Carbon Dioxide → 7-Bromo-4-methyl-3,4-dihydro-1H-benzo[E][1,4]diazepine-2,5-dione

Participants

Reaction Steps

A solution of 39.5 g of 5-bromoisatoic acid anhydride and 14.5 g of sarcosine in 150 ml of dimethyl sulphoxide is heated to 100° C. while stirring. In so doing, a vigorous evolution of carbon dioxide occurs from 70° C. and this has finished after ca 30 minutes. The mixture is stirred at 100° C. for a further 30 minutes and thereafter the mixture is poured into 900 ml of ice-water (temperature 5° C.) and the separated material is filtered off under suction. The crystals are washed with water and subsequently dried at 50° C. over phosphorus pentoxide in a vacuum drying cabinet. There is obtained 7-bromo-3,4-dihydro-4-methyl-2H-1,4-benzodiazepine-2,5(1H)-dione in the form of light beige crystals. A sample recrystallised from methanol has a melting point of 260°-261° C.

Provenance & Evidence