Thionyl Chloride → 4-Chloro-1-ethyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile

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Reaction Steps

10.3 g. of 1-ethyl-4-hydroxy-1H-pyrazolo-[3,4-b]pyridine-5-carboxamide (0.05 mol.) and 125ml. of thionyl chloride are refluxed for 3.5 hours. After cooling, the thionyl chloride is removed in vacuo and the residue is extracted twice with 400ml. of refluxing hexane. The combined extracts are treated with charcoal, filtered and evaporated. The product, 4-chloro-1-ethyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile, is recrystallized from a small amount of hexane, yield 2.9 g. (28%), m.p. 100°-102°.

Provenance & Evidence