Method for producing 1,2-benzisothiazol-3-ones

Abstract: A method for producing a 1,2-benzisothiazol-3-one, having the steps of carrying out a reaction of a 2-(alkylthio)benzaldehyde with a hydroxylamine to give a 2-(alkylthio)benzaldehyde oxime and carrying out a reaction of the 2-(alkylthio)benzaldehyde oxime with a halogenating agent; and a method for producing a 1,2-benzisothiazol-3-one, having the steps of carrying out a reaction of a 2-halobenzonitrile with an alkanethiol in a heterogeneous solvent system in the presence of a base to give a 2-(alkylthio)benzonitrile and carrying out a reaction of the 2-(alkylthio)benzonitrile with an halogenating agent in the presence of water.

Description: BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a novel method for producing 1,2-benzisothiazol-3-ones, using 2-(alkylthio)benzaldehydes or 2-(alkylthio)benzaldehyde oximes as starting materials. 1,2-benzisothiazol-3-ones are compounds useful as antibacterial agents and antifungal agents. Discussion of the Related Art The following methods are known for producing 1,2-benzisothiazol-3-ones. (A) Bull. Chem. Soc. Jpn., 55, 1183-1187 (1982) In this method, 2-(methylthio)benzamide is produced from 2-(methylthio)benzoyl chloride; oxidized with periodic acid to 2-(methylsulfinyl)benzamide; and cyclized in the presence of thionyl chloride to yield a 1,2-benzisothiazol-3-one. (B) Org. Prep. Proced. Int., 15, 315-319(1983) In this method, a 1,2-benzisothiazol-3-one is obtained in 4 steps, using thiosalicylic acid as a starting material. (C) Ger. Offen. 3500577 (1986) In this method, a desired 1,2-benzisothiazol-3-one is obtained using thiosalicylic acid as a starting material and sodium hydroxide in the final cyclization process. The present applicant have filed patent applications for the following methods as modified methods of the above known methods. (D) Japanese Patent Application No. 5-350932 titled "A method for producing 1,2-benzisothiazol-3-ones" filed on December 29, 1993. (E) Japanese Patent Application No. 6-151476 titled " A method for producing isothiazolone derivatives" filed on June 8, 1994. However, the above known conventional methods have the following drawbacks: In Method (A), the starting 2-(methylthio)benzoyl chloride has problems of high production cost and poor stability. This method also requires the use of an expensive periodic acid which is dangerous in handling and involves many reaction steps. Methods (B) and (C) require the use of expensive thiosalicylic acid as the starting material and involve many reaction steps. Therefore, this method is not satisfactory for industrial use. Methods (D) and (E) proposed by the present applicant are modifications of the above conventional methods, where a starting 2-(alkylthio)benzamide reacts with a halogenating agent. As stated above, all known methods are not satisfactory for production on an industrial scale. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a simple and economical method for producing 1,2-benzisothiazol-3-ones on an industrial scale, without using materials which are costly and dangerous in handling. In order to achieve the above objects, the present inventors made intensive studies to provide an easy and economically advantageous method for producing 1,2-benzisothiazol-3-ones without using materials which are costly and dangerous in handling. As a result, the inventors found that a 1,2-benzisothiazol-3-one represented by the general formula (III) can be obtained by treating a 2-(alkylthio)benzaldehyde oxime represented by the general formula (II) with a halogenating agent, the 2-(alkylthio)benzaldehyde oxime being obtained by the reaction of a 2-(alkylthio)benzaldehyde represented by the general formula (I) with a hydroxylamine. wherein R 1 represents an alkyl group having 1 to 4 carbon atoms, and R 2 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a nitro group, a carboxyl group or an ester thereof, or a halogen atom. Specifically, the present inventors noted that a 2-(alkylthio)benzaldehyde oxime represented by the general formula (II) is easily obtained by the reaction of a 2-(alkylthio)benzaldehyde represented by the general formula (I) with a hydroxylamine, and have found that a 1,2-benzisothiazol-3-one represented by the general formula (III) is obtained by further treating with a halogenating agent the 2-(alkylthio)benzaldehyde oxime represented by the general formula (II) obtained by the above reaction. The present inventors have also found that the series of the above reactions can be carried out as a one-pot process when