DIBENZ b,e]OXEPIN DERIVATIVE AND PHARMACEUTICAL CONTAINING THE SAME AS ACTIVE INGREDIENT

Abstract: Bibenz(b,e)oxepins of formula (I) and their pharmaceutically acceptable acid addn. salts are new where R1=H or methoxy; R2 is H, methoxy, hydroxy or F; R3 is H or F; R4 is H or F on the 7, 8 or 9-position; Ar is (opt. substd.) phenyl, thienyl or pyridyl. At least two of R1-R4 are H. When R4=F, then R2 and/or R3 is H. When R2=OMe or OH, then R1, R3 and R4 are H. R2 and R3 are not both F. When Ar is thienyl or pyridyl, R2 is H or F, R3 is H or F, and R1=R4=H.

Description: The present invention relates to a novel dibenz[b,e]oxepin derivative, or physiologically acceptable acid addition salt thereof, useful for prevention and treatment of cerebral diseases caused by hypoxia. The brain, different from other organs, exists in a particular environment such that it is immersed in cerebrospinal fluid within rigid bodies such as the skull and pachymenix and is one of the organs showing most active energy metabolism. The oxygen consumption rate of the brain is the highest among all of the organs. Most of the energy required for cranial nerves cells is supplied with oxygen and glucose. Since these energy sources are scarcely stored in the brain, they are always supplied from blood. Therefore, the mechanism for controlling cerebral blood flow in the cerebral blood vessel itself is well developed in order to stably supply the energy source for the brain tissue and to keep the outer environment constant in the cranial nerves cells. However, when the homeostatic mechanism is damaged in the brain by physical oppression such as cerebrovascular disorders, cerebral tumor or cerebral injury, the cranial nerves cells are exposed to a hypoxic condition (cerebral anoxia/cerebral hypoxia) and cannot fulfil the normal function. Such condition of cerebral anoxia increases the production of various toxic active oxygen species. These activated oxygen species peroxidize membrane lipid of the cerebral mitochondria, which results in functional disturbance of the cranial nerves cells and finally a breakdown of the brain cells themselves. This results in a vicious circle such that the functional disturbance of the cranial nerves cells and the breakdown of the brain cells in turn induce severe cerebral anoxia. This is the reason why cerebral anoxia is regarded as a common denominator of most disorders based on cerebral circulartory disturbances [Eur. Neurol., 17 (Supple. 1), 113 (1978)]. Under such circumstances, we have continuously studied to find compounds having an excellent protective effect against cerebral anoxia and preferably with an inhibitory effect on lipid peroxidation of brain mitochondria. We have finally succeeded in finding a novel dibenz[b,e]oxepin derivative to which the present invention is directed. Prior art relevant to the present invention includes US-A-4144337 and ZA-A-85/3053. In the above US-A-4144337, a general range of compounds represented by the following general formula (A) is disclosed. wherein each of R₁ and R₄, which may be the same or different, is hydrogen, halogen of atomic number from 9 to 35, alkyl of 1 to 4 carbon atoms or alkoxy of 1 to 4 carbon atoms, either each of R₂ and R₃ is hydrogen or R₂ and R₃ together are oxygen, either B and D together with the carbon atoms to which they are bound form a benzene ring, or B is sulphur and B and D together with the carbon atoms to which they are bound form a thiophene ring which may be substituted in the position α to the sulphur atom with halogen of atomic number from 9 to 35 or alkyl of 1 to 4 carbon atoms, and when B and D together with the carbon atoms to which they are bound form a benzene ring, A is oxygen, sulphur, -CH₂-O- or -CH₂-S- in either orientation, or a group of formula wherein each of R₅ and R₆, which may be the same or different, is alkyl of 1 to 4 carbon atoms, or when B is sulphur and B and D together with the carbon atoms to which they are bound form a substituted or unsubstituted thiophene ring, A is a group of formula wherein each of R₇ and R₈, which may be the same or different, is hydrogen or alkyl of 1 to 4 carbon atoms and either each of E and F is hydrogen or E and F together form a bond. Although the above general formula (A) includes dibenz[b,e]oxepin derivatives, there is no specific disclosure of such a compound. Moreover, the compounds which are specifically disclosed therein are said to have psychostimulant and vigilance-increasing effects, these activities being completely different from those of the compounds of the present invention. The above ZA-A-85/3053 discloses a general range of compounds represented by