SUBSTITUTED ISOQUINOLINE DERIVATIVES AND ANTI-ULCER AGENTS

Abstract: A compound of the formula : (wherein R is hydrogen, hydroxy, methoxy, acetoxy, acetoxymethyl or trifluoromethyl; R¹, R², R³ and R⁴ each is hydrogen, hydroxy, optionally substi­ tuted C₁-C₅ alkoxy, acetoxy, propynyloxy, allyloxy or benzyloxy; or R² and R³ taken together form methylenedioxy; R⁵ is hydrogen, hydroxymethyl, C₂-C₄ alkoxycarbonyl, C₂-C₅ acyl­ oxymethyl or phthalidyl; and n is 0 or 1 except for the case in which R is methoxy and R¹, R², R³, R⁴ and R⁵ each is hydrogen) or its pharmaceutically acceptable acid addition salt, being useful as anti-ulcer agents is provided through several routes.

Description: The present invention relates to substituted isoquinoline derivatives. More particularly, this invention is directed to substituted isoquinoline derivatives which have been found to be particularly effective in the treatment of ulcer, to their production, to their use and to pharmaceutical formulations containing the compounds. 2-[(1-Isoquinolylmethyl)sulfinyl]-5-methoxybenzimidazole is hitherto known as this kind of compound, but this compound is defectively somewhat low in the acid secretion-suppressing action (Brit. Pat. No. 2134523-A). The inventors of the present inventions have been studying on anti-ulcer agents of benzimidazole family. According to the present invention there is provided a substituted isoquinoline derivative of the formula: (wherein R is hydrogen, hydroxy, methoxy, acetoxy, acetoxymethyl or trifluoromethyl; R¹, R², R³ and R⁴ each is hydrogen, hydroxy, optionally substitu­ ted C₁-C₅ alkoxy, acetoxy, propynyloxy, allyloxy or benzyloxy; or R² and R³ taken together form methylenedioxy; R⁵ is hydrogen, hydroxymethyl, C₂-C₄ alkoxycarbonyl, C₂-C₅ acyl­ oxymethyl or phthalidyl; and n is 0 or 1 except for the case in which R is methoxy and R¹, R², R³, R⁴ and R⁵ each is hydrogen) or its pharmaceutically acceptable acid addition salt. The compounds of the present invention have an excellent anti-ulcer activity. Accordingly the invention also provides a pharmaceutical composition comprising as an active ingredient 0.1 to 95 % by weight of at least a compound of the formula (I) associated with at least one carrier, diluent and/or excipient therefor. This invention also provides the compounds of formula (I) for use in a method of treating a patient suffering from ulcers which com­ prises administering to the patient a pharmacologically effective amount of a compound of the formula (I). This invention further provides a process for preparing a compound of the formula (I) which comprises: a) reacting a compound of the formula: (wherein R is as defined above) with a compound of the formula: (wherein R¹, R², R³ and R⁴ each has the same meaning as defined above) to give a compound of the formula: (wherein R, R¹, R², R³ and R⁴ each has the same meaning as defined above), b) subjecting the compound (Ia) to (i) hydroxymethylation followed by O-acylation or (ii) N-substitution with halomethyl alkanoate or 3-halophthalide to give a compound of the formula: (wherein R, R¹, R², R³, R⁴ and R⁵ each has the same meaning as defined above), c) oxidizing the compound (Ia) to give a compound of the formula: (wherein R, R¹, R², R³ and R⁴ each has the same meaning as defined above), d) oxidizing the compound (Ib) to give a compound of the formula: (wherein R, R¹, R², R³ and R⁴ each has the same meaning as defined above and R⁵ is C₂-C₄ alkoxycarbonyl, C₂-C₅ acyloxymethyl or phthalidyl), or e) subjecting the compound (Ic) to N-substitution with halomethyl alkanoate or 3-halophthalide to give a compound of the formula: (wherein R, R¹, R², R³ and R⁴ each has the same meaning as defined above and R⁵ is C₂-C₅ acyloxymethyl or phthalidyl). The term "C₁-C₅ alkoxy" represents methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, iso-butoxy, sec-butoxy, tert-­ butoxy, n-pentyloxyl, iso-pentyloxy, sec-pentyloxy, neo-pentyloxy, or tert-pentyloxy. The optional substituent on the