VINYL CARBOXYLIC ACID DERIVATIVES, THEIR PRODUCTION AND USE

Abstract: Novel compound of the formula: [wherein R¹ is a pyridyl group; R² is a phenyl, thienyl, furyl, naphthyl, benzothienyl or pyridyl group which may have as a substituent a lower alkoxy, a lower alkyl, a halogen, tri­ fluoromethyl, a lower alkenyl or methylenedioxy; R³ is hydrogen, benzyl or a lower alkyl; one of R⁴ and R⁵ is hydrogen or a lower alkyl, and the other is an aryloxy, or lower aliphatic hydrocarbon, an alicyclic hydrocarbon having not more than 6 carbon atoms or an aromatic group which may have a substituent, or a group represented by the formula, -S(O) m -T⁶ (in which R⁶ is phenyl or a lower alkyl group; m is an integer of 0 to 2), or R⁴ and R⁵ each combine with the other to represent an alkylene group; n is an integer of 2 to 6], or a pharmaceutically acceptable salt thereof, has a selective inhibitory action on bio-synthesis of thromboxane A₂(TXA₂) and an effect of enhancing the production of prostaglandin I₂(PG₂), and can be used for mammals in the prevention and treatment of arterial thrombosis caused by platelet aggregation or ischemic disease caused by vaso­ spasms in cardiac, cerebral and peripheral circulatory sys­ tems (e.g. cardian infarction, apoplexy, infarct of blood vessels in kidney, lung and other organs, pectic ulcer etc.).

Description: The present invention relates to novel substituted vinylcarboxylic acid derivatives which possess the action of inhibiting specifically the thromboxane A₂ (TXA₂) synthetase. TXA₂ is a metabolite of arachidonic acid and has a platelet aggregating action. Therefore, it has been known that excessive production of TXA₂ in the body causes various ischemic disorders in the heart, kidney and brain due to occlusion or constriction of a blood vessel. The present inventors conducted research on the synthesis of, and investigation into, materials exhibiting an inhibitory action against the TXA₂ synthetase and, as a result, found a group of novel compounds which possess an excellent inhibitory action against the TXA₂ synthetase. GB-A-2068950 describes pyridine thromboxane synthetase inhibitors having the formula: wherein m is 0 or 1; X is 0 or S; Y is either (a) -(CH₂)n - wherein n is 0 or an integer of from 1 to 5 or (b) a 5- or 6-membered heterocyclic group; R' is hydrogen or a C₁-C₄ alkyl group; and R² is a polar group, provided that, when Y is isoxazolyl, R² may also be methyl. GB-A-2039903 discloses that pyridine derivatives of the general formula: [wherein A represents a C₁ - ₅ alkylene group unsubstituted or substituted by a hydroxy group, B represents a single bond, oxygen, sulphur, or a C₁ ⁻ ₅ alkylene group, D represents a single bond, or a C₁ ⁻ ₅ alkylene group, E represents a grouping of the formula: (in which R⁶ represents hydrogen, or C₁ ⁻ ₄ alkyl, Z represents a single bond, -C = C-, (in which R² represents hydrogen C₁ ⁻ ₄ alkyl, R³ represents hydrogen, bromide, chloride or C₁ ⁻ ₄ alkyl, the symbol --- represents a single or double bond, the carbon atom attached to R² binds to B, and the carbon atom attached to R³ binds to D), R¹ represents hydroxy, -C00R⁴ or -C0SR⁴ (in which R⁴ represents hydrogen, C₁ ⁻ ₁₂ alkyl, C₇ ⁻ ₁₃ aralkyl, C₄ ⁻ ₇ cycloalkyl unsubstituted or substituted by at least one C₁ ⁻ ₄ alkyl group 1, or a phenyl group unsubstituted or substituted by at least one halogen atom, trifluoromethyl group, alkyl or alkoxy or alkylthio group containing from 1 to 4 carbon atoms, nitro or phenyl group), R⁵ represents hydrogen or C₁ ⁻ ₄ alkyl, with the proviso that, when B represents an oxygen or sulphur atom, Z represents a single bond and D represents an alkylene group containing from 1 to 5 carbon atoms] , and salts thereof possess a strong inhibitory activity on thromboxane synthetase from rabbit platelet microsomes, and are useful as therapeutically active agents for inflammation, hypertension, thrombus, cerebral apoplexy, asthma, myocardial infarction, cardiostenosis, cerebral infarction and acute cardiac death. The present invention relates to wherein: R¹ is a pyridyl group; R² is a phenyl, thienyl, furyl, naphthyl, benzothienyl or pyridyl group, which is unsubstituted or substituted by an alkoxy having 1 to 4 carbon atoms, an alkyl having 1 to 5 carbon atoms, an halogen, trifluoromethyl, an alkenyl having 2 to 5 carbon atoms or methylenedioxy; R³ is hydrogen, benzyl or an alkyl having 1 to 4 carbon atoms; one of R⁴ and R⁵ is hydrogen or an alkyl having 1 to 4 carbon atoms, and the other is phenyloxy, naphthoxy, alkyl having 1 to 8 carbon atoms, alkenyl having 2 to 8 carbon atoms, alkynyl having 2 to 8 carbon atoms, a cycloalkyl having 3 to 6 carbon atoms, a cycloalkenyl having 5 to 6 carbon atoms, or phenyl, naphthyl, 2-thienyl, 3-thienyl, 3-pyridyl, the alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, phenyl, naphthyl, 2-thienyl, 3-thienyl and 3-pyridyl being unsubstituted or substituted by hydroxyl, cyano, alkyl having 1 to 3 carbon atoms, alkoxy having 1 to 3 carbon atoms, halogen, phenyl or cyano-substituted phenyl, or a group represented by the formula, -S(O) m R⁶ (in which R⁶ is phenyl or an alkyl having 1 to 3 carbon atoms; m is an integer of 0 to 2), or R⁴ and R⁵ each combine with the other to represent one alkylene group comprising 1 to 6 methylene groups which may be substituted by alkyl having 1 or 2 carbon atoms, phenyl, pyridyl or thienyl; n is an integer of 2 to 6, or a pharmaceutically acceptable salt thereof. In the above general formula (I), as the pyridyl group represented by R¹ and R², there may be mentioned 2-pyridyl, 3-pyridyl and 4-pyridyl, and among these, 3-pyridyl group is preferred. With reference to the groups represented by R², the thienyl may be any of 2-thienyl and 3-thienyl, the furyl any of 2-furyl and 3-furyl, the naphthyl any of α-naphthyl and β-naphthyl, and the benzothienyl any of 2-benzothienyl, 3-benzothienyl, 4-benzothienyl, 5-benzothienyl, 6-benzothienyl and 7-benzothienyl. Referring to the substituents for the phenyl, thienyl, furyl, naphthyl, benzothienyl and pyridyl represented by R², examples of the lower alkoxy group of 1 to 4 carbon atoms include methoxy, ethoxy, n -propoxy, i -propoxy n -butoxy, i -butoxy and t -butoxy; examples of the lower alkyl group of 1 to 5 carbon atoms, include methyl, ethyl, n -propyl, i -propyl, n -butyl, i -butyl, t -butyl, n -pentyl and i -pentyl; examples of the halogen atom include fluoride, chlorine and bromine; and examples of the lower alkenyl group of 2 to 5 carbon atoms include vinyl, allyl and pentenyl. When the phenyl, thienyl, furyl, naphthyl, benzothienyl and pyridyl represented by R² contain substituents, such substituents can be introduced in arbitrary positions on the rings. As examples of the lower alkyl group of 1 to 4 carbon atoms represented by R³, R⁴ and R⁵, there may be mentioned methyl, ethyl n -propyl and n -butyl. Examples of the aryloxy group represented by R⁴ or R⁵ include phenyloxy, 1-naphthoxy and 2-naphthoxy. As examples of the lower aliphatic hydrocarbon group, having not more than 8 carbon atoms, there may be mentioned lower alkyl groups of 1 to 8 carbon atoms exemplified by methyl, ethyl, n -propyl n -butyl, n -pentyl, n -hexyl and n -heptyl, lower alkenyl groups of 2 to 8 carbon atoms exemplified by vinyl, allyl, 1-methylvinyl, 3-methyl-2-butenyl, 2-pentenyl, 2-hexenyl and 2-heptenyl, and alkynyl groups of 2 to 8 carbon atoms exemplified by ethynyl, 2-propynyl, 2-butynyl, 2-hexynyl and 2-octynyl, and, among others, alkyl groups of 1 to 4 carbon atoms, alkenyl groups of 2 to 5 carbon atoms and alkynyl groups of 2 to 8 carbon atoms are preferred. As examples of the alicyclic hydrocarbon group of not more than 6 carbon atoms, there may be mentioned those having not more than 6 carbon atoms, such as cycloalkyl groups of 3 to 6 carbon atoms being exemplified by cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl, and cycloalkenyl groups of 5 to 6 carbon atoms being exemplified by cyclo-1-pentenyl and cyclo-1-hexenyl. Examples of the aromatic group represented by R⁴ or R⁵ include phenyl, naphthyl, 2-thienyl, 3-thienyl and 3-pyridyl. The above-mentioned lower aliphatic hydrocarbon, alicyclic hydrocarbon and aromatic groups represented by R⁴ or R⁵ may have substituents such as hydroxyl, cyano, lower alkyl (e.g., those of 1 to 3 carbon atoms such as methyl and ethyl) and lower alkoxy groups (of 1 to 3 carbon atoms such as methoxy and ethoxy), halogen atoms (e.g., fluorine, chlorine and bromine), phenyl and cyano-substituted phenyl groups. As examples of the group of the formula -S(O)m R ⁶ represented by R⁴ or R⁵, there may be mentioned methylthio, ethylthio, isopropylthio, methylsulfinyl, ethylsulfinyl, methylsulfonyl, ethylsulfonyl, phenylthio, phenylsulfinyl, phenylsulfonyl and p -toluene-sulfonyl. when R⁴ and R⁵ combine and cooperate together to represent one alkylene group, such alkylene group comprises 1 to 6 methylene groups being joined to one another; when R⁴ and R⁵ cooperate together to represent one methylene group, it signifies that the carbon to be linked by R⁴ and R⁵ is bonded to the methylene group through the double bond; and when R⁴ and R⁵ cooperate together to represent a polymethylene