>

Example 15

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(o-bromophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0080<ul id="ul0019" list-style="none"><li>NMR (CDCl₃</li><li>2.32 (3H, s), 2.35 (3H, s), 2.60 (2H, t),</li><li>3.62 (3H, 2), 4.20 (2H, t), 5.57 (1 H, s),</li><li>5.35 (1 H, s), 7.96 (2H, dd)</li></ul>

Example 16:

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(p-chlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0081<ul id="ul0020" list-style="none"><li>NMR (CDCl₃)</li><li>2.30 (3H, s), 2.34 (3H, s), 2.58 (2H, t),</li><li>3.62 (3H, s), 4.17 (2H, t), 5.77 (1 H, s),</li><li>4.97 (1 H, s), 7.95 (2H, dd) _</li></ul>

Example 17:

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(o,p-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0082<ul id="ul0021" list-style="none"><li>NMR (CDCl₃)</li><li>2.30 (6H, s), 2.58 (2H, t), 3.60 (3H, s),</li><li>4.13 (2H, t), 5.62 (1 H, s), 5.32 (1 H, s),</li><li>7.96 (2H, dd) -</li></ul>

Example 18

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl -4-(2'-chloro-5'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0083<ul id="ul0022" list-style="none"><li>NMR (CDCl₃)</li><li>2.40 (6H, s), 2.65 (2H, t), 3.67 (3H, s),</li><li>4.23 (2H, t), 6.70 (1 H, s), 5.52 (1 H, s),</li><li>7.94 (2H, dd)</li></ul>

Example 19:

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(2', 6'-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0084<ul id="ul0023" list-style="none"><li>NMR (CDCl₃)</li><li>2.10 (6H, s), 2.52 (2H, t), 3.52 (3H, s),</li><li>4.12 (2H, t), 6.31 (1 H, s), 5.91 (1 H, s),</li><li>7.96 (2H, dd)</li></ul>

Example 20:

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(m-chforophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0085<ul id="ul0024" list-style="none"><li>NMR (CDCl₃)</li><li>2.34 (3H, s), 2.36 (3H, s), 2.61 (2H, t),</li><li>3.65 (3H, s), 4.21 (2H, t), 5.77 (1 H, s),</li><li>5.00 (1H, s), 7.97 (2H, dd)</li></ul>

Example 21:

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(o-cyanophenyl)-1,4-dihydropyridine-3,4-dicarboxylate

0086<ul id="ul0025" list-style="none"><li>NMR (CDCl₃)</li><li>₂.₃₇ (3H, s), 2.39 (3H, s), 2.6₄ (2H, t),</li><li>3.65 (3H, s), 421 (2H, t), 6.76 (1 H, s),</li><li>5.34 (1 H, s), 7.98 (2H, dd)</li></ul>

Example 22:

2-[4-(p-fluorabenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-naphthyl-1,4-dihydropyridine-3,5-dicarboxylate

0087<ul id="ul0026" list-style="none"><li>NMR (CDCl₃)</li><li>227 (3H, s), 2.34 (3H, s), 2.67 (2H, t),</li><li>3.44 (3H, s), 4.03 (2H, t), 6.62 (1 H, s),</li><li>5.83 (1 H, s), 7.95 (2H, dd)</li></ul>

Example 23:

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(3-pyridyl)-1,4-dihydropyridine-3,5-dicarboxylate

0088<ul id="ul0027" list-style="none"><li>NMR (CDCl₃)</li><li>2.36 (3H, s), 2.39 (3H, s), 2.62 (2H, t),</li><li>3.64 (3H, s), 4.19 (2H, t), 6.72 (1 H, s),</li><li>5.04 (1 H, s), 7.98 (2H, dd)</li></ul>

Example 24:

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(2'-chloro-4',5'-methylenedioxyphenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0089<ul id="ul0028" list-style="none"><li>NMR (CDCl₃)</li><li>2.29 (6H, s), 2.68 (2H, t), 3.64 (3H, s),</li><li>4,30 (2H, t), 6.45 (1 H, s), 5.89 (1 H, s),</li><li>7.99 (2H, dd)</li></ul>

Example 25:

