反应详情

4.1 g of ethyl α-amino-1,3,4,5-tetrahydro-5-oxo-2H-1,4-benzodiazepin-2-ylidene-acetate are dissolved in 25 ml of ethyl acetate, treated with 3.1 ml (18.1 mmol) of N,N-dimethylformamide diethyl acetal and heated to boiling under reflux for 0.5 hour. After cooling, the separated material is filtered off under suction and recrystallised from ethanol. After chromatography of the mother liquor, there is obtained a second portion of ethyl 5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxylate of the same purity; melting point 166°-168° C.

1. temperatureheated
2. temperatureunder reflux for 0.5 hour
3. temperatureAfter cooling
4. filtrationthe separated material is filtered off under suction
5. customrecrystallised from ethanol