group of 2 to 6 carbon atoms, it denotes that there is formed a ring with the carbon to be linked by R⁴ and R⁵. Further, such alkylene group may have substituents in arbitrary positions. Examples of such substituents include C₁ ⁻ ₂ alkyl groups , namely, methyl or ethyl, phenyl, pyridyl and thienyl groups, and these may be introduced in number of 1 to 2. The compounds of the general formula (I) may be addition salts with pharmacologically allowable organic acids or inorganic acids, and examples of such addition salts include salts with hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid, citric acid, succinic acid, maleic acid, fumaric acid, methanesulfonic acid, benzenesulfonic acid, etc. In addition, when R³ in the compounds (I) is a hydrogen atom, they may be alkali metal salts such as sodium and potassium salts, and alkaline-earth metal salts such as calcium salts. Representative examples of the compounds (I) include 2,2-dimethyl-7-phenyl-7-(3-pyridyl)-6-heptenoic acid, 2,2-dimethyl-8-phenyl-8-(3-pyridyl)-7-octenoic acid, 2,2-dimethyl-7-(2-thienyl)-7-(3-pyridyl)-6-heptenoic acid, 2,2-dimethyl-8-(2-thienyl)-8-(3-pyridyl)-7-octenoic acid and 2,2-dimethyl-7-(2-naphthyl)-7-(3-pyridyl)-6-heptenoic acid. The substituted vinylcarboxylic acid derivatives of the above general formula. (I) and salts thereof have a strong inhibitory action on the thromboxane A₂ synthetase solubilized and fractionated from platelet microsomes of humans,cows, horses, etc., and also exhibit, in mammals inclusive of humans, a strong action to inhibiting the biosynthesis of thromboxane A₂ (TXA₂) in vivo . Furthermore, the compounds (I) of the present invention exhibit the effect of increasing the production efficiency for the dilating I₂ (PGI₂) that shows the arterial smooth muscle relaxation action, platelet- aggregation inhibiting action or dissociation of platelet aggregation, etc. Thus, prostaglandin G₂ (PGG₂) or prostaglandin H₂ (PGH₂) is the important intermediate for thromboxane A₂, prostaglandin I₂ and other prostaglandins, and the compounds (I) of the present invention at very low concentrations (not greater than 3 x 10⁻⁸ mole) exhibit an inhibitory action against the converting enzyme (thromboxane A₂ synthetase) from PGH₂ or PGG₂ to thromboxane A₂, whereas they show no inhibitory action against the converting enzymes to the physiologically very useful prostaglandin I₂ (PGI₂) and other prostaglandins, for example PGI₂ synthetase and prostaglandin synthetase; they rather enhance the bioavailability of PGH₂ and PGG₂, and show stimulation of PGD₂ production in platelets and of PGI₂ in the presence of vascular endothelial cells. As is clear from the above, the substituted vinylcarboxylic acid derivatives of the general formula (I) inhibit selectively thromboxane A₂ (TXA₂) synthetase, while not exhibiting a suppressive action toward prostaglandin I₂ (PGI₂) synthetase, prostaglandin synthetase (cyclooxygenase) and various synthetases for prostaglandins. Also, the compounds of the present invention are extremely low in toxic effects towards,rats ,dogs, etc., and are characterized by a large difference between the lethal dose and the effective dose. In addition, the compounds of the present invention are less susceptible to a carbon-reduction reaction, via ω-oxidation, showing long lasting action in vivo ,and are therefore expected to exhibit the stable TXA₂ synthetase inhibiting action over a long period of time. consequently, the compounds of the present invention can reduce the amount of each dose, develop lessened side-effects even when repeatedly administered for a long period of time, and be given to mammals inclusive of humans for the prophylaxis or therapy of ischemic diseases (e.g., myocardial infarction, cerebral apoplexy, infarction in the kidney, lung and so forth, ulcers in the digestive tract, etc.), due to thrombosis caused by platelet aggregation or constriction of coronary arteries, brain and peripheral and circulatory vascular systems as well as various disorders (e.g., arteriosclerosis, hypertension, etc.) caused by TXA₂/PGI₂ imbalance. Referring to the method of administration, they are applicable orally, for example as tablets, capsules, powders, granules, etc.,and also can be administered parenterally as injections or pellets. As to the dosage, they are normally administered orally in 50 to 200 mg daily, or parenterally in 50 to 200 mg daily, being divided in one to three doses. Among the compounds of the formula (I), a compound of formula (I-1): wherein: R²' is a phenyl or thienyl group which may optionally be substituted by an alkoxy having 1 to 4 carbon atoms, an alkyl having 1 to 5 carbon atoms, an halogen, trifluoromethyl or methylenedioxy; one of R⁴ ' and R⁵ ' is hydrogen or an alkyl having 1 to 4 carbon atoms and the other is an alkyl having 1 to 8 carbon atoms or phenyl; and R³ and n are as defined in Claim 1 and pharmaceutically acceptable salts thereof are preferable from the viewpoint of inhibitory action of thromboxane A₂ synthetase. When the substituent of R²' is C₁ ⁻ ₄ alkoxy or C₁ ⁻ 5 alkyl it has the same meaning as in the case of R². When R⁴ ' and R⁵ ' represent C₁ ⁻ ₄ alkyl, they have the same meaning as R⁴ and R⁵. The novel compounds (I) of the invention and pharmaceutically acceptable salts thereof may be prepared by a method wherein a compound of the formula (XVI): is reacted with a compound of the formula (XVII): where: W is = CH ( CH₂ ) n X, Y is H, Z¹ is R⁴ and Z² is R⁵; o r W is = 0, Y is R¹ to R⁵ inclusive and n are defined above and X is halogen;or wherein a compound of the formula (XVIII): is reacted with a compound of the formula (VII): where W is = CH ( CH₂) n , Z¹ is R⁹ and Z² is H (R¹ to R³ inclusive n and X being as defined above, R⁹ being hydrogen, an alkyl having 1 to 4 carbon atoms, phenylthio or naphthylthio, and R¹⁰ being an alkyl having 1 to 8 carbon atoms, an alkenyl having 2 to 8 carbon atoms or an alkynyl having 2 to 8 carbon atoms); or wherein a compound of the general formula (XVIII): is reacted with a compound of the formula (IX): where W is =CH (CH₂) n , Z¹ is R¹¹ and Z² is H (R¹ to R³, inclusive and n being as defined above, R¹¹ being H or C₁ ⁻ ₄ alkyl and R¹² being C₁ ⁻ ₄ alkyl or phenyl or naphthyl); or wherein a compound of the general formula (XVIII): is reacted with a compound of the formula (XI): where W is =CH-(-CH₂-)n, Z¹ is R¹³ and Z² is H (R¹ to R³, inclusive and n being as defined above, R¹³ being hydrogen or an alkyl having 1 to 4 carbon atoms, and R¹⁴ and R¹⁵ each represent an alkyl having 1 to 8 carbon atoms, phenyl or naphthyl or combine with the other to represent one alkylene group comprising methylene groups joined in the number of 2 to 6); or wherein a compound of the general formula (XVIII): is subjected to dehydration (R¹ to R³ and R¹³ to R¹⁵, inclusive, and n being as defined above), and, where, desired said compound (I) is converted to its pharmaceutically acceptable salt. The compounds (I) of the present invention can be produced, for example, by any of the processes to be described below. [Production process 1] The compounds of the formula (I) can be obtained by reacting a compound of the general formula: (wherein R¹, R² and n are as defined hereinbefore; X is a h alogen atom) with a compound of the formula (III): (wherein R³, R⁴ and R⁵ are as defined hereinbefore). In the above general formula (II), examples of the halogen atom represented by X include bromine, iodine, etc. This reaction is conducted normally in an anhydrous solvent under an inert gas with a strong base compound. Examples of the solvent which is useful in this reaction include dimethylsulfoxide, dimethylformamide, hexamethylenephosphortriamide, tetrahydrofuran, diethyl ether, 1,2-dimethoxyethane and solvent mixtures selected therefrom. As the inert gas, use is made of argon, helium, nitrogen, etc. The reaction temperature varies depending upon the substituents R⁴ and R⁵, the kind of reaction solvent and the type of strong base to be used, etc., and is normally in the range of -70°C to 30°C. As the strong base compound, proper selection for utilization is made out of, for example, lithium diisopropylamide, potassium hydride, sodium hydride, sodium amide, potassium tert-butoxide, lithium isopropylcyclohexylamide, etc. The reaction normally goes to completion within 30 minutes to 3 hours. [Production process 2] Compounds of the formula (I-2): wherein R¹ to R³ and n are as defined above, and one of R⁷ and R⁸ is an hydrogen atom or an alkyl having 1 to 4 carbon atoms, and the other is an alkyl having 1 to 8 carbon atoms, an alkenyl having 2 to 8 carbon atoms or an alkynyl having 2 to 8 carbon atoms, a cycloalkyl having 3 to 6 carbon atoms, a cycloalkenyl having 5 or 6 carbon atoms, or phenyl, naphthyl, 2-thienyl, 3-thienyl or 3-pyridyl, the alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, phenyl, naphthyl, 2-thienyl, 3-thienyl or 3-pyridyl being unsubstituted or substituted by hydroxyl, cyano, alkyl having 1 to 3 carbon atoms, alkoxy having 1 to 3 carbon atoms, halogen, phenyl or cyano-substituted phenyl; can be obtained by reacting a compound of the formula (IV): (wherein R¹ and R² are as defined above) with