a water-insoluble organic solvent system is used. Based upon the above findings, the present inventors made further studies and have completed the present invention. In brief, the present invention is concerned with: (1) A method for producing a 1,2-benzisothiazol-3-one represented by the general formula (III), comprising carrying out a reaction of a 2-(alkylthio)benzaldehyde represented by the following general formula (I): wherein R 1 represents an alkyl group having 1 to 4 carbon atoms, and R 2 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a nitro group, a carboxyl group or an ester thereof, or a halogen atom, with a hydroxylamine to give a 2-(alkylthio)benzaldehyde oxime represented by the following general formula (II): wherein R 1 and R 2 are defined as above; and carrying out a reaction of said 2-(alkylthio)benzaldehyde oxime with a halogenating agent to give a 1,2-benzisothiazol-3-one represented by the following general formula (III): wherein R 2 is defined as above; (2) A method for producing a 1,2-benzisothiazol-3-one represented by the general formula (III), comprising carrying out a reaction of a 2-(alkylthio)benzaldehyde oxime represented by the following general formula (II): wherein R 1 represents an alkyl group having 1 to 4 carbon atoms, and R 2 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a nitro group, a carboxyl group or an ester thereof, or a halogen atom, with a halogenating agent to give a 1,2-benzisothiazol-3-one represented by the following general formula (III): wherein R 2 is defined as above; According to the process of the present invention, 1,2-benzisothiazol-3-ones, compounds useful as antibacterial or antifungal agents, can easily be produced in high yield in short process without using expensive starting materials. DETAILED DESCRIPTION OF THE INVENTION The present invention will be explained in detail below by explaining the following two embodiments of the present invention: Embodiment I: A method for producing a 1,2-benzisothiazol-3-one by treating with a halogenating agent a 2-(alkylthio)benzaldehyde oxime represented by the general formula (II) that is obtained by the reaction between a 2-(alkylthio)benzaldehyde represented by the general formula (I) and a hydroxylamine. Embodiment I The feature of Embodiment I of the present invention is in that a 1,2-benzisothiazol-3-one is produced by simple procedures where a 2-(alkylthio)benzaldehyde oxime that can readily be obtained from a 2-(alkylthio)benzaldehyde is cyclized by the action of a halogenating agent. Another feature of this embodiment lies in that a 1,2-benzisothiazol-3-one can efficiently and easily be produced in a one-pot process where a 2-(alkylthio)benzaldehyde is treated with a hydroxylamine to yield a 2-(alkylthio)benzaldehyde oxime in a water-insoluble organic solvent; the solvent layer containing the oxime is separated; and a halogenating agent is added to the solvent to yield a 1,2-benzisothiazol-3-one. R 1 in the above general formulas (I) and (II) stands for an alkyl group having 1 to 4 carbon atoms. Alkyl groups represented by R 1 are exemplified by methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl groups, with a preference given to methyl, ethyl, n-propyl, and tert-butyl groups. R 2 in the general formulas (I), (II), and (III) stands for a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a nitro group, a carboxyl group or an ester thereof, or a halogen atom. Alkyl groups represented by R 2 are exemplified by methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups. Alkoxy groups represented by R 2 are exemplified by methoxy, ethoxy, propoxy, and butoxy groups. Esters of carboxyl group represented by R 2 are exemplified by methoxy carbonyl, ethoxy carbonyl, propoxy carbonyl, and butoxy carbonyl. Halogen atoms represented by R 2 are exemplified by a chlorine atom and a bromine atom. Preferred examples of R 2 include a hydrogen atom, a chlorine atom, and a nitro group. In the present method, an oxime is first formed by treating an 2-(alkylthio)benzaldehyde represented by the general formula (I) with hydroxylamine to yield a 2-(alkylthio)benzaldehyde oxime represented by the general formula (II). Examples of 2-(alkylthio)benzaldehyde represented by the general formula (I) include: 2-(methylthio)benzaldehyde, 2-(ethylthio)benzaldehyde, 2-(n-propylthio)benzaldehyde, 2-(tert-butylthio)benzaldehyde, 3-methyl-2-(methylthio)benzaldehyde, 5-butyl-2-(methylthio)benzaldehyde, 4-methoxy-2-(methylthio)benzaldehyde, 2-methylthio-3-nitrobenzaldehyde, 4-chloro-2-(methylthio)benzaldehyde, 