Fourteen new substituted pyrimidineswere synthesized and their structures were confirmed by ¹H NMR, IR, MS spectra and elemental analyses. Their insecticidal, fungicidal and herbicidal activities were examined. Some of these compounds showed good fungicidal activity after introduction of dimethylamino into the 2-position of pyrimidine ring. Thecompound with the phenoxy substructure at the 4-position of pyrimidine ring also showed good fungicidal activity, e.g. 3b, 3c and 3e. But compounds with methyl atthe 5-position on the pyrimidine ring diminished the fungicidal activity. Thebest substituent on phenyl ring was 2-nitro-4-trifluoromethyl.

Key words: pyrimidine, synthesis, biological activity, fungicidal activity