Aldose reductase inhibitor

Abstract: The present invention relates to an aldose reductase inhibitor having the following formula: R₁ is a hydrogen atom or -A-COOR₅ (A is an alkylene group having 1 to 4 carbon atoms and R₅ is a hydrogen atom or a lower alkyl group), and R₂, R₃ and R₄ are the same as or different from each other and selected from the group consisting of a hydrogen atom, a hydroxy group, a halogen atom, a carboxyl group, an alkyl group, an amide group, an amino group, an alkoxy group, an aryl group, an aryloxy group, an alkylthio group, an alkylsulfinyl group, an alkylsulfonyl group, a nitro group, -NHCOCOOR₆ (R₆ is a hydrogen atom or a lower alkyl group), a mono- or dialkylaminosulfonyl group, and a residual group having the following formula: (A and R₅ are the same as in the above). The compounds defined in the above are excellent in aldose reductase inhibitory activity and low in toxicity. Therefore, those compounds are useful as a preventive agent and/or a remedy for diabetic complications such as neuropathy, retinopathy, nephropathy, cataracts and keratopathy.

Description: The present invention relates to an aldose reductase inhibitor. Namely, the present invention relates to an aldose reductase inhibitor containing the following compound of the general formula [I] as an effective component, wherein R₁ is a hydrogen atom or -A-COOR₅ (A is an alkylene group having 1 to 4 carbon atoms and R₅ is a hydrogen atom or a lower alkyl group), and R₂, R₃ and R₄ are the same as or different from each other and selected from the group consisting of a hydrogen atom, a hydroxy group, a halogen atom, a carboxyl group, an alkyl group, an amide group, an amino group, an alkoxy group, an aryl group, an aryloxy group, an alkylthio group, an alkylsulfinyl an alkylsulfonyl group, a nitro group, -NHCOCOOR₆ (R₆ is a hydrogen atom or a lower alkyl group), a mono- or dialkylaminosulfonyl group, and a residual group having the following formula: (A and R₅ are the same as in the above). An aldose reductase inhibitor is useful as a preventive agent and/or a remedy for diabetic complications. The diabetic complications appear in various forms, such as neuropathy, retinopathy, nephropathy, cataracts and keratopathy. It has been known that these diseases are triggered by hyperglycemia and caused by abnormal increase of the production of sorbitol in the polyol pathway to abnormally accumulate a large amount of sorbitol in the cells. The present aldose reductase inhibitor remarkably and effectively inhibits the activity of aldose reductase, which catalyzes the production of sorbitol in the polyol pathway, to prevent the production of sorbitol. As a result, the present aldose reductase inhibitor acts as a useful preventive agent/remedy for diabetic complications. Dr. Tsuyoshi Tanimoto [Division of Biological Chemistry and Reference Standards, National Institute of Hygienic Sciences] reported that aldose reductase inhibitors are effective for prevention/treatment of diabetic complications [FARUMASHIA, 24, No. 5, p. 459 ∼ 463 (1988) ]. This article discloses the chemical structures and IC₅₀ (concentrations for inhibiting activities by 50%) of representative aldose reductase inhibitors such as Alrestatin, Tolrestat, 4-Isopropyl-BPOC, Sorbinil, M-79175, Alconil, ADN-138, Epalrestat, CT-112 and Statil. The effective compounds having the formula [I] comprise both known and novel. For example, the compounds listed in Table 1 are described, as an antiallergic agent. The compounds listed in Table 2 are described in J. Org. Chem., 21 , 311 (1956). The compounds listed in Table 3 are also described in Zh. Org. Khim., 18 , 1981 (1982). EP-A-0 035 228 discloses tetrazole derivatives and their use in anti-ulcer compositions. Further tetrazole derivatives and their preparation are disclosed in R. Reap et al., Can. J. Chem. 47 , 813 (1969); F. Einberg, J. Org. Chem. 35 , 3978 (1970); A.K. Soerensen et al., Acta Chem. Scand. 26 , 541 (1972); T. Ishida et al., Bull. Chem. Soc. Jpn. 46 , 2176 (1973); G. Szeimies et al., Chem. Ber. 110 , 2922 (1977); Khim. Geterotsikl. Soedin. 1982, (2), 264-6; J.P. KOKAI No. 57-142977 and J.P. KOKAI No. 57-158767. J. Med. Chem. 13(4), p. 726-729 (1970) discloses the preparation of aryltetrazolyl alkanoic acids and their antiinflammatory activity. However, it has not been known until now that the present compounds have a useful inhibitory activity for aldose reductase. The object of the present invention is to provide an aldose reductase inhibitor which has an excellent inhibitory effect to aldose reductase and which is very effective as a preventive agent and/or a remedy for diabetic complications with low toxicity to human body. In the course of intensively studying the aminophenyl tetrazole derivatives in Table 1, which have been found to be useful as an antiallergic agent (J.P. Kokoku Nos. 59-1704, 59-1705 and 59-1707 and J.P. Kokai No. 63-44570), in respect of other pharmacological activities than the antiallergic activity, the present inventors have found out that those compounds have a very useful inhibitory activity for aldose reductase. In order to develop much excellent compounds, the present inventors have synthesized many compounds similar to the known compounds above and made intensive studies on those compounds including screening. As a result, the present inventors have found out that the novel compounds having the general formula [I] are very excellent aldose reductase inhibitors. The present invention has been completed based on this finding. Namely, the present invention relates to an aldose reductase inhibitor containing, as an effective component, a compound having the following general formula [I], wherein R₁ is -A-COOR₅ (A is an alkylene group having 1 to 4 carbon atoms and R₅ is a hydrogen atom or a lower alkyl group), and R₂, R₃ and R₄ are the same as or different from each other and selected from the group consisting of a hydrogen atom, a hydroxy group, a halogen atom, a carboxyl group, an alkyl group, an amide group, an amino group, an alkoxy group, an aryl group, an aryloxy group, an alkylthio group, an alkylsulfinyl group, an alkylsulfonyl group, a nitro group, - NHCOCOOR₆ (R₆ is a hydrogen atom or a lower alkyl group), a mono- or dialkylaminosulfonyl group, and a residual group having the following formula: (A and R₅ are the same as in the above), with the proviso that when A is -C(CH₃)₂- or -(CH₂)₂- and R₅ is a hydrogen atom or an ethyl group, or A is -CH₂- and R₅ is a hydrogen atom, a methyl group or an ethyl group, or A is -(CH₂)₃- or -(CH₂)₄- and R₅ is a hydrogen atom or a methyl group then R₂, R₃, and R₄ are not all hydrogen atoms, and when R₄ is 3- or 4-bromine, 3- or 4-chlorine, 