a compound of the formula (V): wherein R³, R⁷, R⁸, and n are as defined above, and X - is an halogen ion. In the above formulae (I-2) and (V), the lower aliphatic hydrocarbon group, alicyclic hydrocarbon group of not more than 6 carbon atoms and aromatic group represented by R⁷ and R⁸ are as defined for R⁴ and R⁵. As examples of the halogen ion represented by X - , there may be mentioned chlorine, bromine and iodine ions. When R⁷ or R⁸ is C₁ ⁻ ₄ alkyl, R⁷ or R⁸ has the same meaning as R⁴ or R⁵, respectively. This reaction is normally carried out in an organic solvent in the presence of a base. As examples of the base, there may be mentioned n -butyl lithium, lithium diisopropyl amide, sodium hydride, potassium hydride, potassium tertbutoxide and sodium amide, and, among these, lithium diisopropyl amide, sodium hydride and sodium amide are preferably used. Examples of the solvent include ether, tetrahydrofuran, dimethylformamide, dimethylsulfoxide or solvent mixtures of not less than two kinds selected therefrom. This reaction is desirably conducted under an atmosphere of dry inert gas (e.g., nitrogen gas, argon gas, helium gas, etc.). The reaction temperature is -20°C to 50°C, preferably 0°C to 30°C. This reaction can be checked for how far the reaction proceeds by observing the disapperance of the characteristic color of phospholane, and goes to completion normally within the range of 1 to 6 hours. [Production process 3] Compounds of the formula (I-3) wherein R¹, R², R⁹ and R¹⁰ and n are as defined above), can be produced by reacting a compound of the formula (VI): (wherein R¹, R², R³, R⁹ and n are as defined hereinbefore) with a compound of the formula (VII): (wherein X is an halogen; and R¹⁰ is as defined hereinbefore). In the above general formulae (VI) and (I-3), the C₁ ⁻ ₄ alkyl group represented by R⁹ is as defined for the C₁ ⁻ ₄ alkyl group R⁴ or R⁵, and the arylthio group represented by R⁹ is phenylthio or naphthylthio. In the above general formulae (VII) and (I-3), furthermore, the lower aliphatic hydrocarbon group represented by R¹⁰ is as defined for the lower aliphatic hydrocarbon group R⁵. This reaction is normally carried out in a solvent in the presence of a base. Examples of the base include n-butyl lithium, lithium diisopropylamide, lithium isopropylcyclohexylamide, sodium hydride, potassium hydride and potassium tert-butoxide. As the solvent, use is made of, for example, ether, tetrahydrofuran, dimethylsulfoxide, hexamethylphosphortriamide or solvent mixtures of not less than two kinds selected therefrom. The reaction temperature, normally, is preferably -78°6 to 0°C, and the reaction time is normally 1 to 3 hours. [Production process 4] Compounds of the formula (I-4(: (wherein R¹, R², R³ and n are as defined above; R¹¹ is hydrogen or C₁ ⁻ ₄ alkyl; and R¹² being C₁ ⁻ ₄ alkyl or a phenyl or naphthyl group) can be obtained by reacting a compound of the formula (VIII) (wherein R¹, R², R³, R¹¹ and n are defined hereinbefore) with a compound of the formula (IX): (wherein R¹² is as defined above). In the above formulae (VIII) and (I-4), the lower alkyl group represented by R¹¹ is as defined for the lower alkyl group R⁴ or R⁵, and examples of the lower alkyl group represented by R¹² include those of 1 to 8 carbon atoms such as methyl, ethyl, n -propyl, isopropyl, n -butyl, n -pentyl, n -hexyl, and n -heptyl. This reaction is normally conducted in a solvent, such as tetrahydrofuran, diethyl ether and 1,2-dimethoxy-ethane, at the reaction temperature of -70° to 0°C, under an inert gas atmosphere and in the presence of lithium diisopropylamide or lithium isopeopylcyclohexylamide etc. The reaction time is 1 to 3 hours. [Production process 5] Compound of the formula (I-5): wherein R¹, R², R³, R¹³ to R¹⁵ and n are as defined above, can be obtained by reacting a compound of the formula (X): (wherein R¹, R², R³, R¹³ and n are as defined hereinbe fore) with a compound of the general formula (XI): (wherein R¹⁴ and R¹⁵ are as defined above). In the above general formulae (X) and (I-5), the C₁ ⁻ ₄ alkyl group represented by R¹³ is as defined for the C₁ ⁻ ₄ alkyl group R⁴ or R⁵, and examples of the C₁ ⁻ ₄ alkyl represented by R¹⁴ and R¹⁵ include those of 1 to 8 carbon atoms such as methyl, ethyl, n -propyl n -butyl, n -pentyl, n -hexyl and n -heptyl. The aromatic group is phenyl or naphthyl. When R¹⁴ and R¹⁵ are combined with each other to represent an alkylene group, such alkylene group comprises methylene groups joined in the number of 2 to 6, whereby said alkylene group forms a ring together with the carbon atom linked by R⁴ and R⁵. This reaction can be carried out under the same conditions as in the above-mentioned production process 4 in terms of the base, solvent, reaction temperature and inert gas being employed. [Production process 6] Compounds of the general formula (I-6): or of the general formula (I-7): (wherein R¹, R², R³, n, R¹³, R¹⁴ and R¹⁵ are as defined hereinbefore; R¹⁶ is a hydrogen atom or a C₁ ⁻ ₇ alkyl group and R¹⁷ is a C₁ ⁻ ₈ alkyl, phenyl or naphthyl or R¹⁶ and R¹⁷ combine and cooperate together to represent an alkylene group of 1 to 5 carbon atoms) can be obtained by subjecting a compound of the general formula: (wherein each of the symbols is as defined hereinbefore) to a dehydration reaction. This reaction is carried out in an inert solvent, such as methylene chloride, chloroform, ethyl acetate, toluene, ether and tetrahydrofuran, in the presence of an organic base such as pyridine and triethylamine and with the use of a dehydrating agent such as thionyl chloride or phosphorus oxychloride. The substituted vinylcarboxylic acid derivatives (I), as produced by the above procedures, can be separated and purified by ordinary means such as extraction, concentration, crystallization and liquid chromatography. Also, the compounds (I) belong to 3-substituted oiefin compounds, and, in some instances, occur in two geometrical isomers. Separation of the isomers, if necessary, can be effected by fractional crystallization, chromatography or a combination thereof, etc. When the compound of the general formula (I) is a carboxylic acid [in the formula (I), R³ is a hydrogen atom], it can be coverted to an ester form [in the formula (I), R³ is a lower alkyl group] by esterification, as the case may be, and conversely, in cases where the compound (I) is an ester form, it can be converted to a free carboxylic acid, if necessary. Each compound of the formula (I-I) has two geometrical isomers of the formulae: wherein each symbol has the meaning given above. In the following description of this invention, the compound wherein, as in the case of compounds represented by the formula (I-1a), the pyridine ring substituting one of the carbon atoms involved in the vinyl double bond and the hydrogen atom substituting the other carbon atom are disposed in the same direction is referred to as the E isomer and the compound wherein, as in the case of compounds represented by formula (I=1b), the pyridine ring substituting one of the carbon atoms involved in the vinyl double bond and the hydrogen atom substituting the other carbon atom are disposed in the opposite direction is referred to as the Z isomer. The Z isomer (I-1b) can be isomerized to the E isomer (I-1a) by an isomerization reaction which comprises heating the Z isomer in the presence of a mineral acid. The isomerization reaction is generally conducted either in water or in an aqueous organic solvent. This aqueous organic solvent should basically be a solvent that is not susceptible to mineral acids. Thus, for example, mixtures of water with acetic acid, formic acid, etc. may be mentioned. The mineral acid,may for example, be hydrochloric acid, sulfuric acid, phosphoric acid, hydrobromic acid, perchloric acid, methanesulfonic acid or the like, although hydrochloric acid, hydrobromic acid or phosphoric acid is preferably employed. This acid is generally used in the proportion of from 6 to 15 moles per mole of the starting compound (I-1b). The reaction temperature is generally from 50 to 140°C and preferably from 100 to 130°C. At a lower temperature, the reaction is undesirably retarded. The reaction time varies with the kind and amount of the acid catalyst used and the heating temperature. Generally, such reaction conditions are selected as would reach an equilibrium of acid isomerization in from 10 to 40 hours. This reaction is an equilibrium reaction between the E isomer (I-1a) and Z isomer (I-1b), and, by subjecting either the E isomer or the Z isomer,or an optional mixture of E and Z isomers,to the isomerization reaction, it can be converted to a mixture consisting of from 60 to 70% of E isomer (I-1a) and from 30 to 40% of Z isomer (I-1b). Since, as aforementioned, the E isomer is pharmacologically superior to the Z isomer, this reaction is advantageously applied to mixtures containing 40% or more of Z isomer. When this reaction is conducted using a compound of general formula (I-1b) wherein R³ is a lower alkyl group as a starting material, a hydrolysis reaction takes place concurrently to give the Compound (I-1a) wherein R³ is hydrogen. The product compound (I-1a) (E isomer) obtainable by this reaction