C₁-C₅ alkoxy includes C₃-C₆ cycloalkyl such as cyclopropyl, cyclopentyl or cyclohexyl and one or more halogens such as fluorine, chlorine or bromine. The term "C₂-C₄ alkoxycarbonyl" includes ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl and isobutoxycarbonyl. The term "C₂-C₅ acyloxymethyl" includes alkanoyloxymethyl (e.g. acetoxymethyl, propionyloxymethyl, butyryloxymethyl, piva­ loyloxymethyl, valeryloxymethyl) and alkoxycarbonyloxymethyl (e.g. ethoxycarbonyloxymethyl, propoxycarbonyloxymethyl, butoxycarbonyl­ oxymethyl). The process for preparing the compound (I) is shown by the scheme as follows: (wherein R, R¹, R², R³, R⁴ and R⁵ each has the same meaning as defined above). Step I Method A In this step, the compound (II) is allowed to react with the compound (III) in the presence of a base in an appropriate solvent, whereby the objective compound (Ia) is obtained. As the base used in this reaction, an inorganic base (e.g. K₂CO₃, Na₂CO₃, NaOH, NaHCO₃, etc.) and an organic base (e.g. Et₃N, pyridine, etc.) are exemplified. As the solvent MeOH, EtOH, benzene, CHCl₃, carbon tetrachloride, dimethyl sulfoxide, tetrahydrofuran, dimethylform­ amide and water are exemplified. The reaction was performed at 0 - 120 °C, preferably 15 - 50 °C. Method B In this step, the compound (II) is allowed to react with the compound (III) to give the objective compound (Ia) as in Method A. This reaction is performed by using the said base and solvent at 15 - 120 °C, but it is preferable to use the KOH - EtOH system with heating up to a reflux temperature of the solvent. In this reaction the aromatization of dihydroquinoline ring by dehydrogenation brings about at the same time, whereby the objective compound (Ia) is obtained in a good yield. Step II Method A The compound (Ia) obtained in the former step is allowed to react with formaldehyde in a solvent such as acetonitrile or dimethylformamide to give the compound (Ib) (R⁵ = CH₂OH). This hydroxymethylation is performed at 15 - 100 °C, preferably at 50 - 80 °C. Then the compound (Ib) (R⁵ = CH₂OH) is subjected to acy­ lation to produce the O-acylate (Ib) containing R⁵ moiety. This reaction is performed by using an acid anhydride (e.g. acetic anhydride, butyric anhydride, etc.) or lower alkyl haloformate (e.g. ethyl chloroformate, n-propyl chloroformate, etc.). If necessary, it can be carried out in a conventional manner for acylation in the presence of a solvent and/or a base as illustrated above. The reaction is performed at 15 to 120 °C, preferably 50 to 100°C. In the case of using lower alkyl haloformate as an acy­ lating agent, eventually the N-alkoxycarbonyl compound (Ib) (R⁵ = alkoxycarbonyl) is produced together with the N-acyloxymethyl compound (Ib) (R⁵ = alkoxycarbonyloxymethyl). Method B Alternatively, the compound (Ia) is subjected to N-sub­ stitution to give the N-substituted compound (Ib) (R⁵ = alkanoyloxy­ methyl or phthalidyl). The compound (Ia) is allowed to react with halomethyl alkanoate (e.g. chloromethyl pivalate, bromomethyl butyrate, chloromethyl acetate, etc.) or 3-halophthalide (e.g. 3-­ chlorophthalide, 3-bromophthalide). The reaction with halomethyl alkanoate is performed in the presence of a base such as alkali metal hydride such as sodium hydride or potassium hydride in a solvent such as dimethyldform­ amide, hexamethylphosphoramide or the like at 15 to 100 °C, pre­ ferably room temperature. Further the reaction with 3-halophthalide is performed in the presence of a base such as sodium hydride or triethylamine in a solvent such as dimethylformamide, hexamethylphosphoramide or the like at 15 to 120 °C, preferably 50 to 80 °C. Step III The compound (Ia) is oxidized with a peracid to give the sulfinyl compound (Ic). The oxidation is performed with appropriate oxidizing agents (e. g. hydrogen peroxide, perbenzoic acid, m-chloroperbenzoic acid or the like) in a solvent such as chlcoroform, 1,2-dichloroethane, carbon tetrachloride, dimethyl­ formamide, acetic acid or the like at a