3- or 4-nitro, 3- or 4-methyl or 3-trifluoromethyl then R₂ and R₃ are not simultaneously a hydrogen atom, A is not -CH₂- and R₅ is not a hydrogen atom nor an ethyl group. In the above formula, the alkylene group A comprises 1 to 4 carbon atoms. The group A may have a substituent such as an alkyl group like a methyl group. The lower alkyl group as R₅ is preferably those having 1 to 6 carbon atoms, more preferably 1 to 2 carbon atoms, such as a methyl group and an ethyl group. The alkyl group as R₂, R₃ or R₄ is preferably those having 1 to 10 carbon atoms, more preferably 1 to 7 carbon atoms. The amido group as R₂, R₃ or R₄ is generally those amido groups derived from monoalkyl amino compounds, dialkyl amino compounds, or cyclic amino compounds. Such monoalkyl amino compounds include those amine compounds having an alkyl group of C₁ to C₇. Such dialkyl amino compounds include those compounds having an alkyl group of C₁ to C₇. Such cyclic amino compounds include those compounds such as piperidine. The alkyl group of the alkoxy group, alkylthio group, alkyl sulfinyl group, alkylsulfonyl group or mono- or di-alkylaminosulfonyl group is preferably those having 1 to 7 carbon atoms. The phenyl or phenoxy group as R₂, R₃ or R₄ may have a substituent. The dosage per day of the present compound is dependent on the degree of the symptom of a patient. In general, it is 1 to 1000 mg per adult. The dosage is usually administered at one time or at several times. The administration can be made in any form. For example, it can be made orally, subcutaneously, intravenously, muscularly, or locally. The present compound is usually used in various forms, such as a tablet, a powder, a fine particle, a granule, a capsule, a ball, a solution, an injection, an eye drop, and the like, using additives, which are conventionally used, such as a diluent including sodium citrate, calcium carbonate, calcium phosphate and lactic acid, a disintegrator including corn starch and alginic acid, a binder including gelatin and acacia gum, and a lubricant including magnesium stearate, sodium lauryl sulfate and talc. The present compound can be synthesized as follows. In this case, the definitions of A and R₁∼ R₆ are the same as the above, Hal means a halogen atom, and Ar means In Reaction 1, the reaction is preferably conducted in a solvent such as methanol, ethanol or propanol, below the boiling point of the solvent. Reaction 2 corresponds to a tetrazole cyclization reaction. In this reaction, N-aryloylaminoalkyl carboxylate is reacted with a chlorinating agent such as phosphorus pentachloride or thionyl chloride, to produce an imidoylchloride, which is then reacted with sodium azide to give the object compound. The synthetic reaction of the imidoyl chloride can be conducted in a solvent such as benzene or toluene. The reaction temperature is preferably room temperature or lower. In the cyclization reaction, the intermediate imidoylchloride can be used without purifying it. Sodium azide is preferably used in an amount 1.5 to 3 times (in mole) that of the imidoylchloride. The reaction is preferably conducted in dimethylformamide at room temperature. Reaction 3 shows that if the compound wherein R₅ is a hydrogen atom is necessary to be produced, the carboxylate produced in Reaction 1 or 2 is merely hydrolyzed. This hydrolysis reaction can be conducted in the presence of a base such as sodium hydroxide or potassium hydroxide, or an acid such as hydrochloric acid, sulfuric acid, acetic acid or trifluoroacetic acid. Reaction 4 shows a representative process for synthesizing the compound having the formula [I] wherein R₂ is -NHCOCOOR₆ and indicates the reaction between an aminophenyl tetrazole having an amino group as a position where R₂ is introduced and an alkyl oxalate. This reaction can be conducted in an inert organic solvent which has been used for organic synthetic reactions. It is preferable that the reaction should be conducted using, as a solvent, a greatly excessive amount of the feed reactant, the alkyl oxalate (generally, 5 to 10 times (in mole) that of the other reactant). The reaction temperature is preferably 100 to 180°C. Reaction 5 shows that the compound obtained by Reaction 4 can be hydrolyzed at an ester position, if the compound wherein R₆ is a hydrogen atom is necessary to be obtained. The resultant compound having the formula [I] can be isolated and purified through the conventional chemical processes such as extraction, recrystallization or column chromatography. The purified compound is used as an effective component of an aldose reductase inhibitor. Example The present invention will be explained in detail below in reference to the following examples. Example 1 (Reaction 1) (1-1) Methyl 5-phenyl-1-tetrazoleacetate Two grams of 5-phenyltetrazole (13.68 mM) were slowly added to 5 ml of a methanol solution containing 770 mg (13.68 mM) of potassium hydroxide at room temperature. Two milli liters of a methanol solution containing 1.48 g (13.68 mM) of methyl chloroacetate were dropwise added to the resultant solution at room temperature. After the completion of the addition, the reaction solution was refluxed for 20 hours and cooled. The reaction solution was diluted with ethyl acetate and washed with water. The organic phase was dried over anhydrous magnesium sulfate and evaporated under reduced pressure. The residue was purified by silica gel chromatography (elute is chloroform), to give 0.54 g of methyl 5-phenyl-1-tetrazoleacetate (yield: 18.1%). N.M.R.(CDCl₃) δ : 3.81(s,3H), 5.21(s,2H), 7.35-7.67(m,5H) I.R. ν Na Cl cm⁻¹ : 2900, 1760, 1230 Mass: m/z 200[M⁺ ] The following compounds were produced in the same manner as Example 1(1-1). (1-2) Ethyl 5-phenyl-1-tetrazoleacetate Yield: 16.1% Feed materials: 5-phenyltetrazole and ethyl bromoacetate N.M.R.(CDCl₃) δ : 1.25(t,3H), 4.26(q,2H), 5.20(s,2H), 7.52-7.68(m,5H) I.R. ν Na Cl cm⁻¹ : 2980, 1750, 1220, 1020 Mass: m/z 232[M⁺ ] (1-3) Isopropyl 5-phenyl-1-tetrazoleacetate Yield: 16.6% Feed materials: 5-phenyltetrazole and isopropyl chloroacetate N.M.R.(CDCl₃) δ : 1.22(d,6H), 5.08(qq,1H), 5.17(s,2H), 7.52-7.69(m,5H) I.R. ν Na Cl cm⁻¹ : 2980, 1750, 1220 Mass: m/z 246[M⁺ ] (1-4) n-Butyl 5-phenyl-1-tetrazoleacetate Yield: 11.2% Feed materials: 5-phenyltetrazole and n-butyl chloroacetate N.M.R.(CDCl₃) δ : 0.90(t,3H), 1.30(qq,2H), 1.57(qq,2H), 4.20(t,2H), 5.2(s,2H), 7.52-7.68(m,5H) I.R. ν Na Cl cm⁻¹ : 2950, 1750, 1220 Mass: m/z 260[M⁺ ] (1-5) Methyl 5-(2-methylphenyl)-1-tetrazoleacetate Yield: 10.4% Feed materials: 5-(2-methylphenyl)tetrazole and methyl chloroacetate N.M.R.