can be isolated and purified by such procedures as, for example, adjusting the reaction mixture to its isoelectric point(pH 5.0 to 6.0) with aqueous ammonia, sodium hydroxide ,potassium hydroxide or the like, extracting the product compound with an organic solvent such as ethyl acetate, chloroform, dichloromethane or the like, and subjecting the extract to a conventional purification procedure such as crystallization or chromatography. The yield of this isomerization reaction can be improved by repetitive application thereof to the residual Z isomer-rich mixture remaining after isolation, for example,by fractional crystallization, of E isomer (I-1a). When the compounds of general formula (I-Ia) and (I-1b) are carboxylic acids [in formulae (II) and (III), R³ is a hydrogen atom], these acids can, if necessary, be esterified to the corresponding esters [in formulae (I-1a) and (I-1b), R² is a lower alkyl group]. Conversely, if the compounds (I-1a) and (I-1b) are esters, they can be hydrolyzed to the free carboxylic acids. The compound (I-1) obtained in the reaction of compound (II) with compound (III), or in the reaction of compound (IV) with compound (V), is a substantially equimolar mixture of E and Z isomers. This mixture can be directly used in the practice of this invention but it is of course possible to separate she E and Z isomers from each other e.g. by fractional recrystallization or liquid chromatography and to subject the Z isomer alone to the isomerization reaction mentioned above. The compounds of the above general formula (IV) can be produced, for example as illustrated in the following manner, by reacting an organic lithium compound with an aldehyde compound to yield a compound (XIV), and then reacting said compound (XIV) with manganese dioxide or dimethyl-sulfoxide-oxalic chloride. The compounds of the above general formula (II) can be produced, for example, by reducing a compound of the general formula: (wherein R¹, R², R³ and n are as defined hereinbefore) with lithium aluminum hydride, etc., to convert it into the corresponding alcohol form, and a subsequent halogenation reaction. Also, the triphenylphosphonium salt of the above general formula (V) can be produced, for example, by the following reaction: The reference examples, examples and experiments are described below to illustrate more specifically the present invention. With reference to the designation of isomers, the compounds in which the 3-pyridyl group and olefinic proton at the double bond substituted by the 3-pyridyl group are in the same direction are called "(E)-isomer", and the compounds in which the 3-pyridyl group and the olefin proton are in the opposite direction are called "(Z)-isomer". In the tables to be shown in the following, the symbols denote the following groups, respectively: 3-Py: 3-pyridyl group; 2-Th, 3-Th: 2-thienyl group, 3-thienyl group; Ph: phenyl group; Me: methyl group; Et: ethyl group; PhCH₂: benzyl group; PhO: phenoxy group; i-Pr-S: isopropylthio; MeS-: methylthio; PhS: phenylthio. Nuclear magnetic resonance spectra were measured on an EM-390 (Varian Associates, U.S.A.) utilizing CDCℓ₃ as solvent. Reference Example 1 Methyl (E+Z)-6-phenyl-6-(3-pyridyl)-5-hexenoate (23 g) was dissolved in anhydrous tetrahydrofuran (100 mℓ), and the solution was cooled with ice at 5°C. Lithium aluminum hydride (4 g) was gradually added to the solution, followed by stirring at room temperature for 3 hours. After the completion of the reaction, saturated aqueous potassium sodium tartrate was added to decompose the excessive regent, whereby the inorganic materials were solidified. The organic layer was separated, and the remaining inorganic substance was washed with ethyl acetate. The organic layer and ethyl acetate layer were combined and concentrated under reduced pressure. The residue was chromatographed on a column of silica gel, and the elution was performed with ethyl acetate to yield (E+Z)-6-phenyl-6-(3-pyridyl)-5-hexen-1-ol (16 g). The alcohol form (15 g) was dissolved in 47% aqueous hydrobromic acid (100 mℓ) and the solution was heated at 100°C for 18 hours to allow the reaction to proceed. After the cooling, the reaction solution was adjusted to pH 8 by adding sodium hydrogen carbonate, and the resultant product was extracted with ethyl acetate. The organic layer was worked up in the usual manner, and the ethyl acetate was evaporated in vacuo . The residue was chromatographed on silica gel, using ethyl acetate:isopropyl ether (1:1) as eluant to yield (E+Z)-1-bromo-6-phenyl-6-(3-pyridyl)-5-hexene (15g). NMR (δ value): 8.50 (2H,m), 7.30 (7H,m), 6.16 (1/2H,t,7Hz), 6.08 (1/2H,t,7Hz), 3.34 (2H,t,6Hz), 2.05 (3H,m), 1.80 (3H,m) The bromide compound (15 g) was dissolved in acetone (100 mℓ), and sodium iodide (25 g) was added to the solution, followed by stirring at room temperature for 1 hour. After the completion of the reaction, water (50 mℓ) was added, followed by extraction with ethyl acetate. The organic layer was washed with water, dried and concentrated under reduced pressure. The residue was chromatographed on silica gel using ethyl acetate : isopropyl ether (1 : 1) as eluant to give the Z-isomer at first and then the E isomer [(E)-1-iodo-6-phenyl-6-(3-pyridyl)-5-hexene: NMR (δ value), 8.50 (2H,m), 7.30 (7H,m), 6.08 (1H,t,7Hz), 3.15 (2H,t,6Hz), 2.02 (2H,m), 1.80 (2H,m); (Z)-1-iodo-6-phenyl-6-(3-pyridyl)-5-hexene: NMR (δ value), 8.50 (2H,m), 7.31 (7H,m), 6.16 (1H,t,7Hz), 3.18 (2H,t,6Hz), 2.00 (2H,m), 1.78 (2H,m)]. Reference Example 2 In dichloromethane (100 mℓ) was dissolved (E+Z)-5-phenyl-5-(3-pyridyl)-4-penten -1-ol (prepared from 3-benzoyl-pyridine and 4-hydroxybutyltriphenylphosphonium bromide in accordance with the Wittig reaction)[NMR (δ value): 8.34-8.60 (2H,m), 7.1-7.6 (7H,m), 6.0-6.3 (1H,m), 3.40 (2H,t), 2.0-2.4 (2H,m), 1.5-1.9 (2H,m)] (12 g), and the solution was cooled at 0°C. Triethylamine (6.0 g) was added to the solution, followed by stirring under the same conditions. A solution of methanesulfonyl chloride (6.2 g) in dichloromethane (20 mℓ) was added to the solution. After the completion of the reaction, water (100 mℓ) was added, followed by thorough shaking. The organic layer was separated, washed with water, dried and evaporated under reduced pressure to dryness. Acetone (100 mℓ) and sodium iodide (8 g) were added to the residue, and the reaction was allowed to proceed at room temperature for 3 hours. After the completion of the reaction, the acetone was removed under reduced pressure, and ethyl acetate (100 mℓ) and water (50 mℓ) were added to the residue to extract the products. The organic layer was washed with water, dried and concentrated under reduced pressure. The residue was chromatographed on silica gel using isopropyl ether : ethyl acetate (1 : 1) as eluent to give the Z isomer at first and then the E isomer [(E)-1-iodo-5-phenyl-5-(3-pyridyl)-4-pentene: NMR (δ value), 8.35-8.60 (2H,m), 7.1-7.6 (7H,m), 6.07 (1H,t,7hz), 3.42 (2H,t), 3.27 (2H,t), 2.35 (2H,m); (Z)-1-iodo-5-phenyl-5-(3-pyridyl)-4-pentene: NMR (δ value), 8.35-8.60 (2H,m), 7.1-7.6 (7H,m), 6.20 (1H,t,7Hz), 3.43 (2H,t), 3.28 (2H,t), 2.36 (2H,m). Reference Example 3 Production of 5-carboxy-5,5-dimethylpentyltriphenyl-phosphonium bromide. a) Ethyl 6-acetoxy-2,2-dimethylhexanoate Diisopropylamine (8.25 mℓ) was dissolved in anhydrous tetrahydrofuran. (100 mℓ) under an argon atmosphere, and the solution was cooled at -70°C. 1.6 M n -butyllithium hexane solution (37 mℓ, 60 mmole) was added dropwise to the solution, to which a solution of ethyl isobutyrate (5.6 g, 48 mmole) in anhydrous tetrahydrofuran (5 mℓ) was then added, while maintaining the reaction temperature at not higher than -60°C. After stirring was continued for 30 minutes under the same reaction conditions, a solution of 4-acetoxybutyl iodide (12 g, 50 mmole) in hexamethylphosphortriamide (5 mℓ) was added dropwise to the reaction solution, and the reaction was allowed to proceed until the mixture rose to room temperature. After the completion of the reaction, 2N hydrochloric acid (10 mℓ) was added, and the mixture was concentrated under reduced pressure. The resulting product was dissolved in ethyl acetate (100 mℓ), and the organic layer was washed with water, dried and concentrated under reduced pressure. The residue was chromatographed on a column of silica gel using isopropyl ether to give ethyl 6-acetoxy-2,2-dimethylhexanoate (5.6 g, 50%). b) 6-Bromo-2,2-dimethylhexanoic acid 6-Acetoxy-2,2-dimethylhexanoic acid (4.5 g) was dissolved in 47% aqueous hydrobromic acid (25 mℓ), and the solution was heated at 130°C for 4 hours. After the completion of the reaction, water (100 mℓ) was added to the solution, and the product was extracted with ether. The organic layer was washed with water, dried and concentrated under reduced pressure. The residue was chromatographed on a column of silica gel, and development with isopropyl ether yielded 6-bromo-2,-2-dimethylhexanoic acid (4 g, 91%). c) 5-Carboxy-5,5-dimethylpentyltriphenylphosphonium bromide. 