Phosphorus oxychloride → methyl 2-chloro-1H-1,3-benzodiazole-7-carboxylate

Participants

Reaction Conditions

Reaction Steps

A solution of methyl 2-oxo-2,3-dihydro-1H-benzimidazole-4-carboxylate (prepared as described in US2009/186879) (2.0 g) in phosphoryl chloride (18 mL) was stirred at 120° C. for 2.5 hours. Excessive phosphoryl chloride was removed under reduced pressure. To the residue was added saturated aqueous sodium bicarbonate under ice-cooling, and it was extracted with ethyl acetate. The ethyl acetate layer was dried over anhydrous magnesium sulfate and concentrated. The residue was purified on column chromatography to obtain the titled compound (1.5 g) as white powder.

Provenance & Evidence