(CDCl₃) δ : 2.26(s,3H), 3.74(s,3H), 5.03(s,2H), 7.24-7.51(m,4H) I.R. ν Na Cl cm⁻¹ : 2950, 1760, 1220, 990 Mass: m/z 232[M⁺ ] (1-6) Methyl 5-(3-methylphenyl)-1-tetrazoleacetate Yield: 11.4% Feed materials: 5-(3-methylphenyl)tetrazole and methyl chloroacetate N.M.R.(CDCl₃) δ : 1.63(s,3H), 3.81(s,3H), 5.20(s,2H), 7.39-7.44(m,4H), 7.49(d,1H) I.R. ν Na Cl cm⁻¹ : 2950, 1750, 1220 Mass: m/z 232[M⁺ ] (1-7) Methyl 5-(4-methylphenyl)-1-tetrazoleacetate Yield: 10.4% Feed materials: 5-(4-methylphenyl)tetrazole and methyl-chloroacetate Melting point : 106 ∼ 107°C N.M.R.(CDCl₃) δ : 2.45(s,3H), 3.81(s,3H), 5.20(s,2H), 7.35(d,2H), 7.53(d,2H) I.R. ν KB r cm⁻¹ : 3270, 1750, 1610, 1480, 1250, 1220, 990, 830 Mass: m/z 232[M⁺ ] (1-8) Methyl 5-(4-methoxyphenyl)-1-tetrazoleacetate Yield: 8.5% Feed materials: 5-(4-methoxyphenyl)tetrazole and methyl chloroacetate N.M.R.(CDCl₃) δ : 3.82(s,3H), 3.88(s,3H), 5.20(s,2H), 7.05(d,2H), 7.59(d,2H) I.R. ν Na Cl cm⁻¹ : 3000, 2950, 1760, 1260, 840 Mass: m/z 249[M⁺ ] (1-9) Methyl 5-(4-fluorophenyl)-1-tetrazoleacetate Yield: 10.8% Feed materials: 5-(4-fluorophenyl)tetrazole and methyl chloroacaetate Melting point: 101 ∼ 102.5°C N.M.R.(CDCl₃) δ : 3.82(s,3H), 5.20(s,2H), 7.27(dd,2H), 7.70 (dd,2H) I.R. ν KB r cm⁻¹ : 2950, 1760, 1480, 1260, 610 Mass: m/z 236[M⁺ ] (1-10) Ethyl 3-(5-phenyltetrazol-1-yl)propionate Yield: 15. 1% Feed materials: 5-phenyltetrazole and ethyl 3-bromopropionate N.M.R.(CDCl₃) δ : 1.23(t,3H), 3.09(t,2H), 4.12(q,2H), 4.67(t,2H), 7.56-7.76(m,5H) I.R. ν Na Cl cm⁻¹ : 2980, 1730, 1460, 1200, 1020 Mass: m/z 246[M⁺ ] (1-11) Ethyl 4-(5-phenyltetrazol-1-yl)butyrate Yield: 14.2% Feed materials: 5-phenyltetrazole and ethyl 4-bromobutyrate N.M.R.(CDCl₃) δ : 1.22(t,3H), 2.28(qq,2H), 2.39(t,2H), 4.08(q,2H), 4.52(t,2H), 7.55-7.72(m,5H) I.R. ν Na Cl cm⁻¹ : 2980, 1720, 1470, 1200, 1010, 740 Mass: m/z 260[M⁺ ] (1-12) Ethyl 5-(5-phenyltetrazol-1-yl)valerate Yield: 13.2% Feed materials: 5-phenyltetrazole and ethyl 5-bromovalerate N.M.R.(CDCl₃) δ : 1.24(t,3H), 1.64(qq,2H), 2.00(qq,2H), 2.31(t,2H), 4.11(q,2H), 4.44(t,2H), 7.56-7.68(m,5H) I.R. ν Na Cl cm⁻¹ : 2980, 1730, 1470, 1180, 1030 Mass: m/z 274[M⁺ ] (1-13) Ethyl 2-(5-phenyltetrazol-1-yl)propionate Yield: 12.2% Feed materials: 5-phenyltetrazole and ethyl 2-bromopropionate N.M.R.(CDCl₃) δ : 1.22(t,3H), 1.98(d,3H), 4.22(q,2H), 5.23(q,1H), 7.62-7.72(m,5H) I.R. ν Na Cl cm⁻¹ : 2980, 1750, 1470, 1450, 1220, 690 Mass: m/z 246[M⁺ ] (1-14) Ethyl 2-(5-phenyltetrazol-1-yl)-2-methylpropionate Yield: 11.7% Feed materials: 5-phenyltetrazole and ethyl α-bromoisobutyrate N.M.R.(CDCl₃) δ : 1.20(t,3H), 2.08(s,6H), 4.20(q,2H), 7.63-7.69(m,5H) I.R. ν Na Cl cm⁻¹ : 2990, 1750, 1450, 1280, 1020, 740 Mass: m/z 260[M⁺ ] (1-15) Ethyl 5-(4-hydroxyphenyl)-1-tetrazoleacetate Yield: 22% Feed materials: 5-(4-hydroxyphenyl)tetrazole and ethyl bromoacetate N.M.R.(CDCl₃) δ : 1.27(t,3H,J=7.3Hz), 4.30(q,2H,J=7.3Hz), 5.19(s,2H), 7.01(d,2H,J=8.5Hz), 7.09(bs,1H), 7.52(d,2H,J=8.5Hz) I.R. ν Na Cl cm⁻¹ : 3190, 1750, 1610, 1480, 1220 Mass: m/z 277[M⁺ ] (1-16) Ethyl 5-(4-ethoxycarbonylmethoxycarbonylphenyl)-1-tetrazoleaetate Yield: 20% Feed materials: 5-(4-carboxyphenyl)tetrazole and ethyl bromoacetate N.M.R.(CDCl₃) δ : 1.27(t,3H,J=7.3Hz), 1.32(t,3H,J=7.3Hz), 4.27(q,2H,J=7.3Hz), 4.28(q,2H,J=7.3Hz), 4.90(s,2H), 5.22(s,2H), 7.79(dd,2H, J=1.6,6.4Hz), 8.28(dd,2H,J=1.6,6.4Hz) I.R. ν Na Cl cm⁻¹ : 3460, 2960, 1720, 1220, 1120, 1020 Mass: m/z 382[M⁺ ] (1-17) Ethyl 5-(4-piperidinocarbonylphenyl)-1-tetrazoleacetate Yield: 19% Feed materials: 5-(4-piperidinocarbonylphenyl)tetrazole and ethyl bromoacetate N.M.R.(CDCl₃) δ : 1.28(t,3H,J=7.25Hz), 1.55-1.71(m,6H), 3.34(bs,2H), 3.74(bs,2H), 4.27(q,2H,J=7.25Hz), 5.18(s,2H), 7.56(dd,2H,J=2.0,6.45Hz), 7.70(dd,2H,J=2.0,6.45Hz) I.R. ν Na Cl cm⁻¹ : 3470, 2940, 1750, 1630, 1440 Mass: m/z 342[M⁺ ] (1-18) Ethyl 5-(4-di-n-propylaminocarbonylphenyl)-1-tetrazoleacetate Yield: 15.4% Feed materials: 5-(4-di-n-propylaminocarbonylphenyl)tetrazole, and ethyl bromoacetate N.M.R.(CDCl₃) δ : 0.77(t,3H,J=6.9Hz), 1.03(t,3H,J=6.9Hz), 1.28(t,3H,J=6.9Hz), 1.54-1.73(m,4H), 3.17(t,2H,J=7.7Hz), 3.49(t,2H,J=7.7Hz), 4.27(q,2H,J=6.9Hz), 5.18(s,3H), 7.54(d,2H, J=8.1Hz),7.69(d,2H,J=8.1Hz) I.R. ν Na Cl cm⁻¹ : 3420, 2950, 1750, 1620, 1440 Mass: m/z 359[M⁺ ] Example 2 (Reaction 2) (2-1) Methyl 5-(4-chlorophenyl)-1-tetrazoleacetate Phosphorus pentachloride (500 mg, 2.88 mM) was slowly added to 13 ml of an anhydrous benzene containing 520 mg of N-(4-chlorobenzoyl)glycine methyl ester (2.29 mM) at room temperature. After stirring at room temperature for 30 min., the reaction mixture was evaporated at 40 °C under reduced pressure. The residue was dissolved in 5 ml of dimethylformamide. The solution was dropwise added to 2 ml of a dimethylformamide suspension containing 300 mg (4.6 mM) of sodium azide at room temperature over 40 to 60 min. while stirring it. After the completion of the addition, the mixture was additionally stirred at room temperature for 30 min. and poured into ice-water. The crystals as precipitated were collected by filtration, washed with water, dried under reduced pressure, and then recrystallized from methanol, to give 230 mg of the object product (yield: 40%). Melting point: 156 ∼ 158 °C N.M.R.(CDCl₃) δ : 3.81(s,3H), 5.38(s,2H), 7.96(d,2H), 8.42(d,2H) I.R. ν KB r cm⁻¹ : 3100, 2950, 1750, 1520, 1440, 1350, 1220 Mass: m/z 252[M⁺ ] The following compounds were prepared in the same manner as Example 2 (2-1). (2-2) Ethyl 5-phenyl-1-tetrazoleacetate Yield: 41.1% Feed material: N-benzoyl glycine ethyl ester The analysis data of the compound are the same as those of the compound of Example 1 (1-2). (2-3) Methyl 5-(4-methylphenyl)-1-tetrazoleacetate Yield: 50% Feed material: N-(4-methylbenzoyl)glycine methyl ester The analysis data of the compound are the same as those of the compound of Example 1 (1-7). (2-4) Methyl 5-(3-nitrophenyl)-1-tetrazoleacetate Yield: 31% Feed material: N-(3-nitrobenzoyl)glycine methyl ester Melting point: 122 ∼ 123°C N.M.R.(CDCl₃) δ : 3.86(s,3H), 5.53(s,2H), 7.80(t,1H), 8.47(dd,1H), 8.09(d,1H) I.R. ν KB r cm⁻¹ : 3000, 1750, 1540, 1520, 1340, 1220, 1000, 820, 710 Mass: m/z 263[M⁺ ] (2-5) Methyl 5-(4-nitrophenyl)-1-tetrazoleacetate Yield: 51% Feed material: N-(4-nitrobenzoyl)glycine methyl ester Melting point: 155 ∼ 156°C N.M.R.(CDCl₃) δ : 3.84(s,3H), 5.25(s,2H), 7.90(d,2H), 8.43(d,2H) I.R. ν KB r cm⁻¹ : 3100, 2950, 1750, 1520, 1440, 1350, 1220, 980, 850 Mass: m/z 263[M⁺ ] (2-6) Methyl 5-(3-nitro-4-chlorophenyl)-1-tetrazoleacetate Yield: 30% Feed material: N-(3-nitro-4-chlorobenzoyl)glycine methyl ester Melting point: 89 ∼ 91 °C N.M.R.(CDCl₃) δ : 3.79(s,3H), 5.19(s,2H), 7.71(d,1H), 7.83(d,1H), 8.16(d,1H) I.R. ν KB r cm⁻¹ : 3070, 3000, 2950, 1740, 1550, 1340, 1230, 1120 Mass: m/z 297[M⁺ ] (2-7) Methyl 5-(2-chloro-5-nitrophenyl)-1-tetrazoleacetate Yield: 39% Feed material: N-(2-chloro-5-nitrobenzoyl)glycine methyl ester Melting point: 128 ∼ 130°C N.M.R.