temperature from -100 to 0 °C, preferably -30 to -5 °C, or at room temperature (e. g. 15 to 25 °C). After finishing the reaction, the mixture is treated with aqueous sodium bisulfite for decomposing a certain amount of the peracid remaining there in a conventional manner. Step IV The compound (Ib) is oxidized with a peracid to give the sulfinyl compound (Id). This oxidation is performed under the same conditions as in Step III. Step V The compound (Ic) is subjected to N-substitution with halomethyl alkanoate or 3-halophthalide to give the N-substitution compound (Id). The N-substitution is performed under the same conditions as in Method B of Step II. The starting material (III) and (IV), for example, can be manufactured by the following process. The compound (I) can be converted into its pharmaceuti­ cally acceptable acid addition salts. Such acids illustratively include an inorganic acid such as hydrochloric acid, sulfuric acid, phosphoric acid or nitric acid and organic acid such as acetic acid, maleic acid, malic acid, citric acid, lactic acid, succinic acid or methanesulfonic acid. The compounds (I) can be adminstered enterally or parenterally to human being. They can be formulated as tablets, capsules, pills, granules, injections, suppositories and syrups according to customary pharmaceutical practice. As pharma­ ceutically acceptable carriers, diluents or excipients, there are examplified lactose, sucrose, wheat starch, potato starch, magnesium stearate, gelatin, methyl cellulose, agar, water and the like. As necessary, appropriate stabilizers, emulsifiers, spreaders, buffers and other pharmaceutical adjuvants can be added. Appropriate daily dosage of the compound (I) is 0.1 to 500 mg in oral route and 0.1 to 300 mg in injection. The present invention will be explained in more detail by the following Examples, Reference Examples and Formulations. The abbreviations used in Examples, Reference Examples and Tables have the following meanings. Me : methyl Ph : phenyl EtOH : ethanol AcOH : acetic acid CH₃CN : acetonitrile Et₂O : ethylether CH₂Cl₂ : dichloromethane CHCl₃ : chloroform THF : tetrahydrofuran DMF : dimethylformamide POCl₃ : phosphorus oxychloride LiAlH₄ : lithium alminium hydride MeO : methoxy EtO : ethoxy O-Al : allyloxy O-Bz : benzyloxy O-i-Pro : isopropyloxy (d) : decomposition Et : ethyl MeOH : methanol KOH : potassium hydroxide NaOH : sodium hydroxide KCN : potassium cyanide AcOEt : ethyl acetate HCHO : formaldehyde Et₃N : triethylamine NaH : sodium hydride Example 1 2-[(6,7-Dimethoxyisoquinolin-1-yl)methylthio]benz­ imidazole (Ia- 1) (1) To 306.3 mg of 6, 7-dimethoxyisoquinolin-1-ylmethanol (1.397 mmol) were added 20 ml of dry CH₂Cl₂ and 665 mg of thionyl chloride (5.95 mmol) and the mixture was stirred for 2 hours at room temperature. The reaction solution was concentrated to give 490 mg of 1-chloro-(6,7-dimethoxyisoquinolin-1-yl)­ methane (III-1) as brown crystals. (2) To the above product were added 220-3 mg of 2-mercapto­ benzimidazole (1.467 mmol), 1.16 g of potassium carbonate (8.38 mmol) and 10 ml of dry dimethylformamide, and the mixture was stirred for 17 hours at room temperature. Dimethylformamide was distilled off under reduced pressure. Water was added to the residue and the mixture was extracted with CH₂Cl₂. The organic layer was dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was subjected to silica gel column chromatography for purification. The extract was crysta­ llized from CH₂Cl₂ - cyclohexane to give 369.1 mg of the objective compound 2-[(6,7-dimethoxy-isoquinolin-1-yl)methylthio]benzimida­ zole (Ia - 1) (yield : 75 .2 %) as crystals. m.p. : 183.5 - 185.5 °C (d) Anal Calcd. (%) for C₁₉H₁₇N₃O₂S : C, 64.74; H, 4.88; N, 11.96; S, 9.12 Found (%) : C, 64.82; H, 4.77; N, 11.86; S, 9.15 Example 2 - 6 wherein R¹, R², R³, R⁴ and R has the same meaning as defined above). In the same method as in Example 1, the reaction was performed under the reaction conditions as defined in Table 1, whereby the objective