反应详情

73.5 g (290 mmol) of 2-[4-(p-chlorophenyl)-2-oxopyrrolidin-1-yl]-acetic acid are suspended in 900 ml of tetrahydrofuran; 92.5 g (350 mmol) of pentachlorophenol are added and the whole is stirred at room temperature until a clear solution is obtained. The solution is cooled in an ice bath, 65.8 g (319 mmol) of dicyclohexylcarbodiimide dissolved in 180 ml of tetrahydrofuran are added dropwise thereto within a period of 30 minutes and the whole is stirred for a further 1 hour in the ice bath and for a further 16 hours at room temperature; the resulting dicyclohexylurea is filtered off and the filtrate is concentrated to dryness by evaporation under reduced pressure at 60° and recrystallised from 400 ml of ethyl acetate. 2-[4-(p-chlorophenyl)-2-oxopyrrolidin-1-yl]-acetic acid pentachlorophenyl ester having a melting point of 135°-136° is obtained. Additional product can be obtained by concentrating the mother liquor.

1. customis obtained
2. temperatureThe solution is cooled in an ice bath
3. additionare added dropwise
4. filtrationthe resulting dicyclohexylurea is filtered off
5. concentrationthe filtrate is concentrated to dryness by evaporation under reduced pressure at 60°
6. customrecrystallised from 400 ml of ethyl acetate