(CDCl₃) δ : 3.75(s,3H), 5.17(s,2H), 7.79(dd,1H), 8.41(dd,1H), 8.45(s,1H) I.R. ν KB r cm⁻¹ : 3100, 3070, 3000, 2950, 1750, 1620, 1520, 1350, 1220 Mass: m/z 297[M⁺ ] (2-8) Butyl 3′-(1-ethoxycarbonylmethyl-tetrazol-5-yl)oxanilate Yield: 46.3% Feed material: N-[3-(butoxyoxamido)benzoyl]glycine ethyl ester Melting point: 103 ∼ 105°C N.M.R.(CDCl₃) δ : 0.99(t,3H), 1.27(t,3H), 1.45(qq,2H), 1.80(qq,2H), 4.30(q,2H), 4.37(t,2H), 5.27(s,2H), 7.56(d,2H), 7.71-7.74(m,1H), 8.13(d,1H), 9.05(bs,1H) I.R. ν KB r cm⁻¹ : 3100, 2950, 1740, 1700, 1600, 1280, 1220, 800 Mass: m/z 375[M⁺ ] (2-9) Methyl 5-(3-nitro-4-methylphenyl)-1-tetrazoleacetate Yield: 51% Feed material: N-(3-nitro-4-methylbenzoyl)glycine methyl ester Melting point: 85 ∼ 86 °C N.M.1.(CDCl₃) δ : 2.72(s,3H), 3.86(s,3H), 5.25(s,2H), 7.70(d,1H), 7.88(dd,1H), 8.29(d,1H) I.R. ν KB r cm⁻¹ : 3000, 2950, 1750, 1520, 1340, 1230 Mass: m/z 252[M⁺ ] (2-10) 1,4-Bis(1-methoxycarbonylmethyl-tetrazol-5-yl)benzene Yield: 40% Feed material: N,N′-bis(methoxycarbonylmethyl)terephthalamide Melting point: 182 ∼ 183°C N.M.R.(DMSO-d₆) δ : 3.68(s,6H), 5.73(s,4H), 8.0(s,4H) I.R. ν KB r cm⁻¹ : 3080, 3000, 2950, 1750, 1730, 1440, 1220 Mass: m/z 358[M⁺ ] (2-11) Methyl 5-(4-ethylphenyl)-1-tetrazoleacetate Yield: 36% Feed material: N-(4-ethylbenzoyl)glycine methyl ester N.M.R.(CDCl₃) δ : 1.29(t,3H), 2.74(dd,2H), 3.81(s,3H), 5.20(s,2H), 7.37(d,2H), 7.56(d,2H) I.R. ν Na Cl cm⁻¹ : 2950, 1750, 1620, 1480, 1440, 1220, 840 Mass: m/z 246[M⁺ ] (2-12) Methyl 5-(4-n-butylphenyl)-1-tetrazoleacetate Yield: 55% Feed material: N-(4-n-butylbenzoyl)glycine methyl ester N.M.R.(CDCl₃) δ : 0.94(t,3H), 1.39(qq,2H), 1.64(qq,2H), 2.70(t,2H), 3.81(s,3H), 5.20(s,2H), 7.45(d,2H), 7.55(d,2H) I.R. ν Na Cl cm⁻¹ : 2900, 1750, 1610, 1480, 1460, 1220 Mass: m/z 272[M⁺ ] (2-13) Methyl 5-(3-fluorophenyl)-1-tetrazoleacetate Yield: 40% Feed material: N-(3-fluorobenzoyl)glycine methyl ester N.M.R.(CDCl₃) δ : 3.83(s,3H), 5.22(s,2H), 7.28-7.60(m,4H) I.R. ν Na Cl cm⁻¹ : 2950, 1760, 1590, 1480, 1230, 880, 800 Mass: m/z 236[M⁺ ] (2-14) Methyl 5-(2-chlorophenyl)-1-terazoleacetate Yield: 45% Feed material: N-(2-chlorobenzoyl)glycine methyl ester N.M.R.(CDCl₃) δ : 3.71(s,3H), 5.13(s,2H), 7.27-7.59(m,4H) I.R. ν Na Cl cm⁻¹ : 3600, 2950, 1760, 1460, 1220, 990, 800 Mass: m/z 252[M⁺ ] (2-15) Methyl 5-(3,4-dimethylphenyl)-1-tetrazoleacetate Yield: 50% Feed material: N-(3,4-dimethylbenzoyl)glycine methyl ester N.M.R.(CDCl₃) δ : 2.33(s,6H), 3.81(s,3H), 5.20(s,2H), 7.30-7.31(m,2H), 7.45(s,1H) I.R. ν Na Cl cm⁻¹ : 2950, 1750, 1480, 1440, 1360, 1220, 990, 790 Mass: m/z 246[M⁺ ] (2-16) Methyl 5-(4-biphenylyl)-1-tetrazoleacetate Yield: 46.4% Feed material: N-(4-biphenyloyl)glycine methyl ester Melting point: 146 ∼ 147°C N.M.R.(CDCl₃) δ : 3.84(s,3H), 5.26(s,2H), 7.36-7.80(m,9H) I.R. ν KB r cm⁻¹ : 2910, 1760, 1730, 1470, 1210 Mass: m/z 294[M⁺ ] (2-17) Methyl 5-(4-n-heptylphenyl)-1-tetrazoleacetate Yield: 51% Feed material: N-(4-n-heptylbenzoyl)glycine methyl ester Melting point: 54 ∼ 55 °C N.M.R.(CDCl₃) δ : 0.88(t,3H), 1.28-1.36(m,8H), 1.64(m,2H), 2.69(t,2H), 3.82(s,3H), 5.20(s,2H), 7.35(d,2H), 7.55(d,2H) I.R. ν KB r cm⁻¹ : 2910, 2850, 1740, 1440, 1370, 1260, 1220 Mass: m/z 316[M⁺ ] (2-18) Methyl 5-(4-phenoxyphenyl)-1-tetrazoleacetate Yield: 46% Feed material: N-(4-phenoxybenzoyl)glycine methyl ester N.M.R.(CDCl₃) δ : 3.82(s,3H), 5.20(s,2H), 7.10-7.25(m,5H), 7.42(t,2H), 7.62(d,2H) I.R. ν Na Cl cm⁻¹ : 3000, 2950, 1750, 1610, 1580, 1470, 1440, 1360, 1240, 750 Mass: m/z 310[M⁺ ] (2-19) Methyl 5-(4-t-butylphenyl)-1-tetrazoleacetate Yield: 51% Feed material: N-(4-t-butylbenzoyl)glycine methyl ester N.M.R.(CDCl₃) δ : 1.37(s,9H), 3.83(s,3H), 5.21(s,2H), 7.58(s,4H) I.R. ν Na Cl cm⁻¹ : 2950, 1750, 1610, 1480, 1440, 1360, 1260, 1220, 1110, 1000, 840 Mass: m/z 274[M⁺ ] (2-20) Methyl 5-(4-n-butoxyphenyl)-1-tetrazoleacetate Yield: 46% Feed material: N-(4-n-butoxybenzoyl)glycine methyl ester N.M.R.(CDCl₃) δ : 0.99(t,3H), 1.47-1.61(m,2H), 1.78-1.82 (m,2H), 3.82(s,3H), 4.03(t,2H), 5.19(s,2H), 7.03(d,2H), 7.58(d,2H) I.R. ν Na Cl cm⁻¹ : 2950, 1760, 1610, 1480, 1250, 1220, 840 Mass: m/z 290[M⁺ ] (2-21) Methyl 5-(2-biphenylyl)-1-tetrazoleacetate Yield: 38% Feed material: N-(2-biphenyloyl)glycine methyl ester N.M.R.(CDCl₃) δ : 3.55(s,3H), 4.37(s,2H), 7.13-7.70(m,9H) I.R. ν Na Cl cm⁻¹ : 3000, 2950, 1760, 1430, 1220, 980 Mass: m/z 294[M⁺ ] (2-22) Methyl 5-(3,5-dimethylphenyl)-1-tetrazoleacetate Yield: 60% Feed material: N-(3,5-dimethylbenzoyl)glycine methyl ester N.M.R.(CDCl₃) δ : 2.39(s,6H), 3.82(s,3H), 5.20(s,2H), 7.23(s, 1H), 7.27(s,2H) I.R. ν Na Cl cm⁻¹ : 2960, 1760, 1470, 1440, 1240, 1220 Mass: m/z 246[M⁺ ] (2-23) Methyl 5-(3-trifluoromethylphenyl)-1-tetrazoleacetate Yield: 61% Feed material: N-(3-trifluoromethylbenzoyl)glycine methyl ester Melting point: 75 ∼ 76°C N.M.R.(CDCl₃) δ : 3.84(s,3H), 5.22(s,2H), 7.70-7.96(m,4H) I.R. ν KB r cm⁻¹ : 2970, 1750, 1440, 1340, 1230, 1120 Mass: m/z 286[M⁺ ] (2-24) Methyl 5-(4-n-heptoxyphenyl)-1-tetrazoleacetate Yield: 57.3% Feed material: N-(4-n-heptoxybenzoyl) glycine methyl ester Melting point: 51 ∼ 52 °C N.M.R.(CDCl₃) δ : 0.90(t,3H,J=6.45Hz), 1.32-1.46(m,2H), 1.80(m,2H), 3.82(s,3H), 4.03(t,4H,J=6.45Hz), 5.19(s,2H), 7.03(d,2H,J=8.86Hz), 7.58(d,2H, J=8.86Hz) I.R. ν KB r cm⁻¹ : 2950, 2850, 1760, 1620, 1260, 840 Mass: 332[M⁺ ] (2-25) Methyl 5-(3-methoxyphenyl)-1-tetrazoleacetate Yield: 42.8% Feed material: N-(3-methoxybenzoyl)glycine methyl ester N.M.R.(CDCl₃) δ : 3.82(s,3H), 3.86(s,3H), 5.21(s,2H), 7.10-7.22(m,3H), 7.43-7.49(m,1H) I.R. ν Na Cl cm⁻¹ : 3000, 2950, 1750, 1580, 1480, 1440, 1280, 1230, 1220, 1030 Mass: m/z 249[M⁺ ] (2-26) Methyl 5-(3,4-dimethoxyphenyl)-1-tetrazoleacetate Yield: 63.7% Feed material: N-(3,4-dimethoxybenzoyl)glycine methyl ester Melting point: 129.5 ∼ 130.5°C N.M.R.(CDCl₃) δ : 3.82(s,3H), 3.93(s,3H), 3.96(s,3H), 5.21(s, 2H), 6.99(d,1H,J=8.48Hz), 7.15(dd,1H,J=2.02, 8.46Hz), 7.27(d,1H,J=2.02Hz) I.R. ν KB r cm⁻¹ : 3000, 2950, 1750, 1610, 1500, 1440, 1240, 1020 Mass: m/z 278[M⁺ ] (2-27) Methyl 5-(3,4-di-n-butoxyphenyl)-1-tetrazoleacetate Yield: 74.5% Feed material: N-(3,4-di-n-butoxybenzoyl)glycine methyl ester Melting point: 77 ∼ 78 °C N.M.R.(CDCl₃) δ : 0.99(t,3H,J=7.25Hz), 1.00(t,3H,J=7.25Hz), 1.48-1.55(m,6H), 1.79-1.85(m,4H), 3.82(s,3H), 4.03(dd,2H,J=6.45,10.48Hz), 5.20(s,2H), 6.97(d,1H,J=8.46Hz), 7.10(dd,1H,J=2.02, 8.46Hz), 7.24(d,1H,J=2.02Hz) I.R. ν KB r cm⁻¹ : 2950, 1760, 1600, 1500, 1440, 1220 Mass: m/z 362[M⁺ ] (2-28) Methyl 5-(3,4,5-trimethoxyphenyl)-1-tetrazoleacetate Yield: 73.5% Feed material: N-(3,4,5-trimethoxybenzoyl)glycine methyl ester Melting point: 99.5 ∼ 100.5 °C N.M.R.