4-carboxy-2-(methylthio)benzaldehyde, and 4-methoxycarbonyl-2-(methylthio)benzaldehyde. Among the above examples, 2-(methylthio)benzaldehyde, 2-(ethylthio)benzaldehyde, 2-(n-propylthio)benzaldehyde, and 2-(tert-butylthio)benzaldehyde are preferably used because they are readily available and can give products with high antibacterial activity. Practically, hydroxylamines used in the present invention are supplied as mineral acid salts such as sulfates. Therefore, upon the reaction with 2-(alkylthio)benzaldehyde, the salt of hydroxylamine is neutralized with a base to release a free hydroxylamine in the solvent system. Mineral acid salts of hydroxylamines usable in the present invention include hydrochloric acid salts and sulfates, with a preference given to sulfates from the economical viewpoint. The hydroxylamine mineral acid salt is used normally in an amount of 0.8 to 3.0 moles, preferably 1.0 to 2.0 moles, per mole of 2-(alkylthio)benzaldehyde. When the amount of the salt is less than 0.8 moles, the amount of unchanged 2-(alkylthio)benzaldehyde tends to increase. On the other hand, even when the amount of the salt exceeds 3.0 moles, any extra effects cannot be obtained. Examples of the base used for neutralizing the hydroxylamine mineral acid salt used in oxime formation process include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkali metal carbonates such as sodium carbonate and potassium carbonate; and metal alcoholates such as sodium methylate and sodium ethylate. Of these, sodium carbonate is preferably used in view of yield and cost. The above-mentioned base is used in an adequate amount to neutralize the hydroxylamine mineral acid salt. Specifically, the amount of the base is 0.8 to 1.5 equivalents of the acid component of the hydroxylamine mineral acid salt. When the amount of the base is less than 0.8 equivalents of the acid component of the salt, the amount of unchanged 2-(alkylthio)benzaldehyde increases. On the other hand, even when the amount of the base exceeds 1.5 equivalents, any extra effects cannot be obtained, and, therefore, it is economically disadvantageous. The reaction solvents used for the oxime formation process are not particularly limited as long as they are inert to the reaction. Examples of water-insoluble solvents include hydrocarbons, such as n-hexane, n-heptane, cyclohexane, methylcyclohexane, benzene, toluene and xylene; and halogenated hydrocarbons, such as methylene chloride, 1,2-dichloroethane and chlorobenzene. Examples of water-soluble solvents include alcohols, such as methanol, and ethanol. Of the above solvents, a water-insoluble solvent allows to carry out the oxime formation reaction and the subsequent reaction of the resulting oxime with a halogenating agent in a one-pot process, and to facilitate the production of 1,2-benzisothiazol-3-one. The amount of the solvent is normally 1 to 30 times the weight of 2-(alkylthio)benzaldehyde. The reaction temperature for the oxime formation is normally in the range of from -20 to 100°C, preferably 0 to 80°C. Reaction temperatures higher than 100°C cause problems of side reactions. On the other hand, reaction rate lowers to an impractical level when the reaction temperature is less than -20°C. The reaction time varies with the reaction temperature and the type of reaction solvent, and it is normally in the range between 1 and 40 hours. A 2-(alkylthio)benzaldehyde oxime can be isolated and purified from the reaction mixture by a conventional method, i.e., by direct crystallization or by extraction and subsequent recrystallization. Also, the 2-(alkylthio)benzaldehyde oxime dissolved in the reaction solvent obtained by the above-mentioned method can directly be used as a starting material for the cyclization to yield a 1,2-benzisothiazol-3-one without being isolated and purified. Next, a 2-(alkylthio)benzaldehyde oxime represented by the general formula (II) obtained by the above process is treated with a halogenating agent to yield a 1,2-benzothiazol-3-one represented by the general formula (III). This process hereinafter is referred to as a cyclization process. Examples of 2-(alkylthio)benzaldehyde oximes represented by the general formula (II) include: 2-(methylthio)benzaldehyde oxime, 2-(ethylthio)benzaldehyde oxime, 2-(n-propylthio)benzaldehyde oxime, 2-(tert-butylthio)benzaldehyde oxime, 3-methyl-2-(methylthio)benzaldehyde oxime, 5-butyl-2-(methylthio)benzaldehyde oxime, 4-methoxy-2-(methylthio)benzaldehyde oxime, 2-methylthio-3-nitrobenzaldehyde oxime, 4-chloro-2-(methylthio)benzaldehyde oxime, 4-carboxy-2-(methylthio)benzaldehyde