compounds (Ia) were obtained. Example 7 2-{[6-Methoxy-7-(2,2,2-trifluoroethoxy)isoquinolin-1-yl]­ methylthio}benzimidazole (Ia- 7) To a solution of 514.8 mg of 86 % KOH (7.87 mmol) in 20 ml of 99 % EtOH were added 434.1 mg of 2-mercaptobenzimidazole (II-1) (2.89 mmol) and 900.1 mg of 1-dichloromethyl-6-methoxy-7-­ (2,2,2-trifluoroethoxy)-3,4-dihydroisoquinoline (IV-1) (2.63 mmol) in order. After stirring for 30 min. at room temperature, the mixture was refluxed for 3 hr. and concentrated under reduced pressure. The residue was mixed with water and extracted with CHCl₃. The objective compound existing as an insoluble material was filtered and combined with CHCl₃ extract to give 722.5 mg of the crude product. It was dispersed in 15 ml of CH₂Cl₂, filtered and washed with CH₂Cl₂ to give 666.5 mg of the titled compound 2-­ {[6-methoxy-7-(2,2,2-trifluoroethoxy)isoquinolin-1-yl]methylthio}­ benzimidazole (Ia -7) (Yield : 60.4 %). m.p. : 232 - 234 °C (d) Anal Calcd. (%) for C₂₀H₁₆N₃O₂SF₃ : C, 57.27; H, 3.84; N, 10.02; S, 7.64; F, 13.59 Found (%) : C, 56.98; H, 3.92; N, 9.97; S, 7.77; F, 13.36 Example 8 - 21 (wherein R¹, R², R³ and R⁴ have the same meaning as defined above). In the same method as in Example 7, the reaction was performed under the reaction conditions as defined in Table 2, whereby the objective compounds (Ia) were obtained. Example 22 1-Hydroxymethyl-2-[(6,7-dimethoxyisoquinolin-1-yl)methyl­ thio]benzimidazole (Ib - 1) To a suspension of 702 mg of the compound (Ia - 1) in 11 ml of CH₃CN was added 490 mg of 37 % aqueous solution of HCHO, and the mixture was stirred for 30 min. at 70 °C. It was filtered under cooling and washed with CH₃CN to give 705 mg of the objective compound 1-hydroxymethyl-2-[(6,7-dimethoxyisoquinolin-­ 1-yl)methylthio]benzimidazole (Ib - 1) (Yield : 92.8 %). m.p. : 156 - 158 °C (d) (recrystallized from AcOEt) Anal Calcd. (%) for C₂₀H₁₉N₃SO₃ : C, 62.98; H, 5.02; N, 11.02; S, 8.40 Found (%) : C, 63.03; H, 5.01; N, 10.86; S, 8.32 Example 23 - 24 (wherein R¹, R², R³ and R⁴ have the same meaning as defined above). In the same method as in Example 22, the reaction was performed under the reaction conditions as defined in Table 3, whereby the objective compounds (Ib) were obtained. Example 25 2-[(6,7-Dimethoxyisoquinolin-1-yl)methylthio]-1-butyryl­ oxymethylbenzimidazole (Ib - 2) To a solution of 534 mg of the compound (Ib - 1) in 12 ml of pyridine was added 0.67 ml of butyric anhydride, and the mixture was stirred for 4 hr. at room temperature. Under the reduced pressure, pyridine was evaporated, and the residue was extracted with CHCl₃, washed with water, dried and concentrated. The residue was subjected to silica gel column chromatography, eluting with AcOEt. Concentration of the eluate gave 540 mg of the objective compound 2-[(6,7-dimethoxyisoquinolin-1-yl)methyl­ thio]butyryloxymethylbenzimidazole (Yield : 85.4 %). m.p. : 149 - 151 °C (recrystallized from AcOEt) Anal Calcd. (%) for C₂₄H₂₅N₃O₂SO₄ : C, 63.84; H, 5.58; N, 9.31; S, 7.10 Found (%) : C, 63.89; H, 5.71; N, 9.24; S, 7.03 Example 26 - 28 (wherein R¹, R², R³ and R⁴ have the same meaning as defined above). In the same method as in Example 25, the reaction was performed under the reaction conditions as defined in Table 4, whereby the objective compounds (Ib) were obtained. Example 29 To a solution of 1.9 g of the compound (Ib - 1) and 1.39 ml of Et₃N in 120 ml of CHCl₃ was added 0.52 ml of ethyl chloro­ formate and the mixture was stirred for 2.5 hr. It was neutralized with saturated aqueous solution of NaHCO₃ and the CHCl₃ layer was dried and concentrated. The residue was subjected to silica gel column chromatography, eluting with CHCl₃ -AcOEt (4:1 v/v). Concentration of the former fraction gave 840 mg of the objective compound 1-ethoxycarbonyl-2-[(6,7-dimethoxyisoqui­ nolin-1-yl)methylthio]benzimidazole (Ib - 9) (Yield : 40.0 %). m.p. : 194 - 196 °C (recrystallized from AcOEt) Anal Calcd. (%) for C₂₂H₂₁N₃O₃SO₄ : C, 62.40; H, 5.00; N, 9.92; S, 7.57 Found (%) : C, 62.37; H, 4.95; N, 9.80; S, 7.46 Concentration of the latter fraction gave 1240 mg of the objective compound 1-ethoxycarbonyloxymethyl-2-[(6,7-dimethoxy­ isoquinolin-1-yl)methylthio]benzimidazole (Ib - 8) (Yield : 54.9 %). m.p. : 161 - 162 °C (recrystallized from AcOEt) Anal Calcd. (%) for C₂₃H₂₃N₃SO₅: C, 60.91; H, 5.11; N, 9.27; S, 7.07 Found (%) : C, 60.89; H, 5.19; N, 9.17; S, 7.21 Example 30 2-[(6,7-Dimethoxyisoquinolin-1-yl)methylsulfinyl]benz­ imidazole (Ic - 1) To a solution of 246.0 mg of 2-[(6,7-dimethoxyisoquino­ lin-1-yl)methylthio]benzimidazole (Ia - 1) (0.700 mmol) in 10 ml of CHCl₃, was added 151.0 mg of 80 % 3-CPBA (0.700 mmol) at -10 -­ -15 °C, and the mixture was stirred for 30 min. at the same tempe­ rature. The reaction mixture was mixed with 3 ml of saturated aqueous solution of NaHCO₃ and 0.3 ml of 10 % aqueous solution of NaHSO₃. The reaction temperature was returned to room temperature, and the reaction mixture was mixed with 2 ml of water and extracted with CHCl₃. The CHCl₃ layer was dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was subjected to silica gel column chromatography, eluting with AcOEt - MeOH. The obtained crystals were washed with CH₂Cl₂ - benzene to give 216.2 mg of the objective compound 2-[(6,7-dimethoxyisoquino­ lin-1-yl)methylsulfinyl]benzimidazole (Ic - 1) (Yield : 83.7 %). m.p. : 275 - 278 °C (d) Anal Calcd. (%) for C₁₉H₁₇N₃O₃S· 1/10 H₂O : C, 61.80; H, 4.70; N, 11.38; S, 8.68 Found (%) : C, 61.68; H, 4.70; N, 11.24; S, 8.71 Example 31 - 55 (wherein R¹, R², R³, R⁴, R⁵ and R have the same meaning as defined above). In the same method as in Example 30, the reaction was performed under the reaction conditions as defined in Table 5, whereby the objective compounds (Ic) and (Id) were obtained, respectively. Example 56 2-[(7-Allyloxy-6-methoxyisoquinolin-1-yl)methylsulfinyl]-­ 1-pivaloyloxymethylbenzimidazole (Id - 7) To a solution of 410 mg of the compound (Ic - 13) in 20 ml of DMF was added 46 mg of 60 % NaH (mineral oil suspension), and the mixture was stirred for 30 min., mixed with 0.158 ml of chloromethyl pivalate, stirred for 7 hr. and concentrated in vacuo. The residue was extracted with CHCl₃ and washed with water. The CHCl₃ layer was dried and concentrated. The residue was subjected with silica gel column chromatography, eluting with AcOEt. Concentration of the eluate gave 160 mg of the objective compound 2-[(7-allyloxy-6-methoxyisoquinolin-1-yl)methylsulfinyl]-­ 1-pivaloyloxymethylbenzimidazole (Id - 7) (Yield : 30.2 %). m.p. : 132 - 134 °C (d) Anal Calcd. (%) for C₂₇H₂₉N₃SO₅ : C, 63.89; H, 5.76; N, 8.28; S, 6.32 Found (%) : C, 63.86; H, 5.87; N, 8.09; S, 6.24 Example 57 2-[(6-Methoxyisoquinolin-1-yl)methylsulfinyl]-1-pivaloyl­ oxymethylbenzimidazole (Id - 8) In the same method as in Example 56, 675 mg of the compound (Ic - 16) was allowed to react with 88 mg of 60 % NaH (mineral oil suspension) and 0.3 ml of chloromethyl pivalate in 10 ml of DMF to give 0.28 g of the objective compound 2-[(6-methoxy­ isoquinolin-1-yl)methylsulfinyl]-1-pivaloyloxymethylbenzimidazole (Id - 8) (Yield : 31.3 %). m.p. : 125 - 127 °C (d) Anal Calcd. (%) for C₂₄H₂₅N₃SO₄ : C, 63.84; H, 5.58; N, 9,31; S, 7.10 Found (%) : C, 63.78; H, 5.69; N, 9.04; S, 6.90 Example 58 2-[(6,7-Dimethoxyisoquinolin-1-yl)methylsulfinyl]-1-­ pivaloyloxymethylbenzimidazole (Id - 9) In the same method as in Example 56, 331 mg of the compound (Ic - 1) was allowed to react with 40 mg of 60 % NaH (mineral oil suspension) and 142 mg of chloromethyl pivalate in 10 ml of DMF to give 210 mg of the objective compound 2-[(6,7-di­ methoxyisoquinolin-1-yl)methylsulfinyl]-1-pivaloyloxymethylbenz­ imidazole (Id - 9) (Yield : 48.4 %). m.p. : 114 - 116 °C (d) Anal Calcd. (%) for C₂₅H₂₇N₃SO₅ : C, 62.35; H, 5.65; N, 8.73; S, 6.66 Found (%) : C, 62.33; H, 5.87; N, 8.58; S, 6.50 Example 59 2-[(7-Benzyloxy-6-methoxy)isoquinolin-1-yl)methylsulfi­ nyl]-1-pivaloyloxymethylbenzimidazole (Id - 10) In the same method as in Example 56, 490 mg of the