Phosphorus oxychloride → 5,8-Dichloro-2-methylpyrazolo[1,5-a]pyrido[3,4-e]pyrimidine

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Reaction Steps

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).

Provenance & Evidence