Pure 5,6-alkylenedioxy-2-chloro-benzimidazole preparation in high yield, for use as intermediate for microbicides, especially fungicides, by chlorinating corresponding thione with chlorine in organic diluent

摘要

Preparation of 5,6-alkylenedioxy-2-chloro-benzimidazoles (I) involves reacting a 5,6-alkylenedioxy-1,3-dihydro-benzimidazole-2-thione (II) with chlorine, in presence of an organic diluent and optionally dilute aqueous hydrochloric acid, at -10 to +50 [deg] C. Preparation of 2-chloro-benzimidazole derivatives of formula (I) involves reacting a 1,3-dihydro-benzimidazole thione of formula (II) with chlorine, in presence of an organic diluent and optionally dilute aqueous hydrochloric acid, at -10 to +50 [deg] C. [Image] A : optionally halogenated 1-2C alkylene.