To obtain the subject compound in good yield at a low cost by carrying out the diazotization and mercaptide reaction of a 2-amino-3-nitrobenzoic acid derivative as a starting raw material.
A 2-amino-3-nitrobenzoic acid derivative represented by formula I (R1 is H or a 1-4C alkyl) is diazotized and then reacted with a mercaptide represented by the formula R2SM [R2 is a 1-16C alkyl or benzyl; M is an alkali(ne earth) metal] to afford a 2-substituted-3-nitrobenzoic acid derivative represented by formula II. The resultant compound is further reduced to provide a 2-substituted-3-aminobenzoic acid derivative represented by formula III. The compound represented by formula I is diazotized and then reacted with a mercapto forming agent and, as necessary, hydrolyzed and reduced to thereby afford a 2-mercapto-3-aminobenzoic acid derivative represented by formula IV. The compound represented by formula III is useful as a synthetic intermediate for an agrochemical intermediate 1,2,3-benzothiadiazole-7-carboxylic acid.
YOSHIDA KATSUHIKO
ITSUDA HIROSHI