6-Bromo-2,2-dimethylhexanoic acid (3.8 g, 17 mmole) and triphenylphosphine (4.9 g, 18.7 mmole) were dissolved in acetonitrile (30 mℓ), and the solution was heated under reflux for 20 hours. After the completion of the reaction, the solvent was removed under reduced pressure, and the residue was treated with toluene, followed by thorough stirring. The insolubles were separated from the toluene solution, and crystallized from ethyl acetate to give 5-carboxy-5,5-dimethylpentyltriphenylphosphonium bromide (4.8 g, 58%) [NMR (δ value): 1.10 (6H,s), 1.4-1.6 (6H), 3.4-3.8 (2N)]. Reference Example 4 Production of 5-carboxy-5-methylpentyltriphenyl-phosphonium bromide. a) 2-Methylcaprolactam. 1.6 M n -butyllithium-hexane solution (28.9 mℓ, 46.2 mmole) was added dropwise to a solution of diisopropylamine (6.5 mℓ, 46.4 mmole) in tetrahydrofuran (50 mℓ) at -60°C under an argon atmosphere, with stirring. 10 minutes later, a solution of caprolactone (5.0 9, 43.8 mmole) in tetrahydrofuran (10 mℓ) was added dropwise to the solution. After the reaction was allowed to proceed for 20 minutes under the same reaction conditions, a solution of methyl iodide (7.5 g, 52.8 mmole) in hexamethylphosphoramide (9.2 mℓ) was added gradually to the reaction solution, and stirring was continued for 1 hour after the dropwise addition while maintaining the reaction mixture at -40° to -45°C. Saturated aqueous ammonium chloride solution (20 mℓ) was added to the reaction solution to terminate the reaction, and water (100 mℓ) was added to the mixture, followed by extraction of the product with ethyl acetate. The organic layer was washed with water, dried and concentrated. The residue was chromatographed on a column of silica gel, and development with isopropyl ether yielded 2-methylcaprolactam (3.7 9, 66%) [NMR (δ value): 1.18 (3H, d, 6Hz), 2.5-2.9 (1H,m), 4.18-4.34 (2H,m)]. b) 6-Bromo-2-methylhexanoic acid To 2-methylcaprolactone (1.89, 14 mmole) was added a solution mixture of 47% aqueous hydrobromic acid (10.5 mℓ) and concentrated sulfuric acid (2.6 mℓ), and the reaction was conducted under heating at 130°C for 3 hours. After the reaction solution was cooled, water was added, and the product was extracted with ether. The organic layer was washed with water, dried and the solvent was evaporated in vacuo . The residue was chromatographed on a column of silica gel using isopropyl ether to give 6-bromo-2-methylhaxanoic acid (1.56 g, 53.3%) [NMR (δ value): 1.18 (3H,d,6Hz), 2.25-2.8 (1H,m), 3.40 (2H,t,6Hz), 11.56 (1H,COOH)]. c) 5-Carboxy-5-methylpentyltriphenylphosphonium bromide. A solution of 6-bromo-2-methylhexanoic acid (1.08 9, 5.17 mmole) and triphenylphosphine (1.42 g, 5.4 mmole) in toluene (5 mℓ) was heated under reflux for 18 hours. After the solution was cooled, the crystals which separated out were collected by filtration and washed with toluene and ethyl acetate to yield 5-carboxy-5-methylpentyltriphenyl-phosphonium bromide (1.6 g, 64%). Reference Example 5 Production of 5-carboxy-5-phenylpentyltriphenyl-phosphonium bromide a) Ethyl 6-acetoxy-2-phenylhexanoate. Diisopropylamine (2.4 g, 23.8 mmole) was dissolved in anhydrous tetrahydrofuran (50 mℓ) under argon, and the solution was cooled at -70°C. 1.6M n -butyl-lithium-hexane solution (14.8 mℓ, 23.7 mmole) was added dropwise to the solution, followed by stirring at -70°C for 10 minutes. Tetrahydrofuran (10 mℓ) solution containing ethyl phenylacetate (3.24g, 20 mmole) was added, while maintaining the reaction solution at not higher than -60°C. After stirring was continued for 30 minutes under the same conditions, a solution of 4-acetoxypentyl iodide (4.8 g, 20 mmole) in hexamethylphosphortriamide (4 mℓ) was added dropwise to the reaction solution. Following the dropwise addition, stirring was continued at -70°C for another 1 hour, and the reaction temperature was allowed to rise to room temperature. 2N hydrochloric acid (30 mℓ) was added, and the product was extracted with isopropyl ether. The organic layer was washed with water, dried and concentrated under reduced pressure. The residue was chromatographed on silica gel, and development was effected with isopropyl ether hexane (1 : 1) to yield ethyl 6-acetoxy-2-phenylhexanoate (5 g, 90%). b) 6-Bromo-2-phenylhexanoic acid Ethyl-6-acetoxy-2-phenylhexanoate (22 g) was dissolved in 47% aqueous hydrobromic acid (100 mℓ), and the solution was heated at 130°C for 4 hours. After the completion of the reaction, the solution was cooled, and aqueous sodium chloride (300 mℓ) was added, followed by extraction of the product with isopropyl ether. The organic layer was washed with water, dried and concentrated under reduced pressure. The residue was chromatographed on a column of silica gel, and development was effected with isopropyl ether to give 6-bromo-2-phenylhexanoic acid (16 g, 75%). c) 5-Carboxy-5-phenylpentyltriphenylphosphonium bromide. 6-Bromo-2-phenylhexanoic acid (16 g, 59 mmole) and triphenylphosphine (20 g, 76 mmole) were dissolved in acetonitrile (100 mℓ), and the solution was heated at 100°C for 18 hours. After the completion of the reaction, the solution was cooled and the solvent removed under reduced pressure. The residue was washed three times with toluene, whereby crystals separated out. The crystals were recrystallized from ethyl acetate to give 5-carboxy-5-phenylpentyltriphenylphosphonium bromide (21 g, 67%, m.p. 210-215°C) Example 1 (Production process 1) Procedure A: Diisopropylamine (0.6 g, 6 mmole) was dissolved in tetrahydrofurane (20 mℓ) under argon, and the solution was cooled at -70°C. 1.6M n -butyl lithium-hexane solution (4 mℓ) was added dropwise to the solution, and stirring was continued for 10 minutes under the same reaction conditions. A solution of methyl cyclohexanecarboxylate (0.86 g, 5.5 mmole) in tetrahydrofurane (2 mℓ) was added to the solution, and the mixture was stirred at -70°C for 15 minutes. To the mixture was added dropwise a solution of (E)-6-phenyl-6-(3-pyridyl)-1-iodo-5-hexene (1.8 g, 5 mmole) in hexamethyl-phosphoramide(3 mℓ). The reaction temperature was allowed to rise gradually to room temperature, and stirring was continued for 30 minutes under the same conditions. After the completion of the reaction, water was added, and the product was extracted with ethyl acetate. The organic layer was worked up by the usual procedure, and the crude product was chromatographed on silica gel. Development was effected with isopropyl ether : ethyl acetate (2 : 1) to give methyl (E)-2,2-(1,5-pentamethylene)-8-phenyl-8-(3-pyridyl)-7-octenoate (1-h) (1.2 g). Procedure B: Methyl p-methylphenylsulfonylacetate (0.43 g, 2 mmole) was dissolved in dimethylformamide, and,after the solution had been cooled to 0°C under argon, sodium hydride (0.1 g) was added, followed by stirring for 10 minutes. A solution of (Z)-6-phenyl-6-(3-pyridyl)-1-iodo-5-hexene (0.8 g) in dimethylformamide (4 mℓ) was added to the reaction solution, and the reaction was carried out at room temperature for 3 hours. After the completion of the reaction, water (30 mℓ) was added, and the product was extracted with ethyl acetate. Working up in the usual procedure, the resulting product was chromatographed on silica gel, and development was effected with isopropyl ether : ethyl acetate (1 : 1) to yield methyl (Z)-8-phenyl-8-(3-pyridyl)-2-(p-methylphenylsulfonyl)-7-octenoate (1-c) (0.6 g, 61%). Procedure C: Methyl (E)-2,2-(1,5-pentamethylene)-8-phenyl-8-(3-pyridyl)-7-octenoate (1-h) (0.2 g) was dissolved in aqueous methanol (40 mℓ), and lithium hydroxide (0.3 g) was added, followed by heating under reflux for 48 hours. After the completion of the reaction, the solvent was removed under reduced pressure, and the residue was adjusted to pH 6 with 2N hydrochloric acid. The product was extracted with ethyl acetate, and the extract was washed with water, dried and concentrated under reduced pressure. The residue was chromatographed on silica gel, and development was effected with ethyl acetate, whereby there was obtained (E)-2,2-(1,5-pentamethylene)-8-phenyl-8-(3-pyridyl)-7-octenoic acid (1-f) (0.18 g) from the eluate resulting after the first effluent was discarded. By following the procedures as described in the above example, there were produced the compounds (1-a through 1-u) shown in Table I, as follows; Example 2 (Production Process 2) Procedure A: Sodium hydride (2.5 9, 60% oil dispersion) was washed with hexane, to make clean of the oil, and dried under reduced pressure. Dimethylsulfoxide (25 mℓ) was added to it, and the mixture was heated under argon at 80°C for 1 hour to produce dimsyl anions. The reaction solution was cooled at 10°c, and 5-carboxy-5,5-dimethylpentyltriphenylphosphonium bromide (8 g, 16 mmole) was added, followed by stirring at room temperature for another 10 minutes. A dimethylsulfoxide solution (5 mℓ) containing 3-benzoylpyridine (3 g, 16 mmole) was added dropwise to the mixture solution, and, after the completion of the dropwise addition, stirring was continued at room temperature for 30 minutes. Water (50 mℓ) was added to the mixture, which was then shaken. The organic layer was separated, and the water layer was adjusted to pH 6.0 with 2N hydrochloric acid. The product was extracted three times with ethyl acetate (50 mℓ). The ethyl acetate layers were combined, washed with water, dried (over magnesium sulfate) and concentrated under reduced pressure. The residue was chromatographed on a column of silica gel, and development was effected with ethyl acetate to yield (E)+(Z)-2,2-dimethyl-7-phenyl-7-(3-pyridyl)-6-heptenoic acid(2-a, 2-b) (2.2. g). Procedure B: 5-Carboxy-5,5-dimethylpentyltriphenylphosphonium bromide (3 g, 6 mmole) was dissolved in anhydrous dimethyl-sulfoxide (30 mℓ) under a nitrogen atmosphere, and sodium hydride (0.25 g, 64 mmole) was added to the solution at 30 to 35°C followed by stirring at 25 to 30°C for 30 minutes. 