Phosphorus oxychloride → HCID 178469780, compound

Participants

Reaction Steps

22.1 g. of 4-hydroxy-3-methyl-1H-pyrazolo[4,3-c]pyridine-7-carboxylic acid ethyl ester (0.1 mol.) and 100 ml. of phosphorus oxychloride are refluxed for 10 hours. After this time, the excess phosphorus oxychloride is removed by distillation. The oily residue is poured into 50 ml. of ice water. On neutralization with aqueous ammonia, 4-chloro-3-methyl-1H-pyrazolo[4,3-c]-pyridine-7-carboxylic acid ethyl ester crystallizes and is filtered. Recrystallization yields 12 g. (50%), m.p. 180°.

Provenance & Evidence