Hydrochloric Acid → (S)-8-chloro-7-fluoro-12,12a-dihydro-9-oxo-9H,11H-azeto[2,1-c]-imidazo[1,5-a][1,4]benzodiazepine-1-carboxylic acid

Participants

Reaction Steps

57.3 g (164 mmol) of ethyl (S)-8-chloro-7-fluoro-12,12a-dihydro-9-oxo-9H,11H-azeto[2,1-c]imidazo[1,5-a][1,4]-benzodiazepine-1-carboxylate, 40 ml of ethanol, 60 ml of water and 51.5 ml (206 mmol) of 4N sodium hydroxide solution were heated to reflux on a steam bath for 30 min. The alcohol was evaporated on a rotary evaporator. The aqueous phase remaining behind was washed twice with methylene chloride and acidified to pH 3-4 with 51.5 ml (206 mmol) of 4N hydrochloric acid. The suspension obtained was cooled and filtered, and the filter residue was washed with a small amount of ice-water and dried. There were obtained 47.92 g (91%) of (S)-8-chloro-7-fluoro-12,12a-dihydro-9-oxo-9H,11H-azeto[2,1-c]imidazo[1,5-a][1,4]benzodiazepine-1-carboxylic acid of m.p. 225°-226°.

Provenance & Evidence