(CDCl₃) δ : 3.84(s,3H), 3.89(s,6H), 3.92(s,3H), 5.21(s, 2H), 6.88(s,2H) I.R. ν KB r cm⁻¹ : 2950, 1740, 1590, 1500, 1440, 1240, 1120, 1000 Mass: m/z 308[M⁺ ] (2-29) Methyl 5-(4-bromomethylphenyl)-1-tetrazoleacetate Yield: 41% Feed material: N-(4-bromomethylbenzoyl)glycine methyl ester N.M.R.(CDCl₃) δ : 3.82(s,3H), 4.66(s,2H), 5.20(s,2H), 7.58(d, 2H,J=8.5Hz), 7.67(d,2H,J=8.5Hz) I.R. ν Na Cl cm⁻¹ : 3000, 2950, 1750, 1440, 1220, 990 Mass: m/z 311[M⁺ ] (2-30) Methyl 5-(4-methylthiophenyl)-1-tetrazoleacetate Yield: 44% Feed material: N-(4-methylthiobenzoyl)glycine methyl ester N.M.R.(CDCl₃) δ : 2.54(s,3H), 3.82(s,3H), 5.20(s,2H), 7.37(d, 2H,J=8.5Hz), 7.57(d,2H,J=8.5Hz) I.R. ν Na Cl cm⁻¹ : 3000, 2950, 1750, 1600, 1440, 1220 Mass: m/z 264[M⁺ ] (2-31) Methyl 5-(4-n-butylaminosulfonylphenyl)-1-tetrazoleacetate Yield: 38% Feed material: N-(4-n-butylaminosulfonylbenzoyl)glycine methyl ester N.M.R.(CDCl₃) δ : 0.88(t,3H,J=7.2Hz), 1.23-1.39(m,2H), 1.44-1.54(m,2H), 3.00-3.06(m,2H), 3.84(s,3H), 4.55(t,1H,J=6.0Hz), 5.23(s,2H), 7.83(dd,2H, J=1.6,8.5Hz), 8.05(dd,2H,J=1.6,8.5Hz) I.R. ν Na Cl cm⁻¹ : 3280, 2960, 1760, 1440, 1330 Mass: m/z 353[M⁺ ] (2-32) Methyl 5-(4-diisopropylaminosulfonylphenyl)-1-tetrazoleacetate Yield: 46% Feed material: N-(4-diisopropylaminosulfonylbenzyoyl)glycine methyl ester Melting point: 140 ∼ 141°C N.M.R.(CDCl₃) δ : 1.28(s,6H), 1.31(s,6H), 3.77(q,1H,J=6.65Hz), 3.83(s,3H), 5.21(s,2H), 7.79(dd,2H,J=1.6, 6.85Hz), 8.05(dd,2H,J=1.6, 6.85Hz) I.R. ν KB r cm⁻¹ : 3420, 1750, 1330, 1150 Mass: m/z 356[M⁺ ] (2-33) Methyl 5-(3,5-di-t-butyl-4-hydroxyphenyl)-1-tetrazoleacetate Yield: 40% Feed material: N-(3,5-di-t-butyl-4-hydroxybenzoyl)glycine methyl ester Melting point: 135 ∼ 137°C N.M.R.(CDCl₃) δ : 1.46(s,18H), 3.84(s,3H), 5.18(s,2H), 5.64(s, 1H), 7.45(s,2H) I.R. ν KB r cm⁻¹ : 3600, 2950, 1750, 1420, 1220, 1100 Mass: m/z 346[M⁺ ] (2-34) Methyl 5-(3,5-di-t-butyl-4-methoxyphenyl)-1-tetrazoleacetate Yield: 40% Feed material: N-(3,5-di-t-butyl-4-methoxybenzoyl)glycine methyl ester Melting point: 110 ∼ 111°C N.M.R.(CDCl₃) δ : 1.44(s,18H), 3.74(s,3H), 3.84(s,3H), 5.18(s, 2H), 7.52(s,2H) I.R. ν KB r cm⁻¹ : 2950, 1750, 1400, 1220, 1000 Mass: m/z 360[M⁺ ] Example 3 (Reaction 3) (3-1) 5-Phenyl-1-tetrazoleacetic acid A mixture of 100 mg of methyl 5-phenyl-1-tetrazoleacetate, 0.6 ml of acetic acid and 1 ml of a 4N-hydrochloric acid was stirred at 80 to 90°C for 2 hours. The reaction solution was evaporated under reduced pressure. The precipitated solid was filtered, washed with cold water and recrystallized from 50% ethanol-water, to give 64.1 mg (yield: 69.2%) of 5-phenyltetrazole-1-acetic acid. Melting point: 179 ∼ 180°C (decomposition) N.M.R.(DMSO-d₆) δ : 3.42(bs,3H), 5.51(s,2H), 7.59-7.78(m,5H) I.R. ν KB r cm⁻¹ : 3000, 2500, 1730, 1460, 1230 Mass: m/z 204[M⁺ ] The following compounds were obtained in the same manner as Example 3 (3-1). (3-2) 5-(3-Nitro-4-chlorophenyl)-1-tetrazoleacetic acid Yield: 41% Melting point: 189 to 190 °C (decomposition) Feed material: methyl 5-(3-nitro-4-chlorophenyl)-1-tetrazolacetate N.M.R.(DMSO-d₆) δ : 3.35(bs,4H), 5.59(s,3H), 8.01(d,2H), 8.48(d,1H) I.R. ν KB r cm⁻¹ : 3080, 3050, 2950, 1720, 1530, 1440, 1360, 1210 Mass: m/z 283[M⁺ ] (3-3) 5-(4-Fluorophenyl)-1-tetrazoleacetic acid Yield: 50% Feed material: methyl 5-(4-fluorophenyl)-1-tetrazoleacetate Melting point: 159 ∼ 160°C (decomposition) N.M.R.(DMSO-d₆) δ : 3.34(bs,3H), 5.51(s,2H), 7.34(dd,2H), 7.84(dd,2H) I.R. ν KB r cm⁻¹ : 3000, 2570, 1760, 1740, 1610, 1480, 1240,840 Mass: m/z 222[M⁺ ] (3-4) 5-(2-Methylphenyl)-1-tetrazoleacetic acid Yield: 58.7% Feed material: methyl 5-(2-methylphenyl)-1-tetrazoleacetate Melting point: 142 ∼ 143°C (decomposition) N.M.R.(DMSO-d₆) δ : 2.18(s,3H), 3.43(bs,3H), 5.25(s,2H), 7.35-7.55(m,4H) I.R. ν KB r cm⁻¹ : 3000, 2500, 1750, 1420, 1220, 1100, 820 Mass: m/z 218[M⁺ ] (3-5) 5-(3-Methylphenyl)-1-tetrazoleacetic acid Yield: 61.2% Feed material: methyl 5-(3-methylphenyl)-1-tetrazoleacetate Melting point: 140 ∼ 141.5°C (decomposition) N.M.R.(DMSO-d₆) δ : 2.40(s,2H), 3.42(bs,3H), 5.50(s,2H), 7.44-7.58(m,4H) I.R. ν KB r cm⁻¹ : 2920, 1730, 1220, 1210, 800 Mass: m/z 218[M⁺ ] (3-6) 5-(4-Methylphenyl)-1-tetrazoleacetic acid Yield: 80% Feed material: methyl 5-(4-methylphenyl)-1-tetrazoleacetate Melting point: 171 ∼ 172°C N.M.R.(DMSO-d₆) δ : 2.40(s,3H), 3.44(bs,3H), 5.49(s,2H), 7.42(d,2H), 7.64(d,2H) I.R. ν KB r cm⁻¹ : 3000, 2550, 1760, 1740, 1610, 1480, 1230, 820, 740 Mass: m/z 218[M⁺ ] (3-7) 5-(4-Methoxyphenyl)-1-tetrazoleacetic acid Yield: 58.7% Feed material: methyl 5-(4-methoxyphenyl)-1-tetrazoleacetate Melting point: 139 ∼ 140°C (decomposition) N.M.R.(DMSO-d₆) δ : 3.56(bs,3H), 3.85(s,3H), 5.48(s,2H), 7.15(d,2H), 7.70(d,2H) I.R. ν KB r cm⁻¹ : 3550, 3420, 2510, 1730, 1610, 1480, 1270, 840 Mass: m/z 234[M⁺ ] (3-8) 5-(3-Nitrophenyl)-1-tetrazoleacetic acid Yield: 70% Feed material: methyl 5-(3-nitrophenyl)-1-tetrazoleacetate Melting point: 215 ∼ 219°C (decomposition) N.M.R.(DMSO-d₆) δ : 3.35(bs,5H), 5.58(s,2H), 7.93(t,1H), 8.20(d,1H), 8.49(dd,1H), 8.56(s,1H) I.R. ν KB r cm⁻¹ : 2960, 1740, 1530, 1350, 1220 Mass: m/z 249[M⁺ ] (3-9) 5-(4-Nitrophenyl)-1-tetrazoleacetic acid Yield: 70.4% Feed material: methyl 5-(4-nitrophenyl)-1-tetrazoleacetate Melting point: 226 ∼ 227°C (decomposition) N.M.R.(DMSO-d₆) δ : 3.40(bs,1H), 5.60(s,2H), 8.07(d,2H), 8.43(d,2H) I.R. ν KB r cm⁻¹ : 3100, 2970, 2940, 1730, 1600, 1520, 1440, 1330, 1230, 1000, 860 Mass: m/z 249[M⁺ ] (3-10) 5-(4-Chlorophenyl)-1-tetrazoleacetic acid Yield: 50% Feed material: methyl 5-(4-chlorophenyl)-1-tetrazoleacetate Melting point: 225 ∼ 226°C (decomposition) N.M.R.(DMSO-d₆) δ : 3.34(bs,3H), 5.60(s,2H), 8.06(d,2H), 8.44(d,2H) I.R. ν KB r cm⁻¹ : 3100, 2970, 2950, 1740, 1520, 1440, 1340, 1240, 860 Mass: m/z 238[M⁺ ] (3-11) 5-(3-Nitro-4-methylphenyl)-1-tetrazoleacetic acid Yield: 68.5% Feed material: methyl 5-(3-nitro-4-methylphenyl)-1-tetrazoleacetate Melting point: 199 ∼ 200°C (decomposition) N.M.R.(DMSO-d₆) δ : 2.61(s,3H), 3.30(bs,3H), 5.58(s,2H), 7.50(d,1H), 8.00(dd,1H), 8.35(d,1H) I.R. ν KB r cm⁻¹ : 3050, 2970, 1730, 1530, 1210 Mass: m/z 263[M⁺ ] (3-12) 3′-(1-Carboxymethyl-tetrazol-5-yl)oxanilic acid Yield: 66% Feed material: butyl 3′-(1-ethoxycarbonylmethyl-tetrazol-5-yl) oxanilate Melting point: 220 ∼ 221°C (decomposition) N.M.R.(DMSO-d₆) δ : 3.17(s,2H), 5.49(s,2H), 7.28-7.55(m,4H) I.R. ν KB r cm⁻¹ : 2900, 2600, 1740, 1240 Mass: m/z 259[M⁺ ] (3-13) 1,4-Bis(1-carboxymethyl-tetrazol-5-yl)benzene Yield: 72.3% Feed material: 1,4-bis(methoxycarbonylmethyl-tetrazole-5-yl) benzene Melting point: 263 ∼ 264°C (decomposition) N.M.R.