3-Benzoylpyridine (0.9 g, 5 mmole) was added to the solution, followed by stirring at room temperature for another 1 hour. Water (100 mℓ) and toluene (100 mℓ) were added to the reaction solution, the organic layer was separated, and the water layer was adjusted to pH 6.0 with 2N hydochloric acid. The product was extracted with ethyl acetate, and the ethyl acetate layer was washed with water, dried and concentrated under reduced pressure. The residue was chromatographed on a column of silica gel, and development was effected with ethyl acetate to yield (E+Z)-2,2-dimethyl-7-phenyl-7-(3-pyridyl)-6-heptenoic acid (2-a, 2-b) (1.36 g, 88%). Method 1: (E+Z)-2,2-dimethyl-7-phenyl-7-(3-pyridyl)-6-heptenoic acid (622 mg, 2 mmole) was dissolved in hexamethylphosphotriamide (10 mℓ), and potassium hydroxide (120 mg) and benzyl bromide (350 mg) were added to the solution, followed by stirring at room temperature. After the completion of the reaction, water (50 mℓ) was added to the reaction solution, and the product was extracted with ethyl acetate. The organic layer was washed with water, dried and concentrated under reduced pressure. The residue was chromatographed on silica gel, and development with ethyl acetate : isopropyl ether (1: 1)gave benzyl (Z)-2,-2-dimethyl-7-phenyl-(3-pyridyl)-6-heptenoate (2-g) (262 mg) at first, and then benzyl (E)-2,2-dimethyl-7-phenyl-7-(3-pyridyl)-6-heptenoate (2-f)(282 mg). Method 2: (E+Z)-2-phenyl-7-(3-pyridyl)-7-(2-thienyl)-6-heptenoic acid (660 mg) was dissolved in ethanol (10 mℓ), and thionyl chloride (450 mg) was added to the solution under ice-cooling, followed by allowing the mixture to stand at room temperature for 5 hours. The reaction solution was concentrated under reduced pressure, and the residue was treated with water. The mixture was neutralized by adding sodium carbonate, and the product was extracted with ethyl acetate. The organic layer was washed with water, dried, and concentrated. The residue was chromatographed on silica gel, and development was effected with acetic acid : isopropyl ether (2 : 1) to yield at first ethyl (Z)-2-phenyl-7-(3-pyridyl)-7-(2-thienyl)-6-heptenoate (2-i)(220 mg) and then ethyl (E)-2-phenyl-7-(3-pyridyl)-7-(2-thienyl)-6-heptenoate (2-h)(235 mg). By following the procedures as described in the above Procedures A and B and Methods 1 and 2, there were produced the compounds (2-a through 2-n) to be shown in Table II. Example 3-1 (Production Process 3) A solution of diisopropylamine (0.21 mℓ, 1.46 mmole) in tetrahydrofurane (3 mℓ) was cooled at -60°c under argon, and a hexane solution of n -butyl lithium (1.6M, 0.92 mℓ, 1.46 mmole) was added dropwise to the solution. After stirring for 10 minutes, a solution of methyl (E)-7-phenyl-7-(3-pyridyl)-6-heptenoate (360 mg, 1.22 mmole) in tetrahydrofuran (2 mℓ) was added dropwise to the solution, followed by stirring at -60° to -70°C for 20 minutes. Subsequently, methyl iodide (0.12 mℓ, 1.83 mmole) was added, and the reaction was allowed to proceed at the same temperature for 1 hour. Saturated aqueous ammonium chloride was added to the reaction mixture, and the product was extracted with ethyl acetate. The organic layer was washed with water, dried (magnesium sulfate) and concentrated. The residue was chromatographed on silica gel, and development was effected with isopropyl ether: ethyl acetate (7 : 3) to yield methyl (E)-2-methyl-7-phenyl-7-(3-pyridyl)-6-heptenoate (3-a)(270 mg, 71.6 %). The compounds (3-a through 3-p) as shown in Table III-1 were produced in accordance with the above procedure. Example 3-2 Methyl (E)-2-methyl-7-phenyl-7(3-pyridyl)-6-heptenoate (270 mg, 0.87 mmole) was dissolved in methanol (2 mℓ), and sodium hydroxide (300 mg) and water (1 mℓ) were added to the solution, followed by allowing the reaction to proceed at 80°C for 2 hours. After the reaction solution was cooled, water and then 2N hydrochloric acid were added to adjust to pH 5.0, and the product was extracted with ethyl acetate. The organic layer was washed with water, dried (magnesium sulfate) and concentrated. The residue was chromatographed on silica gel, and development was effected with ethyl acetate to yield (E)-2-methyl-7-phenyl-(3-pyridyl)-6-heplenoic acid (3'-a)(217 mg, 84%). The compounds (3'-a through 3'-q) as shown in Table III-2 were produced in accordance with the above procedure. Example 4 (Production Process 4) Diisopropylamine (0.8 g, 8 mmole) was dissolved in tetrahydrofuran (10 mℓ) under argon, and the solution was cooled at -70°c, followed by adding dropwise 1.6M n-butyl lithium-hexane solution (5 mℓ) and stirring for 5 minutes. A solution of methyl (E)-7-phenyl-7-(3-pyridyl)-6-heptenoate (1.2 g, 4 mmole) in tetrahydrofuran (2 mℓ) was added dropwise to the reaction solution under the same conditions. 15 minutes later, a solution of phenyl disulfide (1 g, 5 mmole) in hexamethylphosphoramide (1 mℓ) was added dropwise under the same conditions. After the reaction was conducted for 30 minutes, 2N hydrochloric acid (5 mℓ) was added, and the reaction solution was restored to room temparature, followed by adjusting to pH 8 with aqueous sodium hydrogencarbonate. The product was extracted with ethyl acetate, and the organic layer was washed with water, dried and concentrated. The residue was chromatographed on silica gel, and development was effected with isopropyl ether: ethyl acetate (1:1) to yield methyl (E)-2-phenylthio-7-phenyl-7-(3-pyridyl)-6-heptenoate (4-e)(1.4 g, 85%). The compounds (4-a through 4-i) as shown in Table IV were produced in accordance with the above procedure. Example 5 Procedure A (Production process 5): Diisopropylamine (0.8 g, 8 mmole) was dissolved in tetrahydrofuran (10 mℓ) under argon, and the solution was cooled at -70°C, followed by adding dropwise 1.6M n -butyl lithium-hexane solution (5 mℓ) and stirring for 5 minutes. A tetrahydrofuran (2 mℓ) solution containing methyl 7-phenyl-7-(3-pyridyl)-6-heptenoate (1.19 g, 4 mmole) was added dropwise to the reaction solution. After stirring for 15 minutes under the same reaction conditions, acetone (0.5 mℓ) was added, and the reaction was carried out for another 10 minutes. Subsequently, 2N hydrochloric acid (5 m2) was added to terminate the reaction, and the temperature of the solution was allowed to rise to room temperature, followed by adding aqueous sodium hydrogencarbonate to adjust to pH 8. The product was extracted with ethyl acetate, and the organic layer was washed with water and dried. The residue was chromatographed on silica gel using isopropyl ether: ethyl acetate (1: 1) to yield methyl (E)-2-(1-hydroxy-1-methylethyl)-7-phenyl-7-(3-pyridyl)-6-heptenoate (5-a)(1.2 9). Procedure B (Production process 6): Methyl (E)-2-(1-hydroxy-1-methylethyl)-7-phenyl-7-(3-pyridyl)-6-heptenoate (0.3 g, 0.89 mmole) was dissolved in dichloromethane (10 mℓ), and the solution was cooled at -10°C. Thionyl chloirde (0.15 mℓ) was added to the solution, followed by adding pyridine (0.4 mℓ) and stirring for 10 minutes under the sane reaction conditions. After the completion of the reaction, aqueous sodium hydrogencarbonate(5 mℓ) was added, and the product was extracted with ethyl acetate. The organic layer was worked up in the usual procedure, and the crude product was chromatographed on silica gel, followed by elution with isopropyl ether : ethyl acetate (1 : 1) to yield methyl (E)-2-(1-methylethenyl)-7-phenyl-7-(3-pyridyl)-6-heptenoate (5-e) (0.15 g, 70%). The compounds (5-a through 5-m) as shown in Table V were produced in accordance with the above Procedure A or B. Example 6 1) (Z)-2,2-dimethyl-7-(3-pyridyl)-7-(2-thienyl)-6-heptenoic acid (1.0g) was heated in 50% aqueous phosphoric acid (20 ml) at 100°C for 20 hours, and the product was separated and extracted in the conventional manner. High performance liquid chromatography of this crude product revealed that its E isomer/Z isomer ratio was E/Z = 56:23. The crude product was separated in the same manner as Example 2 to give (E)-2,2-dimethyl-7-(3-pyridyl)-7-(2-thienyl)-6-heptenoic acid (0.48 g). Nuclear magnetic resonance spectrum : 1.19(3H,s), 1.21(3H,s), 1.52(4H,m), 2.04(2H,m), 6.06(1H,t,7Hz), 6.66(1H,m), 7.30(4H,m), 8.56(2H,m), 12.0(1H,COOH). 2) (Z)-2,2-dimethyl-7-phenyl-7-(3-pyridyl)-6-heptenoic acid (0.1g) was dissolved in 18% aqueous hydrochloric acid (1 ml) and the solution was heated at 100°C for 21 hours. Extraction, separation and concentration in the conventional manner gave the crude product. High performance liquid chromatography of this crude product revealed that its E isomer/Z isomer ratio was E/Z = 63:28. This crude product (85 mg) was subjected to preparative high performance chromatography to give (E)-2,2-dimethyl-7-phenyl-7-(3-pyridyl)-6-heptenoic acid (46 mg). Nuclear magnetic resonance spectrum: 1.18(6H,s), 1.50(4H,m), 2.12(2H,m), 6.12(1H,t,7Hz), 7.20(6H,m), 7.40(1H,dt,2Hz,7Hz), 8.44(1H,dd,2Hz,4Hz), 8.56(2H,d,2Hz), 9.82(1H,COOH). 