反应详情

A mixture of 30.0 g of 9,10-dimethoxy-3,4,6,7-tetrahydro-2H-pyrimido(6,1-a)isoquinolin-2,4-dione and 300 ml of phosphorus oxychloride is heated on a steam bath for 4 hours. The excess of phosphorus oxychloride is distilled under reduced pressure. The residue is poured into a cold solution of sodium hydroxide. A yellow solid precipitates which is collected by filtration. The product is purified by passage through a silica gel column using chloroform as eluent. Yield 28.0 g, m.p. 235°-236° C.

1. temperatureis heated on a steam bath for 4 hours
2. distillationThe excess of phosphorus oxychloride is distilled under reduced pressure
3. additionThe residue is poured into a cold solution of sodium hydroxide
4. customA yellow solid precipitates which
5. filtrationis collected by filtration
6. customThe product is purified by passage through a silica gel column