(DMSO-d₆) δ : 3.54(bs,10H), 5.59(s,4H), 8.01(s,4H) I.R. ν KB r cm⁻¹ : 3000, 2950, 2570, 1760, 1730, 1460, 1230, 800 Mass: m/z 300[M⁺ ] (3-14) 5-(4-n-Butylphenyl)-1-tetrazoleacetic acid Yield: 52% Feed material: methyl 5-(4-n-butylphenyl)-1-tetrazoleacetate Melting point: 119 ∼ 120°C N.M.R(DMSO-d₆)δ : 0.91(t,3H), 1.35(qq,2H), 1.59(qq,2H), 2.67(t,2H), 2.50(bs,3H), 5.50(s,2H), 7.43(d,2H), 7.67(d,2H) I.R. ν KB r cm⁻¹ : 3000, 2950, 2920, 1730, 1240 Mass: m/z 260[M⁺ ] (3-15) 3-(5-Phenyltetrazol-1-yl)propionic acid Yield: 70.4% Feed material: ethyl 3-(5-phenyltetrazol-1-yl)propionate Melting point: 116 ∼ 118°C (decomposition) N.M.R.(DMSO-d₆) δ : 2.99(t,2H), 3.38(bs,1H), 4.62(t,2H), 7.64-7.83(m,5H) I.R. ν KB r cm⁻¹ : 2900, 1720, 1310, 1200, 700 Mass: m/z 218[M⁺ ] (3-16) 4-(5-Phenyltetrazol-1-yl)butyric acid Yield: 68.1% Feed material: ethyl 4-(5-phenyltetrazol-1-yl)butyrate Melting point: 131 ∼ 132°C (decomposition) N.M.R.(DMSO-d₆) δ : 2.04(qq,2H), 2.30(t,2H), 3.34(bs,3H), 4.52(t,2H), 7.62-7.81(m,5H) I.R. ν KB r cm⁻¹ : 2950, 1730, 1460, 1200, 780 Mass: m/z 232[M⁺ ] (3-17) 5-(5-Phenyltetrazol-1-yl)valeric acid Yield: 65.5% Feed material: ethyl 5-(5-phenyltetrazol-1-yl)valerate Melting point: 105 ∼ 106°C (decomposition) N.M.R.(DMSO-d₆) δ : 1.44(qq,2H), 1.83(qq,2H), 2.19(t,2H), 3.34(bs,3H), 4.49(t,2H), 7.64-7.67(m,5H) I.R. ν KB r cm⁻¹ : 2950, 1720, 1460, 1210, 740 Mass: m/z 246[M⁺ ] (3-18) 2-(5-Phenyltetrazol-1-yl)propionic acid Yield: 64.1% Feed material: ethyl 2-(5-phenyltetrazol-1-yl)propionate Melting point: 187 ∼ 188°C (decomposition) N.M.R.(DMSO-d₆) δ : 1.83(d,3H), 3.35(bs,3H), 5.55(q,1H), 7.62-7.72(m,5H) I.R. ν KB r cm⁻¹ : 2900, 2550, 1740, 1460, 1240, 1180, 740 Mass: m/z 218[M⁺ ] (3-19) 2-(5-Phenyltetrazol-1-yl)-2-methylpropionic acid Yield: 66.9% Feed material: ethyl 2-(5-phenyltetrazol-1-yl)-2-methylpropionate Melting point: 184 ∼ 185°C (decomposition) N.M.R.(DMSO-d₆) δ : 2.79(s,6H), 3.34(bs,3H), 7.63-7.78(m,5H) I.R. ν KB r cm⁻¹ : 2950, 1740, 1450, 1190, 990, 730, 680 Mass: m/z 232[M⁺ ] (3-20) 5-(3-Fluorophenyl)-1-tetrazoleacetic acid Yield: 60% Feed material: ethyl 5-(3-fluorophenyl)-1-tetrazoleacetate Melting point: 134 ∼ 135°C (decomposition) N.M.R.(DMSO-d₆) δ : 3.33(bs,3H), 5.56(s,2H), 7.49-7.72(m,4H) I.R. ν KB r cm⁻¹ : 3000, 2910, 2590, 1740, 1480, 1240, 880 Mass: m/z 222[M⁺ ] (3-21) 5-(2-Chlorophenyl)-1-tetrazoleacetic acid Yield: 58% Feed material: methyl 5-(2-chlorophenyl)-1-tetrazoleacetate Melting point: 155 ∼ 157°C (decomposition) N.M.R.(DMSO-d₆) δ : 3.34(bs,3H), 5.30(s,2H), 7.58(d,1H), 7.64-7.75(m,2H) I.R. ν KB r cm⁻¹ : 3000, 2960, 2520, 1730, 1600, 1440, 1220, 810, 750 Mass: m/z 238[M⁺ ] (3-22) 5-(3,4-Dimethylphenyl)-1-tetrazoleacetic acid Yield: 60% Feed material: methyl 5-(3,4-dimethylphenyl)-1-tetrazoleacetate Melting point: 225 ∼ 226 °C (decomposition) N.M.R.(DMSO-d₆) δ : 2.30(s,6H), 5.49(s,2H), 7.36(d,1H), 7.47(d,1H), 7.54(s,1H) I.R. ν KB r cm⁻¹ : 2920, 1730, 1460, 1220, 840 Mass: m/z 232[M⁺ ] (3-23) 5-(4-Biphenylyl)-1-tetrazoleacetic acid Yield: 76.8% Feed material: methyl 5-(4-biphenyly)-1-tetrazoleacetate Melting point: 183 ∼ 184°C (decomposition) N.M.R.(DMSO-d₆) δ : 3.35(bs,2H), 5.51(s,2H), 7.41-7.94(m,9H) I.R. ν KB r cm⁻¹ : 3420, 2930, 1740, 1480, 1220 Mass: m/z 280[M⁺ ] (3-24) 5-(4-n-Heptylphenyl)-1-tetrazoleacetic acid Yield: 81% Feed material: methyl 5-(4-n-heptylphenyl)-1-tetrazoleacetate Melting point: 127 ∼ 129°C (decomposition) N.M.R.(CDCl₃) δ : 0.89(t,3H), 1.25-1.34(m,8H), 1.62-1.68(m, 2H), 2.69(t,2H), 5.15(s,2H), 7.35(d,2H), 7.60(d,2H) I.R. ν KB r cm⁻¹ : 2910, 2850, 1760, 1740, 1240 Mass: m/z 302[M⁺ ] (3-25) 5-(4-Phenoxyphenyl)-1-tetrazoleacetic acid Yield: 69% Feed material: methyl 5-(4-phenoxyphenyl)-1-tetrazoleacetate Melting point: 161 ∼ 161.5°C (decomposition) N.M.R.(DMSO-d₆) δ : 5.16(s,2H), 7.10-7.45(m,7H), 7.66(d,2H) I.R. ν KB r cm⁻¹ : 3000, 2950, 1760, 1730, 1580, 1470, 1240 Mass: m/z 296[M⁺ ] (3-26) 5-(4-t-Butylphenyl)-1-tetrazoleacetic acid Yield: 55% Feed material: methyl 5-(4-t-Butylphenyl)-1-tetrazoleacetate Melting point: 186 ∼ 187°C (decomposition) N.M.R.(DMSO-d₆) δ : 1.33(s,9H), 5.50(s,2H), 7.66(q,4H) I.R. ν KB r cm⁻¹ : 2950, 1740, 1730, 1480, 1430, 1220, 840 Mass: m/z 260[M⁺ ] (3-27) 5-(4-n-Butoxyphenyl)-1-tetrazoleacetic acid Yield: 63% Feed material: methyl 5-(4-n-butoxyphenyl)-1-tetrazoleacetate Melting point: 135 ∼ 136°C (decomposition) N.M.R.(DMSO-d₆) δ : 0.95(t,3H), 1.45(q,2H), 1.72(q,2H), 4.06(t,2H), 5.45(s,2H), 7.13(d,2H), 7.68(d,2H) I.R. ν KB r cm⁻¹ : 2920, 1760, 1730, 1620, 1480, 1250 Mass: m/z 276[M⁺ ] (3-28) 5-(2-Biphenylyl)-1-tetrazoleacetic acid Yield: 50% Feed material: methyl 5-(2-Biphenylyl)-1-tetrazoleacetate N.M.R.(DMSO-d₆) δ : 4.36(s,2H), 7.06-7.64(m,9H), 7.84(bs,2H) I.R. ν Na Cl cm⁻¹ : 3000, 2950, 1740, 1430, 1250 Mass: m/z 280[M⁺ ] (3-29) 5-(3,5-Dimethylphenyl)-1-tetrazoleacetic acid Yield: 76% Feed material: methyl 5-(3,5-dimethylphenyl)-1-tetrazoleacetate Melting point: 187 ∼ 188°C (decomposition) N.M.R.(DMSO-d₆) δ : 2.35(s,6H), 3.33(bs,2H), 5.49(s,2H), 7.27(s,1H), 7.35(s,2H) I.R. ν KB r cm⁻¹ : 2920, 1730, 1220, 860 Mass: m/z 232[M⁺ ] (3-30) 5-(3-Trifluoromethylphenyl)-1-tetrazoleacetic acid Yield: 67% Feed material: methyl 5-(3-trifluoromethylphenyl)-1-tetrazoleacetate Melting point: 169 ∼ 170°C (decomposition) N.M.R.(DMSO-d₆) δ : 3.35(bs,2H), 5.60(s,2H), 7.88-8.11(m,4H) I.R. ν KB r cm⁻¹ : 3000, 1740, 1450, 1330, 1240, 1120 Mass: m/z 272[M⁺ ] (3-31) 5-(4-Hydroxyphenyl)-1-tetrazoleacetic acid Yield: 82% Feed material: ethyl 5-(4-hydroxyphenyl)-1-tetrazoleacetate Melting point: 220 ∼ 222°C (decomposition) N.M.R.(DMSO-d₆) δ : 5.16(s,2H), 4.7-6.4(bs,1H), 7.00(dd,2H, J=2.6,9.2Hz), 7.52(dd,2H,J=2.6,9.2Hz), 9.70(bs,1H) I.R. ν KB r cm⁻¹ : 3140, 1730, 1600, 1470, 1280 Mass: m/z 220[M⁺ ] (3-32) 5-(4-n-Heptoxyphenyl)-1-tetrazoleacetic acid Yield: 70% Feed material: methyl 5-(4-n-heptoxyphenyl)-1-tetrazoleacetate Melting point: 131 ∼ 132°C (decomposition) N.M.R.(CDCl₃ + DMSO-d₆) δ : 0.90(t,3H,J=6.44Hz), 1.33-1.48(m, 8H), 1.80(m,2H), 4.02(t,2H, J=6.60Hz), 5.13(s,2H), 7.02(d,2H, J=8.87Hz), 7.63(d,2H,J=8.46Hz) I.R. ν KB r cm⁻¹ : 3000, 2900, 1730, 1610, 1480, 1250, 1230, 740 Mass: m/z 318[M⁺ ] (3-33) 5-(3-Methoxyphenyl)-1-tetrazoleacetic acid Yield: 71.9% Feed material: methyl 5-(3-methoxyphenyl)-1-tetrazoleacetate Melting point: 179.5 ∼ 180.5°C (decomposition) N.M.R.(DMSO-d₆) δ : 3.86(s,3H), 5.21(s,2H), 7.12-7.44(m,3H), 7.47-7.55(m,1H) I.R. ν KB r cm⁻¹ : 3000, 2500, 1730, 1600, 1540, 1490, 1240, 1120, 1020, 800 Mass: m/z 234[M⁺ ] (3-34) 5-(3,4-Dimethoxyphenyl)-1-tetrazoleacetic acid Yield: 72.4% Feed material: methyl 5-(3,4-dimethoxyphenyl)-1-tetrazoleacetate Melting point: 193.5 ∼ 194.5°C (decomposition) N.M.R.(CDCl₃ + DMSO-d₆) δ : 3.92(s,3H), 3.96(s,3H), 5.17(s, 2H), 7.01(d,1H,J=8.46Hz), 7.22(dd, 1H,J=2.01,8.46Hz), 7.28(d,1H, J=2.42Hz) I.R. ν KB r cm⁻¹ : 3000, 1730, 1610, 1500, 1460, 1220, 1020, 820 Mass: m/z 264[M⁺ ] (3-35) 5-(3,4-Di-n-butoxyphenyl)-1-tetrazoleacetic acid Yield: 71.1% Feed material: methyl 5-(3,4-di-n-butoxyphenyl)-1-tetrazoleacetate Melting point: 141 ∼ 142°C (decomposition) N.M.R.