3) (Z)-2,7-diphenyl-7-(3-pyridyl-6-heptenoic acid (200 mg) was dissolved in 50% aqueous phosphoric acid (2 ml) and the reaction was allowed to proceed with heating at 100°C for 20 hours. After completion of the reaction, the product was extracted, washed and concentrated in the same manner. High performance liquid chromatography of an aliquot of the residue revealed that its E isomer/Z isomer ratio was 58:27. The E/Z mixture was subjected to preparative high performance liquid chromatography. The E isomer (110 mg) and Z isomer (61 mg) were thus independently obtained. Examples of Pharmaceutical Composition All the materials were mixed and filled into a gelatin capsule. A mixed solution of (1) and (2) was prepared and filled into a soft capsule in a conventional manner. All the materials were mixed and compressed by a tabletting machine to prepare a tablet in accordance with a conventional manner. Experiment 1 Inhibitory Action on Thromboxane A₂(TXA₂) Synthetase As a specimen of TXA₂ synthetase there were employed horse platelet microsomes treated with indomethacin (indomethacin-treated horse platelet microsomes: IPM), which were prepared according to the method described by Needleman et al . (Science 193 163, 1976). To 60 µl of 50 mM tris-buffer solution (pH 7.5) of IPM (containing 140 µg as protein) was added 60 µl of the buffer solution or the solution containing the test compounds at various concentrations. The mixtures were left standing for 5 minutes at room temperature. Then, at 0°C to 100 µl portion of the mixture was added 20 µl of the buffer solution containing 30 ng of prostaglandin H₂ (PGH₂). The mixtures were left standing for 5 minutes at 0°C to cause formation of thromboxane A₂(TXA₂). The reaction of thromboxane A₂ production was stopped by the addition of 500 µl of the tris-buffer to the mixture. Using 50 µl of the mixtures, the quantitative determination of thromboxane B²(TXB₂), a stable metabolite of TXA₂, was done by means of the radioimmunoassay (Shibouta et al ., Biochem. Pharmacol. 28 3601, 1979). The inhibitory activity of the compounds on TXA₂-synthetase was determined from the difference in the production of TXB₂ between the test group and the control group. The results on typical compounds are shown by Table VI below:

Claims: A compound of the formula (I): wherein: R¹ is a pyridyl group; R² is a phenyl, thienyl, furyl, naphthyl, benzothienyl or pyridyl group, which is unsubstituted or substituted by an alkoxy having 1 to 4 carbon atoms, an alkyl having 1 to 5 carbon atoms, an halogen, trifluoromethyl, an alkenyl having 2 to 5 carbon atoms or methylenedioxy; R³ is hydrogen, benzyl or an alkyl having 1 to 4 carbon atoms; one of R⁴ and R⁵ is hydrogen or an alkyl having 1 to 4 carbon atoms, and the other is phenyloxy, naphthoxy, alkyl having 1 to 8 carbon atoms, alkenyl having 2 to 8 carbon atoms, alkynyl having 2 to 8 carbon atoms, a cycloalkyl having 3 to 6 carbon atoms, a cycloalkenyl having 5 to 6 carbon atoms, or phenyl, naphthyl, 2-thienyl, 3-thienyl, 3-pyridyl, the alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, phenyl, naphthyl, 2-thienyl, 3-thienyl and 3-pyridyl being unsubstituted or substituted by hydroxyl, cyano, alkyl having 1 to 3 carbon atoms, alkoxy having 1 to 3 carbon atoms, halogen, phenyl or cyano-substituted phenyl, or a group represented by the formula, -S(O) m R⁶ (in which R⁶ is phenyl or an alkyl having 1 to 3 carbon atoms; m is an integer of 0 to 2), or R⁴ and R⁵ each combine with the other to represent one alkylene group comprising 1 to 6 methylene groups which may be substituted by alkyl having 1 or 2 carbon atoms, phenyl, pyridyl or thienyl; n is an integer of 2 to 6, or a pharmaceutically acceptable salt thereof. A compound as claimed in Claim 1, wherein R¹ is 3-pyridyl. A compound as claimed in Claim 1, wherein R² is phenyl. A compound as claimed in Claim 1, wherein R² is 2-thienyl. A compound as claimed in Claim 1, wherein n is 3 or 4. A compound as claimed in Claim 1, wherein one of R⁴ and R⁵ is hydrogen or methyl. A compound as claimed in Claim 1, wherein one of R⁴ and R⁵ is hydrogen and the other is methyl. A compound as claimed in Claim 1, wherein R⁴ is methyl and R⁵ is methyl. A compound as claimed in Claim 1, wherein R³ is hydrogen. A compound as claimed in Claim 1, wherein R³ is an alkyl group having 1 to 4 carbon atoms. A compound of the formula (I) as claimed in Claim 1, wherein said compound has the formula (I-1): wherein R²´ is a phenyl or thienyl group which may optionally be substituted by an alkoxy having 1 to 4 carbon atoms, an alkyl having 1 to 5 carbon atoms, an halogen, trifluoromethyl or methylenedioxy; one of R⁴´ and R⁵' is hydrogen or an alkyl having 1 to 4 carbon atoms and the other is an alkyl having 1 to 8 carbon atoms or phenyl; and R³ and n are as defined in Claim 1, or a pharmaceutically acceptable salt thereof. A compound as claimed in Claim 1, wherein the compound is 2,2-dimethyl-7-phenyl-7-(3-pyridyl)-6-heptenoic acid. A compound as claimed in Claim 1, wherein the compound is 2,2-dimethyl-7-(3-pyridyl)-7-(2-thienyl)-6-heptenoic acid. A pharmaceutical composition suitable for inhibiting the activity of thromboxane A₂ synthetase in a mammal, which comprises, as an active ingredient, an effective amount of a compound of the formula (I) as defined in Claim 1, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or excipient therefor. A method of producing a compound of the formula (I): wherein R¹ to R⁵ and n are as defined in Claim 1, or a pharmaceutically acceptable salt thereof, which comprises reacting a compound of the formula (II): (wherein R¹, R² and n are as defined above, and X is an halogen atom) with a compound of the formula (III): (wherein R³, R⁴ and R⁵ are as defined above), and, where desired, converting the said compound (I) to its pharmaceutically acceptable salt. A method of producing a compound of the formula (I-2): or a pharmaceutically acceptable salt thereof, wherein R¹ to R³ and n are as defined in Claim 1, and one of R⁷ and R⁸ is an hydrogen atom or an alkyl having 1 to 4 carbon atoms, and the other is an alkyl having 1 to 8 carbon atoms, an alkenyl having 2 to 8 carbon atoms or an alkynyl having 2 to 8 carbon atoms, a cycloalkyl having 3 to 6 carbon atoms, a cycloalkenyl having 5 or 6 carbon atoms, or phenyl, naphthyl, 2-thienyl, 3-thienyl or 3-pyridyl, the alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, phenyl, naphthyl, 2-thienyl, 3-thienyl or 3-pyridyl being unsubstituted or substituted by hydroxyl, cyano, alkyl having 1 to 3 carbon atoms, alkoxy having 1 to 3 carbon atoms, halogen, phenyl or cyano-substituted phenyl, which comprises reacting a compound of the formula (IV): (wherein R¹ and R² are as defined above) with a compound of the formula (V): wherein R³, R⁷, R⁸, and n are as defined above, and X - is an halogen ion, and, where desired converting said compound (I-2) to its pharmaceutically acceptable salt. A method of producing a compound of the formula (I-3): or its pharmaceutically acceptable salt, wherein R¹ to R³ and n are as defined in Claim 1, R⁹ is hydrogen, an alkyl having 1 to 4 carbon atoms, phenylthio or naphthylthio; and R¹⁰ is an alkyl having 1 to 8 carbon atoms, an alkenyl having 2 to 8 carbon atoms or an alkynyl having 2 to 8 carbon atoms; which comprises reacting a compound of the formula (VI): (wherein R¹, R², R³, R⁹ and n are as defined above) with a compound of the formula (VII): (wherein X is an halogen; and R¹⁰ is as defined above), and, where desired, converting said compound (I-3) to its pharmaceutically acceptable salt. A method for producing a compound of the formula (I-5): or its pharmaceutically acceptable salt, wherein R¹ to R³ and n are as defined in Claim 1; R¹³ is hydrogen or an alkyl having 1 to 4 carbon atoms; R¹⁴ and R¹⁵ each represent an alkyl having 1 to 8 carbon atoms, phenyl or naphthyl or combine with the other to represent one alkylene group comprising methylene groups joined in the number of 2 to 6, which comprises reacting a compound of the formula (X): (wherein R¹, R², R³, R¹³ and n are as defined above) with a compound of the formula (XI): (wherein R¹⁴ and R¹⁵ are as defined above), and, when desired, converting said compound (I-5) to its pharmaceutically acceptable salt. A compound of the formula (I) as defined in Claim 1, or a pharmaceutically acceptable salt thereof, for use in the preparation of a medicine for inhibiting the activity of thromboxane A₂ synthetase in a mammal. A method of producing a compound of the formula (I): wherein R¹ to R⁵ and n are as defined in Claim 1, or a pharmaceutically acceptable salt thereof, wherein a compound of the formula (XVI): is reacted with a compound of the formula (XVII): where: W is = CH -(CH₂-) n -X, Y is H, Z¹ is R⁴ and Z² isR⁵; or W is = O, Y is R¹ to R⁵ inclusive and n are as defined above and X is halogen;or wherein a compound of the formula (XVIII): is reacted with a compound of the formula (VII): where in is == CH -(-CH₂-) n -, Z¹ is R⁹ and Z² is H (R¹ to R³ inclusive, n and X being as defined above, R⁹ being hydrogen, an alkyl having 1 to 4 carbon atoms, phenylthio or naphthylthio, and R¹⁰ being an alkyl having 1 to 8 carbon atoms, an alkenyl having 2 to 8 carbon atoms or an alkynyl having 2 to 8 carbon atoms); or wherein a compound of the general formula (XVIII): is reacted with a compound of the formula (IX): where W is -CH (CH₂) n , Z¹ is R¹¹ and Z² is H (R¹ to R³, inclusive and n being as defined above, R¹¹ being H or C₁ ⁻ ₄ alkyl and R¹² being C₁ ⁻ ₄ alkyl or phenyl or naphthyl); or wherein a compound of the general formula (XVIII): is reacted with a compound of the formula (XI): where W is =CH(CH₂) n , Z¹ is R¹³ and Z² is H (R¹ to R³, inclusive, and n being as defined above, R¹³ being hydrogen or an alkyl having 1 to 4 carbon atoms, and R¹⁴ and R¹⁵ each represent an alkyl having 1 to 8 carbon atoms, phenyl or naphthyl or combine with the other to represent one alkylene group comprising methylene groups joined in the number of 2 to 6); or wherein a compound of the general formula (XVIII): is subjected to dehydration (R¹ to R³ and R¹³ to R¹⁵, inclusive, and n being as defined above), and, where, desired said compound (I) is converted to its pharmaceutically acceptable salt. A compound of the formula (I) as claimed in Claim 1, wherein said compound has the formula (I-1) as defined in Claim 11, or a pharmaceutically acceptable salt thereof, for use in the preparation of a medicine for inhibiting the activity of thromborane A₂ synthetase in a mammal. CLAIMS FOR THE FOLLOWING CONTRACTING STATE: AT A method of producing a novel compound of the formula (I): wherein: R¹ is a pyridyl group; R² is a phenyl, thienyl, furyl, naphthyl, benzothienyl or pyridyl group, which is unsubstituted or substituted by an alkoxy having 1 to 4 carbon atoms, an alkyl having 1 to 5 carbon atoms, an halogen, trifluoromethyl, an alkenyl having 2 to 5 carbon atoms or methylenedioxy; R³ is hydrogen, benzyl or an alkyl having 1 to 4 carbon atoms; one of R⁴ and R⁵ is hydrogen or an alkyl having 1 to 4 carbon atoms, and the other is phenyloxy, naphthoxy, alkyl having 1 to 8 carbon atoms, alkenyl having 2 to 8 carbon atoms, alkynyl having 2 to 8 carbon atoms, a cycloalkyl having 3 to 6 carbon atoms, a cycloalkenyl having 5 to 6 carbon atoms, or phenyl, naphthyl, 2-thienyl, 3-thienyl, 3-pyridyl,the alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, phenyl, naphthyl, 2-thienyl, 3-thienyl and 3-pyridyl being unsubstituted or substituted by hydroxyl, cyano, alkyl having 1 to 3 carbon atoms, alkoxy having 1 to 3 carbon atoms, halogen, phenyl or cyano-substituted phenyl, or a group represented by the formula, -S(O)mR⁶ (in which R⁶ is phenyl or an alkyl having 1 to 3 carbon atoms; m is an integer of 0 to 2), or R⁴ and R⁵ each combine with the other to represent one alkylene group comprising 1 to 6 methylene groups which may be substituted by alkyl having 1 or 2 carbon atoms, phenyl, pyridyl or thienyl; n is an integer of 2 to 6, or a pharmaceutically acceptable salt thereof, wherein a compound of the formula (XVI): is reacted with a compound of the formula (XVII): where: W is = CH (CH₂) n X, Y is H, Z¹ is R⁴ and Z² isR⁵; or W is = O, Y is R¹ to R⁵ inclusive and n are as defined above and X is halogen;or wherein a compound of the formula (XVIII): is reacted with a compound of the formula (VII): where W is = CH (CH₂) n , Z¹ is R⁹ and Z² is H (R¹ to R³ inclusive, n and X being as defined above, R⁹ being hydrogen, an alkyl having 1 to 4 carbon atoms, phenylthio or naphthylthio, and R¹⁰ being an alkyl having 1 to 8 carbon atoms, an alkenyl having 2 to 8 carbon atoms or an alkynyl having 2 to 8 carbon atoms); or wherein a compound of the general formula (XVIII): is reacted with a compound of the formula (IX): where W is -CH (CH₂) n , z¹ is R¹¹ and Z² is H (R¹ to R³, inclusive and n being as defined above, R¹¹ being H or C₁ ⁻ ₄ alkyl and R¹² being C₁ ⁻ ₄ alkyl or phenyl or naphthyl); or wherein a compound of the general formula (XVIII): is reacted with a compound of the formula (XI): where W is =CH(CH₂) n , Z¹ is R¹³ and Z² is H (R¹ to R³, inclusive, and n being as defined above, R¹³ being hydrogen or an alkyl having 1 to 4 carbon atoms, and R¹⁴ and R¹⁵ each represent an alkyl having 1 to 8 carbon atoms, phenyl or naphthyl or combine with the other to represent one alkylene group comprising methylene groups joined in the number of 2 to 6); or wherein a compound of the general formula (XVIII): (R¹ to R³ and R¹³ to R¹⁵, inclusive, and n being as defined above), and, where desired, said compound (I) is converted to its pharmaceutically acceptable salt. A method as claimed in Claim 1, wherein R¹ is 3-pyridyl. A compound as claimed in Claim 1, wherein R² is phenyl. A method as claimed in Claim 1, wherein R² is 2-thienyl. A method as claimed in Claim 1, wherein n is 3 or 4. A method as claimed in Claim 1, wherein one of R⁴ and R⁵ is hydrogen or methyl. A method as claimed in Claim 1, wherein one of R⁴ and R⁵ is hydrogen and the other is methyl. A method as claimed in Claim 1, wherein R⁴ is methyl and R⁵ is methyl. A method as claimed in Claim 1, wherein R³ is hydrogen. A method as claimed in Claim 1, wherein R³ is an alkyl group having 1 to 4 carbon atoms. A method as claimed in Claim 1, wherein the novel compound (I) is 2,2-dimethyl-7-phenyl-7-(3-pyridyl)-6-heptenoic acid. A method as claimed in Claim 1, wherein the novel compound (I) is 2,2-dimethyl-7-(3-pyridyl)-7-(2-thienyl)-6-heptenoic acid. A method of producing a novel compound of the formula (I): wherein R¹ to R⁵ and n are as defined in Claim 1, or its pharmaceutically acceptable salt, which comprises reacting a compound of the formula (II): (wherein R¹, R² and n are as defined above, and X is an halogen atom) with a compound of the formula (III): (wherein R³, R⁴ and R⁵ are as defined above), and, where desired, convertin said compound (I) to its pharmaceutically acceptable salt. A method of producing a compound of the formula (I-2): where in R¹ to R³, and n are as defined in Claim 1 and one of R⁷ and R⁸ is an hydrogen atom or an alkyl having 1 to 4 carbon atoms, and the other is an alkyl having 1 to 8 carbon atoms, an alkenyl having 2 to 8 carbon atoms or an alkynyl having 2 to 8 carbon atoms, a cycloalkyl having 3 to 6 carbon atoms, a cycloalkenyl having 5 or 6 carbon atoms, or phenyl, naphthyl, 2-thienyl, 3-thienyl or 3-pyridyl, the alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, phenyl, naphthyl, 2-thienyl, 3-thienyl or 3-pyridyl being unsubstituted or substituted by hydroxyl, cyano, alkyl having 1 to 3 carbon atoms, alkoxy having 1 to 3 carbon atoms, halogen, phenyl or cyano-substituted phenyl, or its pharmaceutically acceptable salt, which comprises reacting a compound of the formula (IV): (wherein R¹ and R² are as defined above) with a compound of the formula (V): wherein R³, R⁷, R⁸, and n are as defined above, and X - is an halogen ion, and, where desired, converting said comound (I-2) to its pharmaceutically accetable salt. A method of producing a compound of the formula (I-3): wherein R¹ to R³' R⁹ and R¹⁰ and n are as defined in Claim 1, or its pharmaceutically acceptable salt, which comprises reacting a compound of the formula (VI): (wherein R¹, R², R³, R⁹ and n are as defined above) with a compound of the formula (VII): (wherein X is an halogen; and R¹⁰ is as defined above), and, where desired, converting said compound (I-3) to its pharmaceutically acceptable salt. A method for producing a compound of the formula (I-5): wherein R¹ to R³, R¹³ to R¹⁵ and n are as defined in Claim 1, or its pharmaceutically acceptable salt which comprises reacting a compound of the formula (X): (wherein R¹, R², R³, R¹³ and n are as defined above) with a compound of formula (XI): (wherein R¹⁴ and R¹⁵ are as defined above), and, where desired, converting said compound (I-5) to its pharmaceutically acceptable salt. A pharmaceutical composition suitable for inhibiting the activity of thromboxane A₂ synthetase in a mammal, which comprises, as an active ingredient, an effective amount of a compound of the formula (I) as defined in Claim 1, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or excipient there for. A compound of the formula (1) as defined in Claim 1, or a pharmaceutically acceptable salt thereof, for use in the preparation of a medicine for inhibiting the activity of thromboxane A₂ synthetase in a mammal. A compound of the formula (I-1): wherein: R², is a phenyl or thienyl group which may optionally be substituted by an alkoxy having 1 to 4 carbon atoms, an alkyl having 1 to 5 carbon atoms, an halogen, trifluoromethyl or methylenedioxy; one of R⁴, and R⁵, is hydrogen or an alkyl having 1 to 4 carbon atoms and the other is an alkyl having 1 to 8 carbon atoms or phenyl; and R³ and n are as defined in Claim 1, or a pharmaceutically acceptable salt thereof, for use in the preparation of a medicine for inhibiting the activity of thromboxane A₂ synthetase in a mammal.

Inventors: NISHIKAWA, KOHEI, TERAO, SHINJI
Applicants: TAKEDA CHEMICAL INDUSTRIES, LTD.
Application year: 1983
Main classification: C07D213
IPC codes: C07D213, C07D409, C07C51, C07D201, C07F9, C07D405