Abstract
When mixtures of 7-chloro-3-phenyl-3H-1, 2, 3-triazolo [4, 5-d] pyrimidine (4), aromatic aldehydes (5), and a catalytic amount of 1, 3-dimethylbenzimidazolium iodide were refluxed in tetrahydrofuran (THF) in the presence of sodium hydride, 7-aroyl-3-phenyl-3H-1, 2, 3-triazolo [4, 5-d]-pyrimidines (1) were obtained in moderate yields. Although the yield was unsatisfactory, the reaction of 1 with sodium hydroxide in dimethyl sulfoxide (DMSO) resulted in aryl migration, followed by ready oxidative decarboxylation, giving 7-aryl-3-phenyl-3H-1, 2, 3-triazolo [4, 5-d]-pyrimidines (3) by way of 7-aryl-6, 7-dihydro-3-phenyl-3H-1, 2, 3-triazolo [4, 5-d] pyrimidine-7-carboxylic acids (2). When the reaction mixture of 1 with sodium hydroxide was directly subjected to potassium ferricyanide oxidation, 1 was easily convertible to 3 in good yield.
