Synthesis of phenylacetylene containing 1,2,3-triazole group

Bromination of (E)-1-[4-(2-carboxy-vinyl)phenyl]-[1,2,3]triazole-4-carboxylic acid ethyl ester, which was synthesized in 90% yield by a Huisgen-type [3 + 2]-cycloaddition reaction between 3-(4-azidophenyl) acrylic acid and ethyl propiolate, in CHCl₃ followed by a debrominative decarboxylation reaction with Et₃N in DMF under microwave irradiation condition afforded stereoselective (Z)-1-(4-(2-bromovinyl)phenyl)-1,2,3-triazole-4-carboxylic acid ethyl ester in 94% yield. Treatment of (Z)-1-(4-(2-bromovinyl)phenyl)-1,2,3-triazole-4-carboxylic acid ethyl ester with EtONa in DMF afforded 1-(4-ethynylphenyl)-1,2,3-triazole-4-carboxylic acid ethyl ester in a yield of 90%.