the following general formula (B). wherein X is hydrogen, halogen, lower alkoxy, lower alkylthio, lower alkylsulfonyl or trifluoromethyl, R is hydrogen, lower alkyl cinnamyl, lower alkoxycinnamyl, cinnamoyl, lower alkoxycinnamoyl, lower hydroxyalkyl or carbalkoxy, Z is a saturated or unsaturated 2-3 atom chain in which no more than one atom of the chain is other than carbon and which is optionally substituted with 1 to 2 halogen atoms. The above general formula (B) includes dibenz[b,e]oxepin derivatives of which one is specifically disclosed, namely 1-(2-isopropoxy-6,11-dihydrobenz[b,e]oxepin-11-yl)-4-(n-butyl) piperazine. The compounds which are specifically disclosed are said to be effective as inhibitors of calcium induced-contraction of vascular smooth muscle and therefore useful for treatment of cardiovascular disorders as calcium entry blockers. However, this effect and use are entirely different from those of the compounds of the present invention. Thus, the present invention provides, according to various aspects, (1) a compound represented by the formula (1) or a physiologically acceptable acid addition salt thereof; (2) a compound of the formula (I) or a physiologically acceptable acid addition salt thereof for use as a pharmaceutical, especially for prevention and/or treatment of cerebral disease caused by hypoxia; (3) a pharmaceutical composition comprising a compound of the formula (I) or a physiologically acceptable acid addition salt thereof and a pharmaceutically acceptable carrier, which pharmaceutical composition may be in the form of tablets or capsules; (4) use of a compound of the formula (I) or a physiologically acceptable acid addition salt thereof for the manufacture of a composition for the prevention and/or treatment of cerebral disease caused by hypoxia; and (5) a process for preparing a compound represented by the formula (I) or a physiologically acceptable acid addition salt thereof which comprises (a) reacting a compound represented by the formula (II) wherein Y is a reactive ester residue of an alcohol, with a compound represented by the formula (III) or (b) reacting a compound represented by the formula (IV) with a compound represented by the formula (V) wherein Z is a reactive ester residue of an alcohol, and (c) optionally treating the obtained free base with an acid to convert into the corresponding acid addition salt or treating the obtained acid addition salt with a base to convert into the corresponding free base. The physiologically acceptable acid addition salts of the compounds of the present invention include, for example, inorganic acid salts such as hydrochloride, hydrobromide, hydroiodide, sulfate and phosphate, and organic acid salts such as oxalate, maleate, fumarate, lactate, malate, citrate, tartrate, benzoate and methanesulfonate. The compound of the formula (I) and the acid addition salts thereof may exist in she form of hydrate or solvate and these hydrates and solvates are also compounds within the present invention. Since the compound of the formula (I) has one asymmetric carbon atom and the substituent at the 4-position of the piperazine has one double bond, the compounds of the present invention can exist in the form of an optical isomer or a stereoisomer. These isomers and any mixture thereof are also compounds within the present invention. Referring again to the prior art it can be seen that the compounds of the present invention come within both of the general formulae (A) and (B) disclosed respectively in US-A-4144337 and ZA-A-85/3053. However, the present invention provides compounds which are not specifically disclosed in either of these documents and provides a pharmaceutical application entirely different from those described in these respective documents. Compounds of the present invention namely, 11-(4-Cinnamyl-1-piperazinyl)-3-fluoro-6,11-dihydrodibenz[b,e]oxepin and physiologically acceptable salts thereof, may have an excellent protective effect against cerebral anoxia, and may also have an inhibitory effect on lipid peroxidation of brain mitochondria and an anti-convulsant activity. In the compounds (I) of the present invention, the conformation with respect to the double bond is preferably a trans form, that is E form. The pharmacological activities of a compound of the present invention are illustrated by the following pharmacological tests on a compound of the present invention (No. 1), the compounds A and B which are outside the present invention (see Reference Examples 2 and 3 described hereinafter), and flunarizine hydrochloride which is a commercially available drug useful for the treatment of cerebrovascular