In search of novel low toxicity and potent pesticide lead compounds, eight title compounds were synthesized via the condensation reactions of 1-[(heteroaryl)methyl]-5-methyl-1H-1,2,3-triazole-4-carbonyl chlorides with 5-alkyl-2-amino-1,3,4-thiadiazoles, and structurally characterized by IR, 1H NMR spectra, and elemental analysis or further by MS technique. Preliminary bioassays showed that a fraction of the target compounds possessed moderate herbicidal activities against dicotyledonous plants (Brassica campestris L) at the concerntration of 100 mg/L and insecticidal activity to some extent at the concerntration of 250 mg/L.

Key words: 1,3,4-thiadiazole, thiazole, biological activity, 1,2,3-triazole, substituted pyridine