Hydrochloric Acid → ST50143142

Participants

Reaction Steps

2-Mercaptobenzimidazole (14.6 g, 0.1 mole) and chloroacetone (9.25 g, 0.1 mole) were added to 2-butanone (400 ml) and refluxed for 5 hrs. On cooling the product hydrochloride, 21.24 g, 88% was isolated by filtration, washed with acetone and air dried. The salt was dissolved in water (150 ml) and added to a solution of sodium acetate (7.2 g, 0.088 mole) in water (100 ml). The oil obtained was extracted into ethyl acetate, filtered to remove some insoluble material (0.4 g), dried and evaporated to dryness. The residue was crystallised from ethanol to give three crops of 2-(acetylmethylthio)benzimidazole (2), as colourless crystals, 15.0 g, 73%, mp. 112°-113° C. PMR was consistent with a tautomeric mixture of the open chain and ring closed forms.

Provenance & Evidence