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(m-nitro-p-chlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0090<ul id="ul0029" list-style="none"><li>NMR (CDCl₃)</li><li>2.36 (3H, s), 2.38 (3H, s), 2.60 (2H, t),</li><li>3.66 (3H, s), 4.19 (2H, t), 5.95 (1 H, s),</li><li>5.03 (1 H, s), 7.98 (2H, dd) .</li></ul>

Example 26:

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(2-furyl)-1,4-dihydropyridine-3,5-dicarboxylate

0091<ul id="ul0030" list-style="none"><li>NMR (CDCl₃)</li><li>2.25 (6H, s), 2.67 (2H, t), 3.66 (3H, s),</li><li>4.30 (2H, t), 6.00 (1 H, s), 5.05 (1 H, s),</li><li>7.96 (2H, dd)</li></ul>

Example 27:

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(3-indolyl)-1,4-dihydropyridine-3,5-dicarboxylate

0092<ul id="ul0031" list-style="none"><li>NMR (CDCl₃)</li><li>2.30 (3H, s), 2.34 (3H, s), 2.57 (2H, t),</li><li>3.61 (3H, s), 4.14 (2H, t), 6.12 (1 H, s),</li><li>5.34 (1 H, s), 7.92 (2H, dd)</li></ul>

Example 28:

2-[4-(hydroxy-p-fluorophenylmethyl)-1-piperidyl]ethyl ethyl 2,6-dimethyl-4-(m-chlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0093<ul id="ul0032" list-style="none"><li>NMR (CDCI,)</li><li>2.30 (6H, s), 2.54 (2H, t), 5.78 (1 H, s),</li><li>5.36 (1 H, s), 4.33 (1 H, d), 1.19 (3H, t)</li></ul>

Example 29

2-methyl-3-methoxycarbonyl-4-(m-nitrophenyl)-5-ethoxycarbonyl-6-[4-(p-fluorobenzoyl)-1-piperidyl]methyl-1,4-dihydropyridine

0094<ul id="ul0033" list-style="none"><li>NMR (CDCI,)</li><li>2.29 (3H, s), 2.35 (3H, s), 2.58 (2H, t),</li><li>4.17 (2H, t), 5.81 (1 H, s), 5.85 (1 H, s),</li><li>7.95 (2H, dd)</li></ul>

Examples 30 to 32

0095The following compounds were synthesized according to the same procedure as the one described in Example 3 or 4. The NMR spectrum of each compound (CDCl₃) will also be shown below.

Example 30:

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl ethyl 2,6-dimethyl-4-(2',3'-dichlorophenyl)-1,4-dihydro pyridine-3,5-dicarboxylate

0096<ul id="ul0034" list-style="none"><li>NMR (CDCl₃)</li><li>2.29 (3H, s), 2.31 (3H, s), 2.58 (2H, t),</li><li>5.92 (1 H, s), 5.47 (1 H, s), 7.98 (2H, dd)</li><li>1.18 (3H, t)</li></ul>

Example 31:

2-[4-(p-ftuorobenzoyl)-1-piperidyl]ethyl ethyl 2,6-dimethyl-4-(o-chlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0097<ul id="ul0035" list-style="none"><li>NMR (CDCl₃)</li><li>2.33 (6H, s), 2.62 (2H, t), 5.82 (1 H, s),</li><li>5.40 (1 H, s), 7.96 (2H, dd), 1.20 (3H, t)</li></ul>

Example 32:

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl methyl 2,6-dimethyl-4-(o-fluorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0098<ul id="ul0036" list-style="none"><li>NMR (CDCl₃)</li><li>2.30 (3H, s), 2.32 (3H, s), 3.66 (3H, s),</li><li>4.30 (2H, t), 5.45 (1 H, t), 5.89 (1 H, s),</li><li>7.96 (2H, dd)</li></ul>

Examples 33 to 35

0099The following compounds were synthesized according to the same procedure as the one described in Example 5. The NMR spectrum of each compound (CDCl₃) will also be shown below.

