反应详情

48.8 g of 4-bromo-3-chlorobenzylhydrazine are added dropwise under nitrogen to a solution of 33.2 g of β-amino-β-ethoxyacrylic acid ethyl ester and 1.5 g of toluenesulphonic acid in 150 ml of ethanol. After stirring for a further two hours, the mixture was left to stand and the compound identified above began to crystallise out after four hours. It was filtered off and twice recrystallised from ethanol. Melting point: 145°-146°, 23 g (37%).

1. waitthe mixture was left
2. customto crystallise out after four hours
3. filtrationIt was filtered off
4. customtwice recrystallised from ethanol