Chloroform → 3-Chloro-7-(alpha,alpha,alpha-trifluoro-m-tolyl)pyrazolo[1,5-a]pyrimidine

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Reaction Steps

A 3.3 g. portion of N-chlorobenzotriazole is added to a solution of 5.26 g. of 7-(α,α,α-trifluoro-m-tolyl)pyrazolo[1,5-a]pyrimidine in 50 ml. of chloroform producing an exothermic reaction. The mixture is refluxed on a steam bath for 15 minutes, cooled to room temperature and then poured into an ice-cold solution of 2.5 N sodium hydroxide. The organic layer is separated, dried over socium sulfate and passed through a hydrous magnesium silicate column. The effluent is heated to reflux and hexane is added giving a solid. The solid is dissolved in methylene chloride re-processed through the column and precipitated from refluxing solution with hexane giving crystals of the desired product, m.p. 155°-157° C.

Provenance & Evidence