disorders. Experiment 1 Protective Effect Against Cerebral Anoxia (1) Prolonging effect of the persistence time of gasping movements in complete ischemia The test was conducted in accordance with the procedure of Wauquier et al. [Japan J. Pharmacol., 38 , 1 (1985)], employing five ddY male mice weighing 20-24 g in each group. Test compounds were suspended in 0.5% tragacanth solution and then a fixed amount of the suspension was orally administered to mice in an amount of 0.1 ml/10 g body weight, while the same amount of 0.5% tragacanth solution was orally administered to control group. Two hours after the administration of the test compounds, the necks of mice were cut with scissors for decapitation. The persistence of gasping movements of isolated heads was measured and minimal effective dose was determined by statistically comparing with the data in control group. The results are shown in Table 1. As shown in Table 1, the activity of the compound of the present invention (No. 1) is much more potent than flunarizine hydrochloride. In contrast, the compounds A and B outside the present invention have lower activities. (2) Prolonging effect on the time to death by hypoxia in mice Five STD-ddY male mice (weighing 20-24 g) were employed in each group. A fixed amount of test compound was suspended in 0.5% tragacanth solution and the suspension was orally administered to mice in an amount of 0.1 ml/10 g body weight. Two hours after the administration, each mouse was placed in a 2.5 liter plastic chamber and a mixed gas comprising 4% oxygen and 96% nitrogen was passed through the chamber at a rate of 4 liter/min. The time till the death (respiratory cessation) of mice was measured. To a control group, a 0.5% tragacanth solution without a test compound was orally administered. The results are shown in Table 2. As shown in Table 2, the prolonging effect under hypoxic condition of the compound 1 of the present invention is clearly more excellent than that of flunarizine hydrochloride. Experiment 2 Inhibitory Effect on Lipid Peroxidation of Brain Mitochondria This test was conducted in accordance with the procedures Kubo et al. [Arch. int. Pharmacodyn., 272 , 283 (1984)]. Brain mitochondria of rat were incubated in 25 mM Tris-HCl buffer solution at 37°C for 30 minutes in the presence of Fe⁺⁺ ion (25µM) and ascorbic acid (50µM), and the produced peroxidized lipid was measured by the thiobarbituric acid method. A concentration of the test compounds to inhibit the production of peroxidized lipid by 50% (IC₅₀) was calculated. The results are shown in Table 3. Experiment 3 Anti-convulsant Activity Three ddY male mice weighing 20-24 g were employed in each group. Test compounds suspended in a 0.5% tragacanth solution were orally administered to mice at a dose of 100mg/kg in an amount of 0.1 ml/10 g body weight. The same amount of 0.5% tragacanth solution was orally administered to a control group. Two hours after the administration of the test compounds, the anti-convulsant activity was measured in accordance with the procedure of Swinyard (Mercier, J., Ed., "Anticonvulsant Drugs", P. 47-65, Pargamon Press, New York, 1973). The results are shown in Table 4. Experiment 4 Acute Toxicity Five ddY male mice weighing 20 - 24 g were employed in each group. The compound 1 of the present invention suspended in a 0.5% tragacanth solution was orally administered to mice at a dose of 500 mg/kg in an amount of 0.1 ml/10 g body weight. After the administration, the occurrence of death has been observed for seven days. The result showed no death of the animal. The process for preparing the compounds of the present invention is illustrated. The compound (I) of the present invention or the physiologically acceptable acid addition salts thereof can be prepared by either the following process (a) or (b). Process (a) The compounds (I) of the present invention can easily be prepared by reacting a compound having the formula (II): wherein Y is a reactive ester residue of an alcohol, with a compound having the formula (III) The reactive ester residue of an alcohol represented by Y in the general formula (II) includes halogen atoms such as chlorine or bromine, lower alkylsulfonyloxy groups such as methanesulfonyloxy or ethanesulfonyloxy, arylsulfonyloxy groups such as benzene sulfonyloxy, p-toluenesulfonyloxy or m-nitro benzene sulfonyloxy. The reaction between the compound of the formula (II) and the compound of the formula (III) is carried out in the absence of a solvent or in the presence of a suitable solvent. Examples of the solvent are aromatic hydrocarbons such as benzene, toluene and xylene, halogenated hydrocarbons such as methylene