反应详情

温度

85 °C

A mixture of 30.6 g of glyoxylic acid butyl ester butyl hemiacetal (0.15 mol), 30.0 g of urea (0.5 mol), 300 g of n-butanol and 7.5 g of 8% strength butanolic sulfuric acid was heated at 85° C. for a total of 4 hours. After the reaction had ended, the suspension formed was cooled to room temperature, whereupon a colorless precipitate separated out, which was filtered off, washed with methanol and dried in vacuo at 75° C. 23.1 g, that is to say 66% of theory, of crystalline allantoin acid butyl ester were obtained by this reaction.

1. customthe suspension formed
2. temperaturewas cooled to room temperature, whereupon a colorless precipitate
3. customseparated out
4. filtrationwhich was filtered off
5. washwashed with methanol
6. customdried in vacuo at 75° C