Phosphorus oxychloride → 5-chloro-8-ethyl-2-methyl-8H-pyrazolo[1,5-a]pyrazolo[4',3':5,6]pyrido[3,4-e]pyrimidine

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Reaction Steps

161 g of 8-ethyl-2-methyl-4H-pyrazolo[1,5-a]pyrazolo-[4',3':5,6]pyrido[3,4-e]pyrimidin-5(8H)-one (0.06 mol) are heated with stirring in 1 liter of phosphorus oxychloride at 80° for 48 hours. The mixture is decomposed by pouring onto crushed ice. The 5-chloro-8-ethyl-2-methyl-8H-pyrazolo[1,5-a]pyrazolo[4',3':5,6]pyrido[3,4-e]pyrimidine is filtered off and recrystallized from butyl alcohol, yield 148 g (86%); m.p. 179°-180°.

Provenance & Evidence