Phosphorus oxychloride → HCID 85916602, compound

Participants

Reaction Steps

256 g of 8-ethyl-5,8-dihydro-5-oxo-4H-pyrazolo[1,5-a]pyrazolo[4',3':5,6]pyrido[3,4-e]pyrimidine-3-carboxylic acid, ethyl ester are refluxed in 1 liter of phosphorus oxychloride for 24 hours. The excess phosphorus oxychloride is decomposed by pouring the solution on ice and the crystallized 5-chloro-8-ethyl-8H-pyrazolo[1,5-a]pyrazolo[4',3':5,6]pyrido[3,4-e]-pyrimidine-3-carboxylic acid, ethyl ester is filtered off, yield 245 g (91%); m.p. 170°-172° (butyl alcohol).

Provenance & Evidence