Example 33:

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl 2-[4-(p-fluorobenzoyl)-1-piperidyllethyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

0100<ul id="ul0037" list-style="none"><li>NMR (CDCl₃)</li><li>2.38 (6H, s), 2.58 (4H, t), 4.18 (4H, t),</li><li>6.30 (1 H, s), 5.07 (1 H, s), 7.8 -8.1 (4H, m),</li></ul>

Example 34:

2-methyl-3-[2-(4-p-fluorobenzoyl)-1-piperidylethoxycarbonyl-4-(m-nitrophenyl)-5(1H, 4H, 6H, 7H, 8H)-pentahydroquinolinone

0101<ul id="ul0038" list-style="none"><li>NMR (CDCI,)</li><li>3.39 (3H, s), 9.56 (1 H, s), 5.02 (1 H, s),</li><li>7.99 (2H, dd)</li></ul>

Example 35

2-[4-(p-fluorobenzoyl)-1-piperidyl]ethyl 2-methoxyethyl 2,6-dimethyl-4-(m-nitrophenyl-3,5-dicarboxylate

0102<ul id="ul0039" list-style="none"><li>NMR (CDCl₃)</li><li>2.37 (3H, s), 2.39 (3H, s), 2.61 (2H, t),</li><li>6.03 (1 H, s), 5.14 (1 H, s), 7.99 (2H, dd),</li><li>3.36 (1 H, s)</li></ul>

