Synthesis of 4-amino-5-(4,6-diphenyl-2-pyrimidinyl)-3,4-dihydro-2H-1,2,4-triazo l e-3-thione and its reactions with C-electrophiles

4-Amino-5-(4,6-diphenyl-2-pyrimidinyl)-3,4-dihydro-2H-1,2,4-trazol e-3- thione is formed from the reaction of 4,6-diphenylpyrimidinecarboxylic acid or its ethyl ester with thiocarbonyl hydrazide. Alkylation of the product leads to S-alkyl derivaties or 6-substituted 3-(4,6-diphenyl-2-pyriimidinyl)-7H-1,2,4-triazolo[3,4-b]-1,3,4-thi a diazine. Acetylation of 4-amino-5-(4,6-diphenyl-2-pyrimidinyl)-3,4-dihydro-2H-1,2,4-triazo l e-3-thione gave under different conditions monoacetyl-, diacetyl, and triacetyl derivatives at the amino group and the N sub((2)) atom, whereas benzoylation gave a benzoyl group at the amino group and 3-(4,6-diphenyl-2-pyrimidinyl)-6-phenyl-1,2,4-triazolo[3,4-b]-1,3, 4 -thiadiazole.