2-Butynoic acid → 1-[1-(2,6-difluorophenyl)ethyl]-1H-1,2,3-triazole-4-carboxylic acid

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Reaction Steps

6.5 g (35 millimoles) of 1-(2,6-difluorophenyl)ethyl azide and 2.45 g (35 millimoles) of propinecarboxylic acid in 50 ml of toluene are heated for 24 hours to 60°-70° C. The cooled reaction mixture is extracted with 100 ml of 1N sodium hydroxide solution and the extract is acidified with hydrochloric acid to give 1-[1-(2,6-difluorophenyl)ethyl-1H-1,2,3-triazole-4-carboxylic acid with a melting point of 135°-138° C. (dec.). 7.1 g (26.6 millimoles) of 1-[1-(2,6-difluorophenyl)ethyl]-1H-1,2,3-triazole-4-carboxylic acid, 150 ml of ethanol and 1 ml of sulfuric acid are heated for 10 hours to reflux. Working up gives ethyl 1-[1-(2,6-difluorophenyl)ethyl]-1H-1,2,3-triazole-4-carboxylate with a melting point of 118°-121° C.

Provenance & Evidence