oxime, and 4-methoxycarbonyl-2-(methylthio)benzaldehyde oxime. Among the above examples, 2-(methylthio)benzaldehyde oxime, 2-(ethylthio)benzaldehyde oxime, 2-(n-propylthio)benzaldehyde oxime, and 2-(tert-butylthio)benzaldehyde oxime are preferably used because they are readily available and can give products with high antibacterial activity. Examples of halogenating agents usable in the present invention include chlorine, bromine, sulfuryl chloride and sulfuryl bromide, with a preference given to chlorine, bromine, and sulfuryl chloride from the economical viewpoint. The halogenating agent is used normally in an amount of 0.8 to 3.0 moles, preferably 1.0 to 2.0 moles, per mole of 2-(alkylthio)benzaldehyde oxime. When the amount of the halogenating agent is less than 0.8 moles, the amount of unchanged 2-(alkylthio)benzaldehyde oxime tends to increase. On the other hand, even when the amount of the halogenating agent exceeds 3.0 moles, the yield tends to decrease due to the side reaction. The reaction solvents used in the cyclization process above are not particularly limited as long as they are inert to the reaction. However, when a 1,2-benzisothiazol-3-one is obtained in a one-pot process, it is preferable to use the same reaction solvent as used in the oxime formation reaction. Examples of the solvents include hydrocarbons, such as n-hexane, n-heptane, cyclohexane, methylcyclohexane, benzene, toluene and xylene; and halogenated hydrocarbons, such as methylene chloride, 1,2-dichloroethane and chlorobenzene, with a preference given to monochlorobenzene and toluene. The amount of the solvent is normally 1 to 30 times the weight of 2-(alkylthio)benzaldehyde oxime. The reaction temperature for the cyclization is normally in the range of from -20 to 170°C, preferably 0 to 150°C. Reaction temperatures higher than 170°C cause problems of side reactions. On the other hand, reaction rate lowers to an impractical level when the reaction temperature is less than -20°C. The reaction time varies with the reaction temperature and the type of reaction solvent, and it is normally in the range between 1 and 40 hours. A desired 1,2-benzisothiazol-3-one can be isolated and purified from the reaction mixture by a conventional method such as direct crystallization, and extraction followed by recrystallization. But other methods may also be used with no limitation. The isolation of 1,2-benzisothiazol-3-one from the reaction mixture obtained by the above method can normally be carried out by conventional crystallization technique or by recrystallization after extraction, but other technique may be used. Examples of 1,2-benzisothiazol-3-ones represented by the general formula (III) obtained by the method in Embodiment I of the present invention includes: 1,2-benzisothiazol-3-one, 7-methyl-1,2-benzisothiazol-3-one, 5-butyl-1,2-benzisothiazol-3-one, 6-methoxy-1,2-benzisothiazol-3-one, 7-nitro-1,2-benzisothiazol-3-one, 6-chloro-1,2-benzisothiazol-3-one, 6-carboxy-1,2-benzisothiazol-3-one, and 6-methoxycarbonyl-1,2-benzisothiazol-3-one. EXAMPLES The present invention will be further described by means of the following working examples, without intending to restrict the scope of the present invention thereto. Incidentally, the obtained product is confirmed by nuclear magnetic resonance method ( 1 H-NMR) or mass spectroscopy in order to determine whether a desired product is obtained. Example 1: Synthesis of 1,2-benzisothiazol-3-one from 2-(methylthio)benzaldehyde in a one-pot process To a 500 ml four-necked flask equipped with a stirrer, a thermometer, and a condenser, 38.0 g (0.25 mol) of 2-(methylthio)benzaldehyde, 150 g of monochlorobenzene, and 91.7 g (0.275 mol) of 24.6% aqueous solution of hydroxylamine-1/2 sulfate were placed. To the above mixture in the flask, 51.2 g (0.145 mol) of 30% aqueous solution of sodium carbonate was added dropwise while stirring at a temperature of from 20 to 25°C and allowed to react for 2 hours at the same temperature. After the completion of the reaction, the reaction mixture was heated to a temperature of from 40 to 50°C to separate to monochlorobenzene layer and water layer. The lower water layer was discarded. The monochlorobenzene layer contained 40.9 g of 2-(methylthio)benzaldehyde oxime. The yield was 98% against 2-(methylthio)benzaldehyde. Into the monochlorobenzene layer, 22.6 g (0.32 mol) of chlorine was introduced with stirring at a temperature of from 10 to 20°C and allowed to react at a temperature of from 90 to 100°C for 1 hour. After the completion of the reaction, the reaction mixture was cooled to room temperature to precipitate white crystals. The white crystals were washed with monochlorobenzene, and dried to give 34.0 g of 1,2-benzisothiazol-3-one (melting point: 157 to 158°C). The yield of the product was 92% against 2-(methylthio)benzaldehyde oxime, and 90% against 2-(methylthio)benzaldehyde. Example 2: Synthesis of 1,2-benzisothiazol-3-one from 2-(methylthio)benzaldehyde oxime The monochlorobenzene layer obtained by the same procedures as in Example 1 was condensed to precipitate crystals. The crystals were filtered and dried to isolate a 2-(methylthio)benzaldehyde oxime (melting point: 88 to 89°C). 