反应详情

90 g (214 mmol) of ethyl 5,6-dihydro-5-(2,4-dimethoxybenzyl)-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxylate are heated to reflux while stirring for 3 hours in 300 ml of trifluoroacetic acid. After evaporation in vacuo, the residue is treated with water and made alkaline with 10 percent potassium carbonate solution. The separated material is filtered off under suction, washed with water and dried in vacuo. After recrystallisation from chloroform/hexane, there is obtained ethyl 5,6-dihydro-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxylate of melting point 248°-250° C.

1. temperatureto reflux
2. customAfter evaporation in vacuo
3. additionthe residue is treated with water
4. filtrationThe separated material is filtered off under suction
5. washwashed with water
6. customdried in vacuo
7. customAfter recrystallisation from chloroform/hexane