In search of novel low toxicity and potent herbicides, nine title compounds were synthesized by the multi-step reaction using 2-chloro-5-(chloromethyl)pyridine or 2-chloro-5-(chloromethyl)thiazole as starting materials, followed by the cyclization with ethyl acetoacetate, hydrolysis, halogenation and the condensation with 2-amino-4,6-disubstituted-pyrimidines. The structures of the target compounds were characterized by IR, ¹H NMR, MS spectra and elemental analysis. Preliminary bioassays show that the target compounds possess good herbicidal activities against selected weeds at a concerntration of 100 mg/L.

Key words: thiazole, amide, 1,2,3-triazole, pyrimidine, herbicidal activity, substituted pyridine