Lawesson's reagent → 7-bromo-4,5-dihydrospiro[benzo[b][1,4]diazepine-3,1'-cyclopropane]-2(1H)-thione

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Reaction Steps

A solution of 7-bromo-4,5-dihydrospiro[benzo[b][1,4]diazepine-3,1′-cyclopropan]-2(1H)-one (267 mg, 1.0 mmol) and Lawesson's reagent (606 mg, 1.5 mmol) in tetrahydrofuran (15 mL) was heated to 80° C., and maintained at the same temperature for 1 hours. The mixture was concentrated. To the residue was added water (50 mL), extracted with ethyl acetate (50 mL). The organic phase was washed with water (50 mL*2), dried by sodium sulfate, filtered and concentrated to give a residue. The residue was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=6:1) to afford 7-bromo-4,5-dihydrospiro[benzo[b][1,4]diazepine-3,1′-cyclopropane]-2(1H)-thione (125 mg, 44%).

Provenance & Evidence