反应详情

3.9 g (0.025 mol) of phenyl chloroformate and 0.05 g of 4-dimethylamino-pyridine are added in succession to a solution of 9.0 g (0.05 mol) of 2-amino-4-difluoromethoxy-6-methyl-pyrimidine in 30 ml of absolute tetrahydrofuran. The solution is stirred at 20°-25° C. for 24 hours and the reaction mixture is then diluted with 250 ml of ethyl acetate and the precipitate is separated off. 3.1 g of 2-amino-4-difluoromethoxy-6-methyl-pyrimidine hydrochloride of melting point 204°-205° C. (decomposition) are thus obtained. To remove the residual starting material, the filtrate is eluted over a column containing the ion exchanger I® (MERCK), and the eluate is dried over sodium sulfate and evaporated. 4.0 g of 2-phenoxycarbonylamino-4-difluoromethoxy-6-methyl-pyrimidine are obtained as the crude product in the form of a viscous oil. After crystallisation, the product has a melting point of 56°-58° C.

1. customthe precipitate is separated off