Thiabendazole → 1-(3-Hexyloxycarbonyl)-2-(4-thiazolyl)-benzimidazole

Participants

Reaction Steps

28.3 G. (0.172 moles) of 3-hexyl chloroformate is added dropwise with protection from moisture to a stirred suspension of 33.1 g. (0.165 moles) of 2-(4-thiazolyl)-benzimidazole in 200 ml. of anhydrous pyridine. The 3-hexyl chloroformate is added over a period of 20 minutes during which time the reaction mixture initially becomes a clear solution followed by the precipitation of pyridine hydrochloride. The reaction mixture is stirred overnight at room temperature filtered to remove pyridine hydrochloride which is washed with some additional anhydrous pyridine and the combined filtrates and washings evaporated to dryness in vacuo. An oil is obtained which is dissolved in 300 ml. of methylene chloride and filtered. The filtrate is washed twice with a 250 ml. of 0.25 N-hydrochloric acid containing ice followed by a washing with 200 ml. of saturated sodium bicarbonate solution. The methylenechloride is dried, treated with charcoal, filtered and evaporated to dryness in vacuo affording 39.2 g. of an orange oil which solidified on standing. The solid material is recrystallized from hexane affording 33.5 g. (62%) of 1-(3-hexyloxycarbonyl)-2-(4-thiazolyl)-benzimidazole melting point 79.5 to 81° C.

Provenance & Evidence