Hydrochloric Acid → 5,6-Dichloro-2-(1,2,2,2-tetrafluoroethyl)-1H-benzimidazole

Participants

Reaction Conditions

Reaction Steps

4,5-Dichloro-benzene-1,2-diamine (2.03 g; 11.5 mmoles) and 2,3,3,3-tetrafluoro-propionic acid (1.99 g; 13.6 mmoles) were suspended in 6N HCl (5 mL; 30 mmoles) under a nitrogen atmosphere. The reaction was stirred vigorously and heated to 108° C. for 18 hrs, then cooled to room temperature. The reaction was diluted with water (60 mL) and with ethyl acetate (60 mL), then sodium bicarbonate (4.02 g; 47.9 mmoles) was added slowly and in portions to quench the reaction. The aqueous layer was separated and extracted with ethyl acetate (3×30 mL). The extracts were combined, washed with water (30 mL) and brine (30 mL), then dried over Na2SO4. The filtrate was concentrated in vacuo to yield a crude brown solid. A sample of the crude brown solid was purified by column chromatography (SiO2; 100% CH2Cl2) to yield the title compound as a light orange solid.

Provenance & Evidence