Butyryl chloride → Methyl-2-n-propyl-benzimidazole-5-carboxylate

Participants

Reaction Steps

A solution of 23.9 g (100 mMol) of methyl 3,4-diaminobenzoate dihydrochloride and 11.7 g (110 mMol) of butyric acid chloride in 100 ml of phosphorus oxychloride is refluxed for 2 hours. Then about 80 ml of phosphorus oxychloride are distilled off and the residue is mixed with about 150 ml of water. The oily crude product precipitated is extracted three times with 50 ml of ethyl acetate and after evaporation purified by column chromatography (600 g of silica gel; eluant:methylene chloride/methanol (30:1)). Yield: 15.0 g of oil (69% of theory)

Provenance & Evidence