Synthesis of New Azocompounds and Fused Pyrazolo[5,1‐c][1,2,4]triazines Using Heterocyclic Components

Diazotization of 3-methyl-4-phenyl-1H-pyrazol-5-amine 1 in hydrochloric acid has been reported to afford the corresponding diazonium salt 2. The latter underwent azocoupling with a variety of active methylene compounds (barbituric 3a and thiobarbituric 3b acid, 2-hetarylpyrimidine-4,6-dione 6a, 6b, 4-hydroxy-6-methylpyridin-2(1H)-one 10a, 4-hydroxy-6-methyl-2H-pyran-2-one 10b, 4-hydroxy-1-p-tolyl-1H-pyrazole-3-carboxylic acid ethyl ester 14, 1,3-thiazolidine-2,4-dione 16a, 2-thioxo-1,3-thiazolidin-4-one 16b) to yield new pyrazolylazo derivatives. Fused pyrazolo[5,1-c][1,2,4]triazines 5, 9a, 9b, 12, 13 were obtained by heterocyclization reactions. Copyright © 2013 HeteroCorporation