39.7 g of the oxime isolated was dissolved in 200 g of toluene. Then, chlorine was introduced into the mixture to react with the oxime to yield 32.7 g of 1,2-benzisothiazol-3-one. The yield against 2-(methylthio)benzaldehyde oxime was 91%. Example 3: Synthesis of 1,2-benzisothiazol-3-one from 2-(methylthio)benzaldehyde oxime From the monochlorobenzene layer obtained by the same procedures as in Example 1,2-(methylthio)benzaldehyde oxime was isolated in the same manner as in Example 2. 39.7 g of the oxime isolated was dissolved in 150 g of monochlorobenzene. Then, the oxime was cyclized in the same manner as in Example 1 except that chlorine was changed to 35.3 g (0.26 mol) of sulfuryl chloride. As a result, 32.7 g of 1,2-benzisothiazol-3-one was obtained. The yield against 2-(methylthio)benzaldehyde oxime was 91%. Example 4: Synthesis of 1,2-benzisothiazol-3-one from 2-(methylthio)benzaldehyde oxime From the monochlorobenzene layer obtained by the same procedures as in Example 1, 2-(methylthio)benzaldehyde oxime was isolated in the same manner as in Example 2. 39.7 g of the oxime isolated was dissolved in 150 g of monochlorobenzene. Then, the oxime was cyclized in the same manner as in Example 1 except that blowing of chlorine was changed to dropping of 49.3 g (0.31 mol) of bromine. As a result, 32.3 g of 1,2-benzisothiazol-3-one was obtained. The yield against 2-(methylthio)benzaldehyde oxime was 90%. Example 5: Synthesis of 1,2-benzisothiazol-3-one from 2-(methylthio)benzaldehyde in one-pot process To a 500 ml four-necked flask equipped with a stirrer, a thermometer, and a condenser, 38.0 g (0.25 mol) of 2-(methylthio)benzaldehyde, 200 g of toluene, and 91.7 g (0.275 mol) of 24.6% aqueous solution of hydroxylamine-1/2 sulfate were placed. To the above mixture in the flask, 51.2 g (0.145 mol) of 30% aqueous solution of sodium carbonate was added dropwise while stirring at a temperature of from 20 to 25°C and allowed to react for 2 hours at the same temperature. After the completion of the reaction, the reaction mixture was heated to a temperature of from 40 to 50°C to separate to toluene layer and water layer. The lower water layer was discarded. The upper toluene layer contained 40.9 g of 2-(methylthio)benzaldehyde oxime. The yield was 98% against 2-(methylthio)benzaldehyde. To the toluene layer, 36.4 g (0.27 mol) of sulfuryl chloride was added dropwise with stirring at a temperature of from 10 to 20°C, and allowed to react at a temperature of from 90 to 100°C for 1 hour. After the completion of the reaction, the reaction mixture was cooled to room temperature to precipitate white crystals. The white crystals were washed with toluene, and dried to give 33.7 g of 1,2-benzisothiazol-3-one (melting point: 157 to 158°C). The yield of the product was 91% against 2-(methylthio)benzaldehyde oxime, and 89% against 2-(methylthio)benzaldehyde. Example 6: Synthesis of 6-chloro-1,2-benzisothiazol-3-one from 4-chloro-2-(methylthio)benzaldehyde in one-pot process An oxime formation reaction was carried out in the same manner as in Example 1 except that 46.6 g (0.25 mol) of 4-chloro-2-(methylthio)benzaldehyde was used in place of 2-(methylthio)benzaldehyde. The upper monochlorobenzene layer contained 49.4 g of 4-chloro-2-(methylthio)benzaldehyde oxime. The yield was 98% against 4-chloro-2-(methylthio)benzaldehyde. Into the monochlorobenzene layer, 22.6 g (0.32 mol) of chlorine was introduced with stirring at a temperature of from 5 to 15°C, and allowed to react at a temperature of from 90 to 100°C for 1 hour. After the completion of the reaction, the reaction mixture was cooled to room temperature to precipitate white crystals. The white crystals were washed with monochlorobenzene, and dried to give 40.9 g of 6-chloro-1,2-benzisothiazol-3-one (melting point: 271 to 272°C). The yield of the product was 90% against 4-chloro-2-(methylthio)benzaldehyde oxime, and 88% against 4-chloro-2-(methylthio)benzaldehyde.

