Using 2-benzylthio-5-methyl-7-hydroxyl-1,2,4-triazolo[1,5-a]pyrimidine as starting compound, twenty novel 1,2,4-triazolo[1,5-a]pyrimidine derivatives containing 1,2,4-triazole-5-thione Schiff-base unit were synthesized through sequential reactions of etherification, hydrazinolysis, salification, cyclization and condensation. Target compounds were fully characterized by IR, 1 H NMR, MS techniques and elemental analysis. Preliminary bioassay indicated that some compounds exhibited certain fungicidal or good anti-TMV activities. At the concentration of 500 μg/mL, the inhibition rates of compounds 6b, 6f and 6p against tobacco mosaic virus (TMV) were 41%, 43% and 40%, respectively.

Using 3-methyl-4-amino-1,2,4-triazole-5-thione, aromatic aldehydes and 4-chloroquinazoline as starting materials, fourteen novel quinazoline derivatives containing 1,2,4-triazole Schiff-base unit were synthesized. The structures of target compounds were fully characterized by IR, 1 H NMR, MS and elemental analysis. The preliminary bioassay showed that some compounds possessed certain fungicidal activities. At the concentration of 50 μg/mL, the inhibition rates of compound 6g against F. oxysporium, C. mandshurica and P. infestans were 71%, 72% and 58%, respectively.

Twenty four novel 2-benzylsulfonyl-5-methyl-1,2,4-triazolo[1,5-a]pyrimidine-7-oxoacetohydrazone derivatives 5a～5x were synthesized by utilization of 2-benzylthio-5-methyl-7-hydroxyl-1,2,4-triazolo[1,5-a] pyrimidine as starting material. All the target compounds were characterized by 1 H NMR, IR, MS and elemental analysis. The preliminary bioassay indicated that the inhibition rates of 4-methoxybenzaldehyde N- [2-benzylsulfonyl-5-methyl-1,2,4-triazolo[1,5-a]pyrimidine]-7-oxoacetohydrazone (5k), 2-choro-5-nitrobenzaldehyde N- [2-benzylsulfonyl-5-methyl-1,2,4-triazolo[1,5-a]pyrimidine]-7-oxoacetohydrazone (5p) and cinnamaldehyde N- [2-benzylsulfonyl-5-methyl-1,2,4-triazolo[1,5-a]pyrimidine]-7-oxoacetohydrazone (5s) against Botrytis cinerea reached above 70% at the concentration of 50 μg/mL.