反应详情

23.5 g. of 8-chloro-2-methylpyrazolo[1,5-a]pyrido[3,4-e]pyrimidin-5(4H)-one of Example 1b are refluxed in 100 ml. of phosphorus oxychloride for 12 hours. The excess phosphorus oxychloride is distilled off in vacuo and the oily residue is poured on ice. After standing for 1 hour, 5,8-dichloro2-methylpyrazolo[1,5-a]pyrido[3,4-e]pyrimidine is filtered off, yield: 17 g. (67%); m.p. 203.4° (ethyl acetate).

1. distillationThe excess phosphorus oxychloride is distilled off in vacuo
2. additionthe oily residue is poured on ice
3. filtration5,8-dichloro2-methylpyrazolo[1,5-a]pyrido[3,4-e]pyrimidine is filtered off