compound (Ib - 11) was allowed to react with 49 mg of 60 % NaH (mineral oil suspension) and 167 mg of chloromethyl pivalate in 20 ml of DMF to give 240 mg of the objective compound 2-[(7-benzyl­ oxy-6-methoxy)isoquinolin-1-yl)methylsulfinyl]-1-pivaloyloxy­ methylbenzimidazole (Id - 10) (Yield : 37.5 %). m.p. : 161 - 162 °C (d) Anal Calcd. (%) for C₃₁H₃₁N₃O₅ : C, 66.77; H, 5.60; N, 7.54; S, 5.75 Found (%) : C, 66.72; H, 5.66; N, 7.50; S, 5.60 Example 60 2-[(6,7-Dimethoxyisoquinolin-1-yl)methylsulfinyl]-1-­ phthalidylbenzimidazole (Id - 11) To 102.0 mg of 3-chlorophthalide (0.605 mmol) were added 1.1 ml of dry DMF and 83.5 mg of Et₃N (0.825 mmol), and the mixture was heated for 1.5 hr. at 65 - 70 °C to give the compound (VI). To the compound (VI) were added 91.2 mg of K₂CO₃ (0.66 mmol), 205.4 mg of 2-[(6,7-dimethoxyisoquinolin-1-yl)methylsulfi­ nyl]benzimidazole · 1/3 H₂O (0.55 mmol) and 1.3 ml of dry DMF, and the mixture was stirred for 2.5 hr. at room temperature, washed with water and extracted with CHCl₃. The CHCl₃ layer was dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was subjected to silica gel column chromatography, eluting with AcOEt. The obtained crystals were washed with AcOEt to give 248.0 mg of the objective compound 2-(6,7-dimethoxyisoquinolin-1-­ yl)methylsulfinyl-1-phthalydilbenzimidazole (Id - 10) (mixture of diastereomer ; Yield : 88.7 %). m.p. : 183.0 - 184.4 °C (d) Anal Calcd. (%) for C₂₇H₂₁N₃O₅S · 1/2 H₂O : : C, 63.77; H, 4.36; N, 8.26; S, 6.30 Found (%) : C, 63.96; H, 4.24; N, 8.13; S, 6.10 Example 61 2-{[(6-Methoxy-7-(2,2,2-trifluoroethoxy)isoquinolin-1-yl]­ methylthio}-1-pivaloyloxymethylbenzimidazole (Ib - 10) To a solution of 30.8 mg of 60 % NaH (0.77 mmol) in 5 ml of dry DMF was added 293.6 mg of 2-{[6-methoxy-7-(2,2,2-trifluoro­ ethoxy)isoquinolin-1-yl]methylthio}benzimidazole (Ia - 7) (0.7 mmol) and the mixture was stirred for 10 min. at room temperature. The mixture was mixed with 126.5 mg of chloromethyl pivalate, stirred for 2 hr. at room temperature and allowed to stand over­ night. After DMF was distilled off in vacuo, the residue was mixed with water and extracted with CH₂Cl₂. The CH₂Cl₂ layer was dried over anhydrous sodium sulfate and concentrated. The residue was subjected to silica gel column chromatography, eluting with CH₂Cl₂ - AcOEt. Crude product was washed with cyclohexane to give 344.7 mg of the objective compound 2-{[6-methoxy-7-(2,2,2-tri­ fluoroethoxy)isoquinolin-1-yl)methylthio}-1-pivaloyloxymethylbenz­ imidazole (Ib - 10) (Yield : 92.3 %). m.p. : 160.5 - 162.0 °C Anal Calcd. (%) for C₂₆H₂₆N₃O₄SF₃ : : C, 58.53; H, 4.91; N, 7.88; S, 6.01; F, 10.68 Found (%) : C, 58.38; H, 4.86; N, 7.77; S, 6.18; F, 10.90 Example 62 2-{[6-Methoxy-7-(2,2,2-trifluoroethoxy)isoquinolin-1-yl]­ methylsulfinyl}-1-pivaloyloxymethylbenzimidazole (Id - 12) In the same method as in Example 30, 324.0 mg of the compound (Ib - 10) was allowed to react with 261.9 mg of 80 % m-CPBA in 30 ml of CHCl₃ to give 135.4 mg of the objective compound 2-{[6-Methoxy-7-(2,2,2-trifluoroethoxy)isoquinolin-1-­ yl]-methylsulfinyl}-1-pivaloyloxymethylbenzimidazole (Id - 12) (Yield : 40.6 %). m.p. : 139.0 - 140.5 °C (d) Anal Calcd. (%) for C₂₆H₂₆N₃O₅SF₃ : C, 56.82; H, 4.77; N, 7.65; S, 5.83; F, 10.37 Found (%) : C, 57.00; H, 4.84; N, 7.48; S, 6.08; F, 10.25 Reference Example 1 To a solution of 3.96 g of vaniline (e-1) (26.0 mmol) in 26 ml of dry DMF was added 1.04 g of 60 % NaH (26.0 mmol) slowly, and the mixture was stirred for 30 min. in a stream of nitrogen. 