Preparation of pure 3,4-dichloro-N-(2-cyanophenyl)-5-isothiazole-carboxamide, for use as microbicide, comprises N-acylating anthranilamide then dehydration in methyl or ethyl acetate diluent

摘要

3,4-Dichloro-N-(2-cyanophenyl)-5-isothiazole-carboxamide (I) is prepared by (a) reacting 3,4-isothiazole-5-carbonyl chloride (II) with anthanilamide (III) and (b) dehydrating the obtained amide (IV), where (i) at least step (a) is carried out in presence of methyl and/or ethyl acetate as diluent and/or (ii) the product of step (b) is worked up and isolated in presence of an alcohol. Preparation of 3,4-dichloro-N-(2-cyanophenyl)-5-isothiazole-carboxamide of formula (I) involves (a) reacting 3,4-isothiazole-5-carbonyl chloride of formula (II) with anthanilamide of formula (III), optionally in presence of acid acceptor, and (b) reacting the obtained N-(2-(aminocarbonyl)-phenyl)-3,4-dichloro-5-isothiazole-carboxamide of formula (IV) with a dehydrating agent, where (i) at least step (a) is carried out in presence of methyl acetate and/or ethyl acetate as diluent and/or (ii) the product of step (b) is worked up and isolated in presence of an alcohol. [Image] [Image] [Image] ACTIVITY : Antibacterial. MECHANISM OF ACTION : None given.