反应详情

Cyanoacetylurea (38.7 g) was suspended in N,N-dimethylformamide (77.4 ml), and acetaldehyde (18.8 ml), acetic acid (3.43 ml) and ammonium acetate (2.31 g) were added. This suspension was subjected to catalytic hydrogenation in the presence of 10% palladium carbon (0.78 g, 50% wet product) under normal pressure at 30° C. for 5 hours. The catalyst was filtered off. Water (350 ml) was added to the filtrate to allow precipitation of crystals. The crystals were collected by filtration to give crystals of N-(2-cyanobutanoyl)urea (yield 24.2 g). 1H-NMR(270 MHz, DMSO-d6)δ 0.99(3H,t), 1.75-1.95(2H,m), 3.86(1H,t), 7.42(2H,br), 10.50(1H,br)

1. filtrationThe catalyst was filtered off
2. additionWater (350 ml) was added to the filtrate
3. customprecipitation of crystals
4. filtrationThe crystals were collected by filtration