Chloroform → 3-Chloro-6-(o-fluorophenyl)-1,2,4-triazine

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Reaction Steps

A suspension of 42.4 g. of 6-(o-fluorophenyl)-1,2,4-triazin-3(2H)-one in 350 ml. of chloroform is refluxed overnight, cooled in an ice bath, and 350 ml. of phosphorus oxychloride followed by 2.6 g. of N,N-dimethylformamide are added. The mixture is refluxed for 4.5 hours, cooled and concentrated to a brown oil. This oil is dissolved in methylene chloride, poured onto ice and made basic, giving a brown solid. The mixture is filtered and the filtrate is passed through a silica gel column giving a crystalline solid. This solid is heated with hexane and filtered giving crystals. Recrystallization from hexane gives a tan solid which sublimes on heating giving 3-chloro-6-(o-fluorophenyl)-1,2,4-triazine as tan crystals.

Provenance & Evidence