(DMSO-d₆) δ : 0.99(t,3H,J=7.0Hz), 1.00(t,3H,J=7.0Hz), 1.45-1.60(m,4H), 1.76-1.89(m,4H), 4.01-4.10(m,4H), 6.98-7.38(m,4H) I.R. ν KB r cm⁻¹ : 3420, 2950, 1730, 1610, 1500, 1460, 1210, 1140, 810 Mass: m/z 348[M⁺ ] (3-36) 5-(3,4,5-Trimethoxyphenyl)-1-tetrazoleacetic acid Yield: 87% Feed material: methyl 5-(3,4,5-trimethoxyphenyl)-1-tetrazoleacetate Melting point: 234 ∼ 235°C (decomposition) N.M.R.(CDCl₃ + DMSO-D₆) δ : 3.89(s,3H), 3.92(s,3H), 5.18(s, 2H), 6.94(s,2H), I.R. ν KB r cm⁻¹ : 3000, 2950, 1730, 1590, 1490, 1420, 1220, 1120, 1000 Mass: m/z 294[M⁺ ] (3-37) 5-(4-Carboxyphenyl)-1-tetrazoleacetic acid Yield: 85% Feed material: ethyl 5-(4-ethoxycarbonylmethoxycarbonylphenyl)-1-tetrazoleacetate Melting point: 271 ∼ 273°C (decomposition) N.M.R.(DMSO-d₆) δ : 2.7-4.8(br,1H), 5.44(s,2H), 7.36(d,2H, J=8.4Hz), 8.16(d,2H,J=8.4Hz), 12.2-13.7 (br,1H) I.R. ν KB r cm⁻¹ : 3420, 1740, 1690, 1420, 1290, 1240 Mass: m/z 248[M⁺ ] (3-38) 5-(4-Piperidinocarbonylphenyl)-1-tetrazoleacetic acid Yield: 88% Feed material: ethyl 5-(4-piperidinocarbonylphenyl)-1-tetrazoleacetate Melting point: 226 ∼ 227°C (decomposition) N.M.R.(DMSO-d₆) δ : 1.56(bs,2H), 1.71(bs,2H), 3.36(bs,2H), 3.72(bs,2H), 3.2-5.0(br,1H), 5.23(s,2H), 7.57(d,2H,J=8.4Hz), 7.77(d,2H,J=8.4Hz) I.R. ν KB r cm⁻¹ : 3430, 2930, 1740, 1570, 1450 Mass: m/z 314[M⁺ ] (3-39) 5-(4-Di-n-propylaminocarbonylphenyl)-1-tetrazoleacetic acid Yield: 88% Feed material: ethyl 5-(4-di-n-propylaminocarbonylphenyl)-1-tetrazoleacetate Melting point: 188 ∼ 189°C (decomposition) N.M.R.(DMSO-d₆) δ : 0.77(t,3H,J=7.3Hz), 1.00(t,3H,J=7.3Hz), 1.56(q,t,2H,J=7.3,7.7Hz), 1.71(q,t,2H, J=7.8,7.7Hz), 3.18(t,2H,J=7.7Hz), 3.47 (t,2H,J=7.7Hz), 3.73(br,1H), 5.22(s,2H), 7.53(d,2H,J=8.3Hz), 7.76(d,2H,J=8.3Hz) I.R. ν KB r cm⁻¹ : 3400, 2900, 1730, 1560, 1220 Mass: m/z 331[M⁺ ] (3-40) 5-(4-Aminophenyl)-1-tetrazoleacetic acid Yield: 42.6% Feed material: methyl 5-(4-aminophenyl)-1-tetrazoleacetate Melting point: 183°C (decomposition) N.M.R.(DMSO-d₆) δ : 5.03(s,2H), 6.66(d,2H,J=8.46Hz), 7.45(d, 2H,J=8.86Hz) I.R. ν KB r cm⁻¹ : 3420, 1760, 1620, 1480, 1370, 830 Mass: m/z 219[M⁺ ] (3-41) 5-(4-Bromomethylphenyl)-1-tetrazoleacetic acid Yield: 75% Feed matrial: methyl 5-(4-bromomethylphenyl)-1-tetrazoleacetate Melting point: 171 ∼ 173°C (decomposition) N.M.R.(DMSO-d₆) δ : 4.56(s,2H), 5.48(s,2H), 7.54(d,2H, J=8.46Hz), 7.74(d,2H,J=8.46Hz) I.R. ν KB r cm⁻¹ : 3200, 2980, 1760, 1420, 1220 Mass: m/z 297[M⁺ ] (3-42) 5-(4-Methylthiophenyl)-1-tetrazoleacetic acid Yield: 80% Feed material: methyl 5-(4-methylthiophenyl)-1-tetrazoleacetate Melting point: 160 ∼ 163°C (decomposition) N.M.R.(DMSO-d₆) δ : 2.55(s,2H), 3.44(bs,3H), 5.49(s,2H), 7.46 (d,2H,J=8.46Hz), 7.69(d,2H,J=8.46Hz) I.R. ν KB r cm⁻¹ : 3400, 2900, 1740, 1600, 1200 Mass: m/z 250[M⁺ ] (3-43) 5-(4-Methylsulfinylphenyl)-1-tetrazoleacetic acid Yield: 74% Feed material: methyl 5-(4-methylsulfinylphenyl)-1-tetrazoleacetate Melting point: 238 ∼ 240°C (decomposition) N.M.R.(DMSO-d₆) δ : 2.82(s,3H), 5.43(s,2H, 7.91(d,2H, J=8.46Hz), 7.93(d,2H,J=8.46Hz) I.R. ν KB r cm⁻¹ : 3420, 2500, 1760, 1460, 1230, 1000 Mass: m/z 301[M⁺ ] (3-44) 5-(4-Methylsulfonylphenyl)-1-tetrazoleacetic acid Yield: 72% Feed material: methyl 5-(4-methylsulfonylphenyl)-1-tetrazoleacetate Melting point: 214 ∼ 216°c (decomposition) N.M.R.(DMSO-d₆) δ : 3.19(s,3H), 5.34(s,2H), 8.00(d,2H, J=8.46Hz), 8.15(d,2H,J=8.46Hz) I.R. ν KB r cm⁻¹ : 3000, 1730, 1300, 1240, 1150 Mass: m/z 317 [M ⁺ ] (3-45) 5-(4-n-Butylaminosulfonylphenyl)-1-tetrazoleacetic acid Yield: 78% Feed material: methyl 5-(4-n-butylaminosulfonylphenyl)-1-tetrazoleacetate Melting point: 148 ∼ 149°C (decomposition) N.M.R.(DMSO-d₆) δ : 0.87(t,3H,J=7.3Hz), 1.25-1.53(m,4H), 2.89-2.94(m,2H), 3.20-4.30(br,1H), 5.23(s,2H), 7.11(t,1H,J=5.1Hz), 7.86(d,1H,J=8.7Hz), 8.05(d,1H,J=8.7Hz) I.R. ν KB r cm⁻¹ : 3560, 3270, 2950, 1740, 1440, 1320, 1240, 1160, 1090 Mass: m/z 339[M⁺ ] (3-46) 5-(4-Diisopropylaminosulfonylphenyl)-1-tetrazoleacetic acid Yield: 87% Feed material: methyl 5-(4-diisopropylaminosulfonylphenyl)-1-tetrazoleacetate Melting point: 215 ∼ 216°C (decomposition) N.M.R.(DMSO-d₆) δ : 1.28(s,6H), 1.30(s,6H), 3.77(q,1H, J=6.6Hz), 3.7-4.2(br,1H), 5.26(s,2H), 7.88(d,2H,J=7.7Hz), 8.03(d,2H,J=7.7Hz) I.R. ν KB r cm⁻¹ : 3420, 2970, 1740, 1440, 1320 Mass: m/z 367[M⁺ ] (3-47) 5-(3,5-Di-t-butyl-4-hydroxyphenyl)-1-tetrazoleacetic acid Yield: 62% Feed material: methyl 5-(3,5-di-t-butyl-4-hydroxyphenyl)-1-tetrazoleacetate Melting point: 118 ∼ 119°C (decomposition) N.M.R.(DMSO-d₆) δ : 1.40(s,18H), 3.36(bs,1H), 5.09(s,2H), 7.53 (s,2H), 7.63(s,1H) I.R. ν KB r cm⁻¹ : 3440, 2950, 1610, 1420, 1380, 1240 Mass: m/z 332[M⁺ ] (3-48) 5-(3,5-Di-t-butyl-4-methoxyphenyl)-1-tetrazoleacetic acid Yield: 78% Feed material: methyl 5-(3,5-di-t-butyl-4-methoxyphenyl)-1-tetrazoleacetate Melting point: 164 ∼ 165°C (decomposition) N.M.R.(DMSO-d₆) δ : 1.41(s,18H), 3.35(bs,1H), 3.71(s,3H), 5.38 (s,2H), 7.60(s,2H) I.R. ν KB r cm⁻¹ : 3440, 2950, 1740, 1450, 1410, 1230 Mass: m/z 346[M⁺ ] Example 4 (Reaction 4) (4-1) 5-(3-n-Butyloxalylaminophenyl)tetrazole 5-(3-Aminophenyl)tetrazole (1.7 g) was added to 12 ml of n-butyloxalate and reacted at a bath temperature of 165 to 175°C for 1. 5 hr while stirring. After cooling, the precipitated crystals were filtered off and recrystallized from acetone-n-hexane, to give 2.3 g (yield: 75%) of 5-(3-n-butyloxalylaminophenyl)tetrazole. Melting point: 157 ∼ 158°C (J.P. Kokoku No. 59-1705) The following compounds were obtained in the same manner as Example 4 (4-1). These compounds are known. In the parentheses after the melting points, the publications showing the manufacturing process are listed. (4-2) 5-(2-n-Butyloxalylaminophenyl)tetrazole Melting point: 132 ∼ 137°C (J.P. Kokoku No. 59-1704) (4-3) 5-(4-Chloro-3,5-diethyloxalylaminophenyl)tetrazole Melting point: 214 ∼ 215.5°C (decomposition) (J.P. Kokoku No. 59-1704) (4-4) 5-(4-Chloro-3,5-di-n-butyloxalylaminophenyl)tetrazole Melting point: 217 ∼ 218°C (J.P. Kokoku No. 59-1707) (4-5) 5-(3-Ethyloxalylaminophenyl)tetrazole Melting point: 193 ∼ 195°C (J.P. Kokoku No. 59-1705) Example 5 (Reaction 5) (5-1) 3-(1H-Tetrazol-5-yl)oxanilic acid Five grams of the compound obtained from Example 4 (4-5), namely 5-(3-ethyloxalylaminophenyl)tetrazole or ethyl 3-(1H-tetrazol-5-yl) oxanilate, were dissolved in 35 ml of ethanol. Sodium hydroxide solution (0.5 N, 100 ml) was dropwise added to the solution, while cooling them with water. After the addition, the temperature was gradually raised and the reaction was conducted at room temperature for 3 hr. The resultant solution was dropwise added to 70 ml of 4 N hydrochloric