Water → 2-[(4-Difluoromethoxy-3-methyl-2-pyridyl)methylthio]benzimidazole

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Reaction Steps

In N,N-dimethylforamide (DMF) (100 ml) was dissolved 2-[(4-hydroxy-3-methyl-2-pyridyl)methylthio]benzimidazole (10.5 g). To the solution was added 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU) (7.1 g), to which was introduced chlorodifluoromethane for 3 hours at room temperature. The reaction mixture was poured into water (500 ml), which was subjected to extraction with ethyl acetate. The ethyl acetate layer was washed with water and dried (MgSO4), then the solvent was distilled off. The residue was subjected to a silica gel column chromatography. From the portion eluted with chloroform-methanol (100:1, v/v), 2-[(4-difluoromethoxy-3-methyl-2-pyridyl)methylthio]benzimidazole was obtained (2.5 g, 20%). Recrystallization from ethyl acetate - hexane gave colorless needles, m.p. 99°-100° C.

Provenance & Evidence