0103Claims <ul id="ul0040" list-style="none"><li>1. A 1,4-dihydropyridine derivative represented by the general formula: <chemistry id="chem0035" num="0035"><img file="EP0197488A2_D0045.tif" /></chemistry> wherein R' stands for an. aryl or heteroaryl group which may be substituted with a lower alkyl, lower alkoxy, halogen, nitro, trifluoromethyl or cyano group or may form an alkylenedioxy group together with an adjacent carbon atom consisting an aryl group; R² stands for a lower alkoxy group, a group represented by the general formula: <chemistry id="chem0036" num="0036"><img file="EP0197488A2_D0046.tif" /></chemistry>(wherein n stands for a positive number of 2 to 6 and W stands for a hydrogen or halogen atom or a lower alkoxy group) or a group represented by the general formula: <chemistry id="chem0037" num="0037"><img file="EP0197488A2_D0047.tif" /></chemistry>(wherein R⁶ stands for a hydrogen atom or a nitro group and X stands for a hydrogen or halogen atom or a lower alkoxy group); <ul id="ul0041" list-style="none"><li>R³ stands for a hydrogen atom or a 4-p-(fluorobenzoyl)-1-piperidyl group, or alternatively, R² and R³ may together form a ring;</li><li>R⁴ stands for a hydrogen atom, a lower alkyl or phenylalkyl group or a group represented by the . formula -CH₂-L [wherein L stands for a group of - OR⁷ (wherein R' stands for a lower alkyl group) or a group represented by the general formula: <chemistry id="chem0038" num="0038"><img file="EP0197488A2_D0048.tif" /></chemistry>(wherein m stands for a positive number of 0 to 5 and Y stands for a hydrogen or halogen atom or a lower alkoxy group)];</li><li>R⁵ stands for a lower alkyl or lower alkoxy-lower alkyl group, a group represented by the general formula: <chemistry id="chem0039" num="0039"><img file="EP0197488A2_D0049.tif" /></chemistry>(wherein p stands for a positive number of 1 to 6 and Z stands for a hydrogen or halogen atom or a lower alkoxy group) or a group represented by the general formula: <chemistry id="chem0040" num="0040"><img file="EP0197488A2_D0050.tif" /></chemistry>(wherein q stands for a positive number of 1 to 6 and M stands for a hydrogen or halogen atom or a lower alkoxy group),</li></ul> or a pharmaceutically acceptable salt thereof.</li><li>2. A process for the preparation of 1,4-dihydropyridine derivative represented by the general formula <chemistry id="chem0041" num="0041"><img file="EP0197488A2_D0051.tif" /></chemistry> wherein R' stands for an aryl or heteroaryl group which may be substituted with a lower alkyl, lower alkoxy, halogen, nitro, trifluoromethyl or cyano group or may form an alkylenedioxy group together with an adjacent carbon atom constituting an aryl group; R² stands for a lower alkoxy group, a group represented by the general formula: <chemistry id="chem0042" num="0042"><img file="EP0197488A2_D0052.tif" /></chemistry>(wherein n stands for a positive number of 2 to 6 and W stands or a hydrogen or halogen atom or a lower alkoxy group) or a group represented by the general formula: <chemistry id="chem0043" num="0043"><img file="EP0197488A2_D0053.tif" /></chemistry>(wherein R⁶ stands for a hydrogen atom or a nitro group and X stnads for a hydrogen or halogen atom or a lower alkoxy group); <ul id="ul0042" list-style="none"><li>R³ stands for a hydrogen atom or a 4-p-(fluorobenzoyl)-1-piperidyl group, or altematively,</li><li>R² and R³ may together form a ring;</li><li>R⁵ stands for a lower alkyl or lower alkoxy lower alkyl group, a group represented by the general formula: <chemistry id="chem0044" num="0044"><img file="EP0197488A2_D0054.tif" /></chemistry>(wherein p stands for a positive number of 1 to 6 and Z stands for a hydrogen or halogen atom or a lower alkoxy group) or a group represented by the general formula: <chemistry id="chem0045" num="0045"><img file="EP0197488A2_D0055.tif" /></chemistry>(wherein q stands for a positive number of 1 to 6 and M stands for a hydorgen or halogen atom or a lower alkoxy group),</li></ul> which comprises reacting</li><li>1 a compound represented by the general formula: <chemistry id="chem0046" num="0046"><img file="EP0197488A2_D0056.tif" /></chemistry>wherein R' is as defined above, with</li><li>2 an acetoacetate derivative represented by the general formula: <chemistry id="chem0047" num="0047"><img file="EP0197488A2_D0057.tif" /></chemistry>wherein R⁵ is as defined above, and</li><li>3 an enaminocarboxylate derivative represent- ed by the general formula: <chemistry id="chem0048" num="0048"><img file="EP0197488A2_D0058.tif" /></chemistry>wherein R² and R' are as defined above.