acid at room temperature. After the addition, the mixture was stirred for 1 hr and then the precipitated crystals were filtered. The crystals were washed with water, to give 3.9 g of 3-(1H-tetrazol-5-yl)oxanilic acid (yield: 87.4%). The crystals were further recrystallized from isopropyl alcohol-water. Melting point: 241 ∼ 243°C (decomposition) (J.P. Kokai No. 63-44570) Experiment 1 Aldose Reductase Inhibition Test (1) Test Procedure Six-week-old male SD rats were killed under ether anesthesia and their crystalline lenses were immediately removed and stored at -80°C. The lenses were homogenized in 3 volumes of 135 mM sodium potassium phosphate buffer (pH: 7.0) and centrifuged at a rate of 30,000 rpm for 30 min. The supernatant was dialyzed overnight against 0.05 M sodium chloride, to produce an aldose reductase solution. All operations were conducted at 4°C . The enzyme solution was stored at -80 °C. The activity of aldose reductase was determined according to a slight modification of the method of J.H. Kinoshita et al [J. Biol. Chem., 240, 877 (1965)]. Namely, 0.1 ml of DL-glycerine aldehyde (final concentration: 10 mM) was added to 0.9 ml of 100 mM sodium potassium phosphate buffer (pH 6.2) which contained lithium sulfate (final concentration: 400 mM), reduced nicotinamide adenine dinucleotide phosphate (final concentration: 0.15 mM), the enzyme solution, and the compound to be tested (final concentration: 5 × 10⁻⁵ M or 10⁻⁶ M), and then the reaction was conducted at 30°C for 5 min. During this reaction, the absorbance at 340 nm was observed with the lapse of time. The maximum reducing rate of the absorbance (U) during the reaction was determined. By subtracting, from this value, the maximum reducing rate (U₀) at 340 nm of the reaction solution before the addition of the substrate (DL-glycerine aldehyde), the reaction rate (V) ( V=U-U₀ ) was calculated as a true reaction rate in the presence of the compound to be tested. The same procedure was repeated except for the absence of the compound to be tested. A true reaction rate (V₀) in case the enzyme was not inhibited was calculated ( V₀=U'-U₀' ). The inhibitory activity of aldose reductase was determined by the following formula. (2) Results The results of Experiment 1 are shown in table 5. The results show that the present compounds provide excellent aldose reductase inhibitory activity at a concentration of 5 × 10⁻⁵ M or 1 × 10⁻⁶ M . Experiment 2 (1) Test Procedure In the same manner as Experiment 1, the inhibitions at final concentrations of 10⁻⁶ , 10⁻⁷ and 10 ⁻⁸ M for the compound to be tested were calculated. Based on these values, a concentration for inhibiting the aldose reductase activity by 50% (IC₅₀ (M)) was calculated. As a control, the same experiment was conducted for the known aldose reductase inhibitor, ONO-2235[(E)-3-carboxymethyl-5-[(2E)-methyl-3-phenylpropenylidene]rhodanine]. (2) Results The results are shown in Table 6 below. It is apparent that the present compounds provide aldose redinctase inhibitory activity which are equivalent or superior to that of the known aldose reductase inhibitor (ONO-2235). Experiment 3 (Acute Toxicity Test) (1) Test Procedure The compound listed in Table 7 and suspended in 0.5% sodium carboxymethyl cellulose was orally administered to male MCH mice (6 weeks old; 5 animals per test group). The symptom of these test animals was observed for 14 days after the administration and LD₅₀ was estimated from the number of animals died during this term. During the test, the mice were able to take food and water freely. (2) Results The results are shown in Table 7. LD₅₀ for each of the compounds is above 3,000 mg/kg.

Claims: A compound of the general formula [I] wherein R₁ is -A-COOR₅ (A is an alkylene group having 1 to 4 carbon atoms and R₅ is a hydrogen atom or a lower alkyl group), and R₂, R₃ and R₄ are the same as or different from each other and selected from the group consisting of a hydrogen atom, a hydroxy group, a halogen atom, a carboxyl group, an alkyl group, an amide group, an amino group, an alkoxy group, an aryl group, an aryloxy group, an alkylthio group, an alkylsulfinyl group, an alkylsulfonyl group, a nitro group, - NHCOCOOR₆ (R₆ is a hydrogen atom or a lower alkyl group), a mono- or dialkylaminosulfonyl group, and a residual group having the following formula: (A and R₅ are the same as in the above), with the proviso that when A is -C(CH₃)₂- or -(CH₂)₂- and R₅ is a hydrogen atom or an ethyl group, or A is -CH₂- and R₅ is a hydrogen atom, a methyl group or an ethyl group, or A is -(CH₂)₃- or -(CH₂)₄- and R₅ is a hydrogen atom or a methyl group then R₂, R₃, and R₄ are not all hydrogen atoms, and when R₄ is 3- or 4-bromine, 3-or 4-chlorine, 3- or 4-nitro, 3- or 4-methyl or 3-trifluoromethyl then R₂ and R₃ are not simultaneously a hydrogen atom, A is not -CH₂- and R₅ is not a hydrogen atom nor an ethyl group. A pharmaceutical composition containing a compound of Claim 1 and optionally a pharmaceutically acceptable carrier and/or diluent. The composition of Claim 2 for the inhibition of aldose reductase. The composition of Claim 2 for the treatment of diabetic complications. The composition of any of Claims 2 to 4 wherein the compound of formula [I] is envisaged to be administered in an amount of 1 to 1000 mg per adult. The composition of any of Claims 2 to 5 wherein the administration is to be made by oral administration, intravenous injection, subcutaneous injection, intramuscular injection, or local medication. Use of a compound of the general formula [I] wherein R₁ is a hydrogen atom or -A-COOR₅ and A, R₂, R₃, R₄ and R₅ are as defined in Claim 1 for the preparation of a pharmaceutical composition for the inhibition of aldose reductase. Use of a compound of the general formula [I] wherein R₁ is a hydrogen atom or -A-COOR₅ and A, R₂, R₃, R₄ and R₅ are as defined in Claim 1 for the preparation of a pharmaceutical composition for the treatment of diabetic complications. Use according to Claims 7 or 8 wherein the compound of the general formula [I] is envisaged to be administered in an amount of 1 to 1000 mg per adult. Use according to any of Claims 7 to 9 wherein the administration is to be made by oral administration, intravenous injection, subcutaneous injection, intramuscular injection, or local medication.

Inventors: AGATA MITSUZI, AKIBA KIYOSHI, GOTO MASAYOSHI, HORIO YOSHIHIRO, INUKAI SINJI, OHMURA TAKEO, OOTAKE YASUHIRO, SAWAKI SHOHEI, AGATA, MITSUZI, AKIBA, KIYOSHI, GOTO, MASAYOSHI, HORIO, YOSHIHIRO, INUKAI, SINJI, OHMURA, TAKEO, OOTAKE, YASUHIRO, SAWAKI, SHOHEI
Applicants: WAKAMOTO PHARMA CO LTD, WAKAMOTO PHARMACEUTICAL CO., LTD.
Application year: 1990
Main classification: C07D257
IPC codes: C07D257