chloride and chloroform, ketones such as methyl ethyl ketone, ethers such as tetrahydrofuran and dioxane, acetonitrile and dimethylformamide. These solvents may be employed alone or in a mixture of two or more thereof. The reaction is preferably carried out in the presence of a base. Examples of the base are organic bases such as triethylamine, tributylamine, diisopropylethylamine and N-methylmorpholine. An excess amount of the compound of the general formula (III) also acts as the base. The reaction temperature is usually from about 0° to about 80°C. Process (b) The compounds (I) of the present invention can easily be prepared by reacting a compound represented by the following formula (IV) with a compound represented by the following formula (V) wherein Z is a reactive ester residue of an alcohol. In the formula (V), the reactive ester residue of an alcohol represented by Z includes the same groups or atoms as mentioned in the above process (a). The reaction between the compound of the formula (IV) and the compound of the formula (V) is carried out in the absence of a solvent or in the presence of the same solvent as mentioned in the process (a) and preferably in the presence of a base. The base includes alkali hydrogen carbonates such as sodium hydrogen carbonate and potassium hydrogen carbonate, and alkali carbonates such as sodium carbonate and potassium carbonate in addition to the organic base mentioned in the process (a). The reaction temperature is usually from about 0° to about 160°C. When the compound wherein Z in the general formula (V) is chlorine or bromine is employed, the addition of alkali metal iodides such as sodium iodide and potassium iodide promotes the reaction more smoothly. The compounds of the formula (I) of the present invention formed by the above processes are isolated and purified by the conventional procedure such as chromatography, recrystallization or reprecipitation. The compounds of the formula (I) are obtained in the form of a free base or an acid addition salt, depending on the selection of the starting compound, the reaction condition or the treating condition. The acid addition salt can be converted into the free base by a conventional procedure, for example, by treating the salt with a base such as an alkali carbonate. On the other hand, the free base can be converted into the acid addition salt by treating the base with various acids in accordance with the conventional process. The starting compounds (II) and (IV) can be prepared by the processes of the following Reference Examples or in a similar manner. Since the thus obtained compounds (I) of the present invention or the physiologically acceptable acid addition salts thereof may have an excellent protective effect against cerebral anoxia and also an inhibitory effect on lipid peroxidation of mitochondial memberane of brain and an anti-convulsant activity, they are especially useful for the protection and/or the treatment of cerebral diseases caused by hypoxia, such as cerebrovascular disorders (e.g. cerebral infraction, cerrebral hemorrhage and cerebral arteriosclerosis), cerebral tumor and cerebral injury. The compounds of the formula (I) and the physioligically acceptable acid addition salts thereof may be administered by means of any of oral, parenteral or intrarectal administration, preferably by oral administration. Although the dose is varied depending on the kind of compound, the administration route, the conditions and the age of the patients and the like, it is usually 0.005 - 20 mg/kg/day. The compounds of the formula (I) or the acid addition salts thereof are usually administered in the form of pharmaceutical preparations prepared by mixing with a pharmaceutical carrier. The pharmaceutical carrier includes substances which are commonly used in the pharmaceutical field and do not react with the compounds of the formula (I) or the acid addition salts thereof. Examples thereof are, lactose, glucose, mannitol, dextrin, cyclodextrin, starch, sucrose, magnesium metasilicate aluminate, synthetic aluminium silicate, crystalline cellulose, sodium carboxymethylcellulose, calcium carboxymethylcellulose, ion exchange resin, methylcellulose, gelatin, gum arabic, Pullulan, hydroxypropyl cellulose, low-substituted hydroxypropyl cellulose, hydroxypropyl methyl cellulose, polyvinylpyrrolidone, polyvinyl alcohol, light silicic anhydride, magnesium stearate, talc, tragacanth, bentonite, bee gum, carboxyvinyl polymer, titanium oxide, sorbitan fatty acid esters, sodium laurylsulfate, glycerin, glycerin fatty acid esters, purified lanolin, glycero-gelatin, polysorbate, macrogol, vegetable oil, wax, propylene