</li><li>3. A process for the preparation of 1,4-dihydropyridine derivative represented by the general formula: <chemistry id="chem0049" num="0049"><img file="EP0197488A2_D0059.tif" /></chemistry>wherein R' stands for an aryl or heteroaryl group which may be substituted with a lower alkyl, lower alkoxy, halogen, nitro, trifluoromethyl or cyano group or may form an alkylenedioxy group together with an adjacent carbon atom consistituting an aryl group; R² stands for a lower alkoxy group, a group represented by the general formula: <chemistry id="chem0050" num="0050"><img file="EP0197488A2_D0060.tif" /></chemistry>(wherein n stands for a positive number of 2 to 6 and W stands for a hydrogen or halogen atom or a lower alkoxy group) or a group represented by the general formula: <chemistry id="chem0051" num="0051"><img file="EP0197488A2_D0061.tif" /></chemistry>(wherein R⁶ stands for a hydrogen atom or a nitro group and X stands for a hydrogen or halogen atom or a lower alkoxy group); R³ stands for a hydrogen atom or a 4-p-(fluorobenzoyl)-1-piperidyl group, or alternatively, R⁷ and R³ may together form a ring; R⁵ stands for a lower alkyl or lower alkoxy lower alkyl group, a group represented by the general formula: <chemistry id="chem0052" num="0052"><img file="EP0197488A2_D0062.tif" /></chemistry>(wherein p stands for a positive number of 1 to 6 and Z stands for a hydrogen or halogen atom or a lower alkoxy group) or a group represented by the general formula: <chemistry id="chem0053" num="0053"><img file="EP0197488A2_D0063.tif" /></chemistry>(wherein q stands for a positive number of 1 to 6 and M stands for a hydorgen or halogen atom or a lower alkoxy group; which comprises reacting a benzylideneacetoacetate derivative represented by the general formula: <chemistry id="chem0054" num="0054"><img file="EP0197488A2_D0064.tif" /></chemistry>wherein R' and R⁵ are as defined above, with an enaminocarboxylate derivative represented by the general formula: <chemistry id="chem0055" num="0055"><img file="EP0197488A2_D0065.tif" /></chemistry>wherein R² and R' are as defined above.</li><li>4. A process for the preparation of a 1,4-dihydropyridine derivative represented by the general formula <chemistry id="chem0056" num="0056"><img file="EP0197488A2_D0066.tif" /></chemistry>wherein R' stands for an aryl or heteroaryl group which may be substituted with a lower alkyl, lower alkoxy, halogen, nitro, trifluoromethyl or cyano group or may form an alkylenedioxy group together with an adjacent carbon atom constituting an aryl group; R² stands for a lower alkoxy group, a group represented by the general formula: <chemistry id="chem0057" num="0057"><img file="EP0197488A2_D0067.tif" /></chemistry>(wherein n stands for a positive number of 2 to 6 and W stands for a hydrogen or halogen atom or a lower alkoxy group) or a group represented by the general formula: <chemistry id="chem0058" num="0058"><img file="EP0197488A2_D0068.tif" /></chemistry>(wherein R⁶ stands for a hydrogen atom or a nitro group and X stands for a hydrogen or halogen atom or a lower alkoxy group); <ul id="ul0043" list-style="none"><li>R³ stands for a hydrogen atom or a 4-p-(fluorobenzoyl)-1-piperidyl group, or alternatively, R² and R' may together form a ring:</li><li>R⁴ stands for a hydrogen atom, a lower alkyl or phenylalkyl group or a group represented by the formula -CH₂-L [wherein L stands for a group of - OR⁷ (wherein R⁷ stands for a lower alkyl group) or a group represented by the general formula: <chemistry id="chem0059" num="0059"><img file="EP0197488A2_D0069.tif" /></chemistry>(wherein m stands for a positive number of 0 to 5 and Y stands for a hydrogen or halogen atom or a lower alkoxy group)];</li><li>R⁵ stands for a lower alkyl or lower alkoxy-lower alkyl group, a group represented by the general formula: <chemistry id="chem0060" num="0060"><img file="EP0197488A2_D0070.tif" /></chemistry>(wherein p stands for a positive number of 1 to 6 and Z stands for a hydrogen or halogen atom or a lower alkoxy group) or a group represented by the general formula: <chemistry id="chem0061" num="0061"><img file="EP0197488A2_D0071.tif" /></chemistry>(wherein q stands for a positive number of 1 to 6 and M stands for a hydrogen or halogen atom or a lower alkoxy group),</li><li>or a pharmaceutically acceptable salt thereof, which comprises condensing a compound represented by the general formula: <chemistry id="chem0062" num="0062"><img file="EP0197488A2_D0072.tif" /></chemistry>wherein R' and R⁵ are as defined above, with a compound represented by the general formula: <chemistry id="chem0063" num="0063"><img file="EP0197488A2_D0073.tif" /></chemistry>wherein R⁵ is as defined above <chemistry id="chem0064" num="0064"><img file="EP0197488A2_D0074.tif" /></chemistry>wherein r stands for a positive number of 2 to 4, and an aqueous ammonia (VIII) or a compound represented by the general formula: <chemistry id="chem0065" num="0065"><img file="EP0197488A2_D0075.tif" /></chemistry>wherein s stands for a positive number of 0 to 6 and R⁹ stands for a hydrogen atom or a lower alkyl, phenylalkyl, lower alkoxy alokoxy or phenyl group, a group represented by the formula <chemistry id="chem0066" num="0066"><img file="EP0197488A2_D0076.tif" /></chemistry> (wherein R'° and R" may be the same or different from each other and each stands for a lower alkyl group) or a group represented by the formula <chemistry id="chem0067" num="0067"><img file="EP0197488A2_D0077.tif" /></chemistry>(wherein Y stands for a hydrogen or halogen atom or a lower alkoxy group).