The regioselective addition reaction of 5-amino-1,2,4-triazoles and its pyrazole analogues 1 with arylsulfonyl isocyanates were described. Experimental results showed that the addition reaction of 1 with arylsulfonyl isocyanates at room temperature took placed at the 5-position amino group and adducts 4 were obtained, however, the reaction proceeded at 1-N at the presence of sodium hydride to give products 5, which suggested that the amino nitrogen at C-5 is more nuclophilic than 1-N in this reaction system. In addition, molecul...