Claims: A method for producing a 1,2-benzisothiazol-3-one represented by the general formula (III), comprising carrying out a reaction of a 2-(alkylthio)benzaldehyde represented by the following general formula (I): wherein R 1 represents an alkyl group having 1 to 4 carbon atoms, and R 2 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a nitro group, a carboxyl group or an ester thereof, or a halogen atom, with a hydroxylamine to give a 2-(alkylthio)benzaldehyde oxime represented by the following general formula (II): wherein R 1 and R 2 are defined as above; and carrying out a reaction of said 2-(alkylthio)benzaldehyde oxime with a halogenating agent to give a 1,2-benzisothiazol-3-one represented by the following general formula (III): wherein R 2 is defined as above. The method according to claim 1, wherein the reactions are carried out in a water-insoluble organic solvent in a one-pot process. The method according to claim 2, wherein said water-insoluble organic solvent is monochlorobenzene or toluene. The method according to any one of claims 1 to 3, wherein said halogenating agent is chlorine or bromine. The method according to any one of claims 1 to 3, wherein said halogenating agent is sulfuryl chloride. The method according to any one of claims 1 to 5, wherein the compound represented by the general formula (I) is selected from the group consisting of 2-(methylthio)benzaldehyde, 2-(ethylthio)benzaldehyde, 2-(n-propylthio)benzaldehyde, 2-(tert-butylthio)benzaldehyde, 3-methyl-2-(methylthio)benzaldehyde, 5-butyl-2-(methylthio)benzaldehyde, 4-methoxy-2-(methylthio)benzaldehyde, 2-methylthio-3-nitrobenzaldehyde, 4-chloro-2-(methylthio)benzaldehyde, 4-carboxy-2-(methylthio)benzaldehyde, and 4-methoxycarbonyl-2-(methylthio)benzaldehyde. A method for producing a 1,2-benzisothiazol-3-one represented by the general formula (III), comprising carrying out a reaction of a 2-(alkylthio)benzaldehyde oxime represented by the following general formula (II): wherein R 1 represents an alkyl group having 1 to 4 carbon atoms, and R 2 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a nitro group, a carboxyl group or an ester thereof, or a halogen atom, with a halogenating agent to give a 1,2-benzisothiazol-3-one represented by the following general formula (III): wherein R 2 is defined as above. The method according to claim 7, wherein said halogenating agent is chlorine or bromine. The method according to claim 7, wherein said halogenating agent is sulfuryl chloride. The method according to any one of claims 7 to 9, wherein the compound represented by the general formula (II) is 2-(methylthio)benzaldehyde oxime.

Inventors: GODA HIROSHI, KAGANO HIROKAZU, SAKAUE SHIGEKI, YAMAMOTO MIKIO, YOSHIDA KATSUHIKO, GODA, HIROSHI, KAGANO, HIROKAZU, SAKAUE, SHIGEKI, YAMAMOTO, MIKIO, YOSHIDA, KATSUHIKO, Goda, Hiroshi, c/o Sumitomo Seika Chem. Co.Ltd., Kagano, Hirokazu, c/o Sumitomo Seika Chem. Co.Ltd., Sakaue, Shigeki, Sumitomo Seika Chem. Co.Ltd., Yamamoto, Mikio, Sumitomo Seika Chem. Co.Ltd., Yoshida, Katsuhiko, Sumitomo Seika Chem. Co.Ltd.
Applicants: SUMITOMO SEIKA CHEMICALS, SUMITOMO SEIKA CHEMICALS CO., LTD.
Application year: 1995
Main classification: C07D275
IPC codes: C07D275