1-(2,4-difluorophenyl)pyrrolidin-2-one

Conditions: temp:100.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 64.6 g of 2,4-difluoroaniline, 51.7 g of butyrolactone, 2 g of p-toluenesulphonic acid and a few drops of water is warmed to reflux (100 ° C.) with stirring. The water which forms is removed by distillation via a vigorous stream of nitrogen. During this operation, the internal temperature increases to 162° over the course of 15 hours. After cooling to room temperature, the mixture is diluted with 100 ml of diethyl ether. The ether solution is washed first with 5% strength HCl and then with 10% strength NaOH, dried and evaporated. The crystalline residue is recrystallized from ethanol. The 1-(2,4-difluorophenyl)pyrrolid-2-one obtained melts at 95°-97°. is warmed The water which forms is removed by distillation via a vigorous stream of nitrogen During this operation, the internal temperature increases to 162° over the course of 15 hours After cooling to room temperature the mixture is diluted with 100 ml of diethyl ether The ether solution is washed first with 5% strength HCl with 10% strength NaOH, dried evaporated The crystalline residue is recrystallized from ethanol