glycol and water. Dosage forms include tablets, capsules, granules, powders, syrups, suspensions, injections and suppositories These pharmaceutical preparations are prepared in accordance with conventional procedures. Liquid preparations may be dissolved or suspended in water or other suitable mediums when used. Tablets and granules may be coated by the known method. These pharmaceutical preparations can contain not less than 0.5%, preferably from 1 - 70% of the compound of the formula (I) or the physiologically acceptable acid addition salt thereof. These pharmaceutical preparations may contain other components which are valuable in the treatment. The present invention is illustrated in more detail by the following Reference Examples and Examples. The identification of the compound was carried out by elemental analysis, mass spectrum, IR spectrum and NMR spectrum. The conformation relating to the double bond is an E form (trans form) unless specified otherwise. Reference Example 1 Preparation of 11-chloro-3-fluoro-6,11-dihydrodibenz[b,e]oxepin: To a solution of 5.2 g of sodium metal in 300 ml of ethanol is added 25 g of 3-fluorophenol. The solvent is distilled off under reduced pressure. To the residue is added 25 g of phthalide and the mixture is stirred at 200°C for 1 hour with heating. After cooling to 100°C, 500 ml of water is added to dissolve and thereto 10% hydrochloric acid is added under ice cooling to make the solution acidic to precipitate a crystalline product, which is filtered, washed with water and dried to give 42 g of 2-[(3-fluorophenyloxy)methyl]benzoic acid. Mass spectrum m/z: 246(M+). To 250 g of phosphorus pentoxide is slowly added 160 ml of ethanol at room temperature. The mixture is further stirred with heating at 100°C for 1 hour. Thereto 42 g of 2-[(3-fluorophenyloxy)methyl]benzoic acid is added and the mixture is refluxed with heating at 100°C for 1 hour. After cooling to room temperature, 500 ml of water is added. After extraction with toluene, washing successively with saturated sodium hydrogen carbonate, water and a saturated saline solution and drying over magnesium sulfate, the solvent is distilled off under reduced pressure to give 31 g of 3-fluoro-6,11-dihydrodibenz[b,e]oxepin-11-one (oil). Mass spectrum m/z: 228(M+). To a solution of 2.0 g of 3-fluoro-6,11-dihydrodibenz[b,e]oxepin-11-one in 20 ml of methanol is added 0.5 g of sodium borohydride with ice-cooling and then the mixture is stirred at the same temperature for 1 hour. The reaction mixture is poured into water and the resultant is extracted with toluene. The extract is washed with water and then dried over magnesium sulfate. Toluene is distilled off to give 1.9 g of 3-fluoro-6,11-dihydrodibenz[b,e]oxepin-11-ol (crystals). Mass spectrum m/z: 230(M+). To a solution of 1.5 g of 3-fluoro-6,11-dihydrodibenz[b,e]oxepin-11-ol in 20 ml of methylene chloride is added dropwise a solution of 1.6 g of thionyl chloride in 10 ml of methylene chloride under ice cooling over 30 minutes and then the mixture is stirred at room temperature for 1 hour. The reaction mixture is concentrated at room temperature under reduced pressure to give 1.5 g of 11-chloro-3-fluoro-6,11-dihydrodibenz[b,e]oxepin (oil). Mass spectrum m/z: 248(M+) Example 1 Preparation of 11-(4-cinnamyl-1-piperazinyl)-3-fluoro-6,11-dihydrodibenz[b,e]oxepin: (a) To a solution of 4.0 g of 1-cinnamylpiperazine in 20 ml of chloroform is added a solution of 2.0 g of 11-choloro-3-fluoro-6,11-dihydrodibenz[b,e]oxepin, which is prepared in Reference Example 1, in 10 ml of chloroform under ice cooling and then the mixture is stirred at room temperature for 2 hours. The reaction mixture is poured into 5% aqueous sodium hydrogen carbonate and the mixture is extracted with chloroform. After the extract is washed with water, chloroform is distilled off. The residue is subjected to silica-gel chromatography and eluted with chloroform to give 1.5 g of the desired compound as an oil. Mass spectrum m/z: 414(M+). (b) To a solution of 1.4 g of the above free base in 10 ml of ethanol is added 0.6 g of oxalic acid to dissolve with heating and then the solution is cooled. Precipitated crystals are collected by filtration and recrystallised from ethanol to give the desired oxalate. Melting point 204-207°C (dec.). (c) To a solution of 1.4 g of the above free base in 10 ml of ethanol is added 0.8 g of maleic acid to dissolve and then diethyl ether is added. Precipitated crystals are collected by filtration and recrystallised from ethanol-diethyl ether to give 3/2 maleate monohydrate of the desired compound (compound 1). Melting point 133-135°C. (d) (Z)-1-cinnamylpiperazine is