Alkylation of acyl and sulfonyl derivatives of 3,5-diamino-1-phenyl-1,2,4-triazole

Alkylation of 3-acylamino-, 5-amino-1-phenyl-3-tosylamino-1,2,4-triazoles and 3,5-diacetylamino-1-phenyl-1,2,4-triazole in the presence of an equimolar amount of sodium methylate in DMSO occurs regioselectively at the amide (sulfamide) group nitrogen atom. The benzylation of 3-acetylamino-5-amino-1-phenyl-1,2,4-triazole with excess base and benzyl chloride also alkylates the amino group at position 5. Alkylamino-1-R-1,2,4-triazoles can be conveniently prepared by alkylation of the corresponding acetylamino-1,2,4-triazoles in the presence of base and subsequent acid hydrolysis of the N-acetyl-N-alkyl derivatives.