反应详情

To a solution of 9.0 g of 2-amino-4-difluoromethoxy-6-methyl-pyrimidine in 30 ml of absolute tetrahydrofuran are added successively 3.9 g of chloroformic acid-phenyl ester and 0.05 g of 4-dimethylamino-pyridine. After the solution has been stirred at 20° to 25° C. for 24 hours, the reaction mixture is diluted with 250 ml of ethyl acetate, and the occurring precipitate is separated. There are thus obtained 3.1 g of 2-amino-4-difluoromethoxy-6-methyl-pyrimidine hydrochloride, m.p. 204° to 205° C. (decomposition). In order to remove the residual starting material, the filtrate is eluted through an acid with ion-exchanger I®(MERCK), dried over sodium sulfate and concentrated by evaporation to thus obtain as crude product, in the form of a viscous oil, 4.0 g of 2-phenoxycarbonylamino-4-difluoromethoxy-6-methyl-pyrimidine (compound No. 2.28), which melts at 56° to 58° C. after crystallisation;

1. customthe occurring precipitate is separated
2. customIn order to remove the
3. washthe filtrate is eluted through an acid with ion-exchanger I®(MERCK)
4. dry with materialdried over sodium sulfate
5. concentrationconcentrated by evaporation