Ammonia → (S)-8-chloro-11,12,13,13a-tetrahydro-1-vinyl-9H-imidazo[1,5-a]pyrrolo[2,1-c][1,4]benzodiazepin-9-one

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Reaction Steps

20.8 g of an equimolar mixture of methyltriphenylphosphonium bromide and sodium amide were stirred for 20 minutes in 80 ml of tetrahydrofuran. 15.08 g (50 mmol) of (S)-8-chloro-11,12,13,13a-tetrahydro-9-oxo-9H-imidazo[1,5-a]pyrrolo[2,1-c][1,4]benzodiazepine-1-carboxaldehyde was then added portionwise thereto, whereby the temperature rose to 43° with the evolution of ammonia. The mixture was stirred at room temperature for 1 hour, filtered and the filtrate was evaporated. After chromatography of the residue on silica gel while eluting with cyclohexane/ether/isopropanol (3:3:1) and recrystallization from ethyl acetate there was obtained (S)-8-chloro-11,12,13,13a-tetrahydro-1-vinyl-9H-imidazo[1,5-a]pyrrolo[2,1-c][1,4]benzodiazepin-9-one of melting point 213°-215°.

Provenance & Evidence