employed in place of 1-cinnamylpiperazine (E form) in the above (a) and the reaction and the treatment are conducted in the same manner as in the procedure (a) to give (Z)-11-(4-cinnamyl-1-piperazinyl)-3-fluoro-6,11-dihydrodibenz[b,e]oxepin as an oil. Mass spectrum m/z: 414(M+). This free base is treated by the above procedure (c) and recrystallised from ethanol-diethyl ether to give corresponding 2 maleate. Melting point 121-124°C. Reference Example 2 Preparation of 11-[4-(3'-methoxycinnamyl)-1-piperazinyl-3-fluoro-6,11-dihydrodibenz[b,e]oxepin (compound A): Starting from 11-chloro-3-fluoro-6,11-dihydrodibenz[b,e]oxepin, prepared in Reference Example 1, and (1-(3'-methoxycinnamyl)-piperazine, the 2 maleate of the desired compound is produced in the same manner as in Example 1. Melting point 136-140°C (recrystallised from ethanol-diethyl ether). Reference Example 3 Preparation of 11-(4-cinnamyl-1-piperazinyl)-3-methyl-6,11-dihydrodibenz[b,e]oxepin (compound B): Starting from 11-chloro-3-methyl-6,11-dihydrodibenz[b,e]oxepin, which is prepared from 3-methylphenol and phthalide in the same manner as in Reference Example 1, and 1-cinnamylpiperazine, the 2-oxalate·1/2 hydrate of the desired compound is produced in the same manner as in Example 1. Melting point 195-200°C (recrystallized from ethanol-diethyl ether). Example 2 Preparation of tablets: 11-(4-Cinnamyl-1-piperazinyl)-3-fluoro-6,11-dihydrodibenz[b,e]oxepin·3/2 maleate·1 hydrate (compound 1) 5 g Corn starch 33 g Lactose 75 g Crystalline cellulose 30 g Hydroxypropyl cellulose 5 g Light silicic anhydride 1 g Magnesium stearate 1 g In accordance with the conventional procedure, the above ingredients are mixed and granulated and compressed to prepare 1000 tablet cores (150 mg in each). These are coated in accordance with the conventional procedure, employing hydroxypropyl methyl cellulose, talc, titanium oxide and sorbitan monooleate to prepare film-coated tablets. Example 3 Preparation of capsules: 11-(4-Cinnamyl-1-piperazinyl)-3-fluoro-6,11-dihydrodibenz[b,e]oxepin·3/2 maleate·1 hydrate (compound 1) 10 g Corn starch 44 g Lactose 20 g Crystalline cellulose 25 g Talc 0.5 g Magnesium stearate 0.5 g In accordance with the conventional procedure, the above ingredients are mixed and granulated and filled in 1000 capsules to prepare capsules (100 mg in each). As mentioned above, the compounds of the formula (I) of the present invention or the physiologically acceptable acid addition salts thereof may have an excellent protective effect against cerebral anoxia and may also have an inhibitory effect on lipid peroxidation of mitochondrial membrane of brain and an anti-convulsant activity and are useful as agents for the treatment of cerebral diseases caused by hypoxia in mammals including human.

Claims: A compound represented by the formula (I) or a physiologically acceptable acid addition salt thereof. A compound according to claim 1 or a physiologically acceptable acid addition salt thereof, for use as a pharmaceutical. A compound according to claim 2, for prevention and/or treatment of cerebral disease caused by hypoxia. A pharmaceutical composition comprising a compound according to claim 1 or a physiologically acceptable acid addition salt thereof, and a pharmaceutically acceptable carrier. A composition according to claim 4, which is in the form of tablets or capsules. Use of a compound or a physiologically acceptable acid addition salt thereof according to claim 1, for the manufacture of a pharmaceutical composition. Use according to claim 6, for the manufacture of a composition for the prevention and/or treatment of cerebral disease caused by hypoxia. A process for preparing a compound represented by the formula (I) or a physiologically acceptable acid addition salt thereof which comprises (a) reacting a compound represented by the formula (II) wherein Y is a reactive ester residue of an alcohol, with a compound represented by the formula (III) or (b) reacting a compound represented by the formula (IV) with a compound represened by the formula (V) wherein Z is a reactive ester residue of an alcohol, and (c) optionally treating the obtained free base with an acid to convert into the corresponding acid addition salt or treating the obtained acid addition salt with a base to convert into the corresponding free base.

Inventors: KUROKAWA MIKIO, MASUDA YOSHINOBU, NARUTO SHUNSUKE, SATO FIMINORI, UNO HITOSHI, KUROKAWA, MIKIO, MASUDA, YOSHINOBU, NARUTO, SHUNSUKE, SATO, FIMINORI, UNO, HITOSHI
Applicants: DAINIPPON PHARMACEUTICAL CO, DAINIPPON PHARMACEUTICAL CO., LTD.
Application year: 1987
Main classification: C07D313
IPC codes: C07D313, C07D409, C07D401