2,2,2-Trifluoroethyl trifluoromethanesulfonate (6.64 g : 28.6 mmol) was added dropwise to the mixture and stirred overnight at room temperature. The reaction solution was poured into water and extracted with ether. The ether layer was washed with water, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was subjected to silica gel column chromatography, eluting with benzene - AcOEt to give 5.98 g of the objective compound 3-methoxy-4-(2,2,2-trifluoroethoxy)benzaldehyde (f-1) (Yield : 98.2 %). IR ν : 1260, 1690, 1595 (cm⁻¹) Reference Example 2 - 3 (wherein R² and R³ each has the same meaning as defined above, and Q and Q′ each is hydroxy or methoxy). In the same manner as in Reference Example 1, the reaction was performed under the reaction conditions as defined in Table 6, whereby the objective compounds (f) were obtained. Reference Example 4 To a mixture of 2.81 g of the compound (f-1) (12.0 mmol), 20 ml of EtOH and 1.46 g of nitromethane (24.0 mmol) were added dropwise 1.96 g of 86 % of KOH (30.0 mmol), 3 ml of water and 45 ml of MeOH under ice cooling, and the mixture was stirred for 30 min. at the same temperature. The reaction solution was poured into 30 ml of 15 % HCl. The precipitated crystals were collected by filtration, washed with water and dried to give 2.90 g of the crude crystals. It is subjected to silica gel column chromatogra­ phy, eluting with benzene - AcOEt to give 2.31 g of the objective compound 1-(2-nitroethenyl)-3-methoxy-4-(2,2,2-trifluoro­ ethoxy)benzene (g-1) (Yield : 69.4 %). IR ν : 1260, 1160, 1335 (cm⁻¹) Reference Example 5 - 6 (wherein R² and R³ have the same meaning as defined above). In the same manner as in Reference Example 4, the reaction was performed under the reaction conditions as defined in Table 7, whereby the objective compounds (g) were obtained. Reference Example 7 Under a nitrogen current 1.58 g of LiAlH₄ (41.6 mmol) was added to 15 ml of dry THF, and the mixture was dropwise added with 2.31 g of the compound (g-1) (8.32 mmol) and 30 ml of dry THF at 20 - 25 °C. After stirring for 2 hr., the mixture were mixed with 1.2 ml of AcOEt, 10 ml of hydrous ether and 6 ml of water in order under ice cooling. The temperature of the mixture was returned to room temperature and it was stirred for 1 hr. The mixture was filtered with a filtration aid and washed with THF. The crude objective compound 1-(2-aminoethyl)-3-methoxy-4-(2,2,2-­ trifluoroethoxy)benzene (h-1) (1.97 g ; Yield : 95.0 %) was obtained by concentrating in vacuo. NMR δ CDCl₃ : 1.42 (s, 2H); 2.57 - 3.05 (m, 4H); 3.85 (s, 3H); 4.34 (q, 2H); 6.60 - 7.00 (3H) Reference Example 8 - 9 (wherein R² and R³ each has the same meaning as defined above). In the same method as in Reference Example 7, the reaction was performed under the reaction conditions as defined in Table 8, whereby the objective compounds (h) were obtained. Reference Example 10 A solution of 3.05 g of 3-allyloxy-4-methoxyphenethyl­ amine (h-4) and 2.52 g of dichloromethyl acetate was stirred at 100 °C for 45 min. The mixture was concentrated under reduced pressure. The residue was subjected to silica gel column chromatography, eluting with CHCl₃. Concentration of the eluate gave 2.18 g of the objective compound N-(3-allyloxy-4-methoxy­ phenethy)dichloroacetamide (i-1) (Yield : 68.8 %). m.p. : 88 - 90 °C (recrystallized from AcOEt) Anal Calcd. (%) for C₁₄H₁₇Cl₂O₃ : C, 52.85; H, 5.39; N, 4.40; Cl, 22.28 Found (%) : C, 52.64; H, 5.42; N, 4.39; Cl, 22.00 Reference Example 11 - 22 (wherein R¹, R², R³ and R⁴ each has the same meaning as defined above). In the same method as in Reference Example 10, the reaction was performed under the reaction conditions as defined in Table 9, whereby the objective compounds (i) were obtained. Reference Example 23 To 1.18 g of N-[3-methoxy-4-(2,2,2-trifluoroethoxy)phe­ nyl]dichloroacetamide (3.28 mmol) were added 8 ml of xylene and 4.02 g of POCl, (26.2 mmol), and the mixture was refluxed for 2 hr. Xylene was distilled off under reduced pressure and ether was added to the residue. Then the mixture was extracted with 10 % HCl. The HCl layer was basified with 30 % NaOH and extracted with ether. The ether layer was dried over anhydrous sodium sulfate and concentrated in vacuo to give viscous liquid. It was subjected to silica gel column chromatography, eluting with CH₂Cl₂ -AcOEt to give 560.1 mg of the objective compound 1-dichloro­ methyl-6-methoxy-7-(2,2,2-trifluoroethoxy)-3,4-dihydroisoquinoline (j-1) (Yield : 49.9 %) as crystals. IR