4-ACETYLAMINO-3-METHYLBENZOIC ACID COMPOUND, ITS PRODUCTION AND PRODUCTION OF 1H-INDAZOLE-5-CARBOXYLIC ACID USING THE SAME

摘要

PROBLEM TO BE SOLVED: To obtain 4-acetylamino-3-methylbenzoic acid as an intermediate for 1H-indazole-5-carboxylic acid, by reducing 3-methyl-4-nitrobenzoic acid and reacting the reduced compound with acetic anhydride in an organic solvent. SOLUTION: A 3-methyl-4-nitrobenzoic acid compound of formula II (R<1> is H or a l-5C alkyl) is reduced to give a 4-amino-3-methylbenzoic acid compound of formula III (R<1> is as shown above), which is reacted with acetic anhydride in an organic solvent to form a 4-acetylamino-3-methylbenzoic acid of formula I (R<1> is as shown above). Further the compound of formula I is reacted with a nitrite in an organic solvent in the presence of acetic anhydride and a phase transfer catalyst to give a l-acetyl-5-carboxyindazole, which is hydrolyzed to give a 1H-indazole-5-carboxylic acid.