反应详情

150 g of methyl 2-amino-6-[(p-tolylsulfonyl)oxy]-4-pyrimidinecarbamate-3-oxide are suspended in 2 l of methylene chloride and 2 l of water while stirring. After cooling to 0°-5°, 50 ml of methyl chloroformate are added thereto. After stirring vigorously for about 10 minutes, the mixture is adjusted to a pH of 7-7.5 with about 150 g of sodium bicarbonate. The mixture is subsequently stirred at 0°-5° for a further 3 hours. The organic phase is separated and the aqueous phase is extracted with 1 l of methylene chloride. The combined organic phases are washed twice with 1 l of water each time, dried over sodium sulphate and evaporated in vacuo. There is obtained crude dimethyl 6-[(p-tolylsulfonyl)oxy]-2,4-pyrimidinedicarbamate-3-oxide which is used in the next step (a pure product of melting point 178°-180° can be obtained by digestion with ethyl acetate).

1. temperatureAfter cooling to 0°-5°
2. stirringThe mixture is subsequently stirred at 0°-5° for a further 3 hours
3. customThe organic phase is separated
4. extractionthe aqueous phase is extracted with 1 l of methylene chloride
5. washThe combined organic phases are washed twice with 1 l of water each time
6. dry with materialdried over sodium sulphate
7. customevaporated in vacuo