ethyl 5-(2,4-dimethoxybenzyl)-8-fluoro-5,6-dihydro-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxylate → N-Desmethylflumazenil

Participants

Reaction Steps

13.0 g (29.6 mmol) of ethyl 5-(2,4-dimethoxybenzyl)-8-fluoro-5,6-dihydro-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxylate are heated to boiling under reflux for 4 hours in 45 ml of trifluoroacetic acid. After evaporation of the dark red suspension in vacuo, the residue is treated with water and made alkaline with ca 100 ml of 15 percent potassium carbonate solution. The separated material is filtered off under suction and washed with water. After recrystallisation from ca 500 ml of ethanol, there is obtained ethyl 8-fluoro-5,6-dihydro-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxylate of melting point 298° C.

Provenance & Evidence