反应详情

10 g of sodium are dissolved in 200 ml of absolute methanol, whereupon the solution is treated with 30 g of guanidine hydrochloride. While stirring there is added thereto a solution of 50 g of methyl[(1-ethoxy-2-ethoxycarbonyl)ethylidene]carbamate in 150 ml of absolute methanol. The resulting suspension is stirred overnight and thereafter concentrated at 40° in a water-jet vacuum. 600 ml of water are added to the residue and the resulting suspension is adjusted to pH 5 with glacial acetic acid while stirring. The resulting precipitate is filtered off under suction, washed with 250 ml of water and dried at 50° in vacuo. There is obtained methyl 2-amino-1,6-dihydro-6-oxo-4-pyrimidinecarbamate which is uniform according to thin-layer chromatography.

1. additionis added
2. stirringThe resulting suspension is stirred overnight
3. concentrationconcentrated at 40° in a water-jet vacuum
4. addition600 ml of water are added to the residue
5. stirringwhile stirring
6. filtrationThe resulting precipitate is filtered off under suction
7. washwashed with 250 ml of water
8. customdried at 50° in vacuo