ν : 1155, 1270, 1320 (cm⁻¹) Reference Example 24 - 34 (wheein R² and R³ have the same meaning as defined above). In the same method as in Reference Example 23, the reaction was performed under the reaction conditions as shown in Table 10, whereby the objective compounds (j) were obtained. Experiment Antisecretory effect in a rat perfused stomach Jcl-SD rats (body weight : 300 g) were fasted for 24 hr. prior to the test. Rats were anesthetized with urethane, and the trachea and jugular vein were cannulated. The abdomen was incised along the median line. Respective perfusion cannulae were inserted into the antrum of stomach and the esophagus and fixed there. A warm physiological brine (37 °C) was perfused through the esophagus cannula at the rate of 1 ml/min., and the gastric effluent was collected at a constant interval through the antrum cannula. The perfusate was titrated with 0.01 N NaOH to determine the acid secretion. Acid secretion was continuously stimulated by intravenous infusion of histamine · 2 HCl (3 mg/kg/hr) through the jugular vein cannula. The test compounds were administered intra­ peritoneally 90 min. after the histamine and the infusate was further collected for 90 min. for titration as described above to determine the maximal suppression of acid secretion. Test compound Compound No. used herein corresponds to the number of Examples in which the compound was prepared. Evalution The percent suppression in acid secretion (%) was calculated from the acid secretion 90 min. after the histamine 2 HCl infusion and the acid secretion at the maximal suppression.

Claims: 1. A compound of the formula : (wherein R is hydrogen, hydroxy, methoxy, acetoxy, acetoxymethyl or trifluoromethyl; R¹, R², R³ and R⁴ each is hydrogen, hydroxy, optionally substi­ tuted C₁-C₅ alkoxy, acetoxy, propynyloxy, allyloxy or benzyloxy; or R² and R³ taken together form methylenedioxy; R⁵ is hydrogen, hydroxymethyl, C₂-C₄ alkoxycarbonyl, C₂-C₅ acyl­ oxymethyl or phthalidyl; and n is 0 or 1 except for the case in which R is methoxy and R¹, R², R³, R⁴ and R⁵ each is hydrogen) or its pharmaceutically acceptable acid addition salt. 2. A compound according to Claim 1, namely 2-[(6-methoxyisoquino­ lin-1-yl)methylsulfinyl]benzimidazole. 3. A pharmaceutical composition comprising a pharmacologically effective amount of a compound according to Claim 1 and a pharma­ ceutically acceptable carrier, diluent and/or excipient. 4. A compound of the formula (I) according to claim 1 for use in a method of treating a patient suffering from digestive ulcers. 5. Process for preparing a compound according to Claim 1 which comprises: a) reacting a compound of the formula: (wherein R is as defined above) with a compound of the formula: (wherein R¹, R², R³ and R⁴ each has the same meaning as defined above) to give a compound of the formula: (wherein R, R¹, R², R³ and R⁴ each has the same meaning as defined above), b) subjecting the compound (Ia) to (i) hydroxymethylation followed by O-acylation or (ii) N-substitution with halomethyl alkanoate or 3-halophthalide to give a compound of the formula: (wherein R, R¹, R², R³, R⁴ and R⁵ each has the same meaning as defined above), c) oxidizing the compound (Ia) to give a compound of the formula: (wherein R, R¹, R², R³ and R⁴ each has the same meaning as defined above), d) oxidizing the compound (Ib) to give a compound of the formula: (wherein R, R¹, R², R³ and R⁴ each has the same meaning as defined above and R⁵ is C₂-C₄ alkoxycarbonyl, C₂-C₅ acyloxymethyl or phthalidyl), or e) subjecting the compound (Ic) to N-substitution with halomethyl alkanoate or 3-halophthalide to give a compound of the formula: (wherein R, R¹, R², R³ and R⁴ each has the same meaning as defined above and R⁵ is C₂-C₅ acyloxymethyl or phthalidyl).

Inventors: HIRAI, KENTARO 720, UEMATSU-CHO, MIZUSHIMA, YUKIO
Applicants: SHIONOGI SEIYAKU KABUSHIKI KAISHA
Application year: 1987
Main classification: C07D401
IPC codes: C07D491, A61K31, C07D405, C07D401, C07D217, A61P1