Synthesis and biological activity of substituted pyrimidine derivatives

Fourteen new substituted pyrimidines were synthesized and their structures were confirmed by H-1 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. The compound 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 at the 5-position on the pyrimidine ring diminished the fungicidal activity. The best substituent on phenyl ring was 2-nitro-4-trifluoromethyl.