</li></ul></li><li>5. A medicine for treatment or prevention of cardiopathy containing, as an active principle, 1,4-dihydropyridine derivative represented by the general formula: <chemistry id="chem0068" num="0068"><img file="EP0197488A2_D0078.tif" /></chemistry>wherein R' stands for an aryl or heteroaryl group which may be substituted with a lower alkyl, lower alkoxy, halogen, nitro, trofluoromethyl or cyano group or may form an alkylenedioxy group together with an adjacent carbon atom constituting an aryl group; R² stands for a lower alkoxy group, a group represented by the general formula: <chemistry id="chem0069" num="0069"><img file="EP0197488A2_D0079.tif" /></chemistry>(wherein n stands for a positive number of 2 to 6 and W stands for a hydrogen or halogen atom or a lower alkoxy group) or a group represented by the general formula: <chemistry id="chem0070" num="0070"><img file="EP0197488A2_D0080.tif" /></chemistry>(wherein R⁶ stands for a hydrogen atom or a nitro group and X stands for a hydorgen or halogen atom or a lower alkoxy group); <ul id="ul0044" list-style="none"><li>R³ stands for a hydrogen atom or a 4-p-fluorobenzoyl)-1-piperidyl group, or alternatively, R² and R³ may together form a ring;</li><li>R⁴ stands for a hydrogen atom, a lower alkyl or phenylalkyl group or a group represented by the formula -CH2-L [wherein L stands for a group of -OR⁷ (wherein R⁷ stands for a lower alkyl group) or a group represented by the general formula: <chemistry id="chem0071" num="0071"><img file="EP0197488A2_D0081.tif" /></chemistry>(wherein m stands for a positive number of 0 to 5 and Y stands for a hydrogen or halogen atom or a lower alkoxy group);</li><li>R^S stands for a lower alkyl or lower alkoxy lower alkyl group, a group represented by the general formula: <chemistry id="chem0072" num="0072"><img file="EP0197488A2_D0082.tif" /></chemistry>(wherein p stands for a positive number of 1 to 6 and Z stands for a hydrogen or halogen atom or a lower alkoxy group) or a group represented by the géneral formula: <chemistry id="chem0073" num="0073"><img file="EP0197488A2_D0083.tif" /></chemistry>(wherein q stands for a positive number of 1 to 6 and M stands for a hydrogen or halogen atom or a lower alkoxy group),</li></ul> or its pharmaceutically acceptable salt.</li><li>6. A medicine based on antihypertensive or coronary vasodilating action containing, as an active principle, 1,4-dihydropyridine derivative represented by the general formula: <chemistry id="chem0074" num="0074"><img file="EP0197488A2_D0084.tif" /></chemistry>wherein R' stands for an aryl or heteroaryl group which may be substituted with a lower alkyl, lower alkoxy, halogen, nitro, trifluoromethyl or cyano group or may form an alkylene dioxy group together with an adjacent carbon atom constituting an aryl group; R²stands for a lower alkoxy group, a group represented by the general formula: <chemistry id="chem0075" num="0075"><img file="EP0197488A2_D0085.tif" /></chemistry>(wherein n stands for a positive number of 2 to 6 and W stands for a hydrogen or halogen atom or a lower alkoxy group) or a group repressented by the general formula: <chemistry id="chem0076" num="0076"><img file="EP0197488A2_D0086.tif" /></chemistry>(wherein R⁶ stands for a hydrogen atom or a nitro group and X stands for a hydrogen or halogen atom or a lower alkoxy group); <ul id="ul0045" list-style="none"><li>R³ stands for a hydrogen atom or a 4-p-(fluorobenzoyl)-1-piperidyl- group, or alternatively, R² and R³ may together form a ring; .</li><li>R⁴ stands for a hydrogen atom, a lower alkyl or phenylalkyl group or a group represented by the formula -CH₂-L [wherein L stands for a group of - OR⁷ (wherein R⁷ stands for a lower alkyl group) or a group represented by the general formula: <chemistry id="chem0077" num="0077"><img file="EP0197488A2_D0087.tif" /></chemistry>(wherein m stands for a positive number of 0 to 5 and Y stands for a hydrogen or halogen atom or a lower alkoxy group);</li><li>R⁵ stands for a lower alkyl or lower alkoxy lower alkyl group, a group represented by the general formula: <chemistry id="chem0078" num="0078"><img file="EP0197488A2_D0088.tif" /></chemistry>(wherein p stands for a positive number of 1 to 6 and Z stands for a hydrogen or halogen atom or a lower alkoxy group) or a group represented by the general formula: <chemistry id="chem0079" num="0079"><img file="EP0197488A2_D0089.tif" /></chemistry>(wherein q stands for a positive number of 1 to 6 and M stands for a hydrogen or halogen atom or a lower alkoxy group),</li></ul> or its pharmaceutically acceptable salt.</li><li>7. The use of 1,4-dihydropyridine derivative according to claim 1 as well as pharmaceutically acceptable salts thereof for the preparation of a drug for the treatment or prevention of cardiopathy.</li><li>8. The use of 1,4-dihydropyridine derivative according to claim 1 as well as pharmaceutically acceptable salts thereof for the preparation of a drug for the treatment of brain circulation failure or hypertension.</li></ul>