Dimethoxypyrimidines as Novel Herbicides. Part 1. Synthesis and Herbicidal Activity of Dimethoxyphenoxypyrimidines and Analogues

Article abstract of DOI:10.1002/(SICI)1096-9063(199606)47:2<103::AID-PS396>3.0.CO;2-Z

A number of 6-(4-phenoxyphenoxy)pyrimidines and triazines were synthesized and their herbicidal activity was measured. Compounds with the methoxy groups at the 2- and 4-positions on the pyrimidine and triazine rings exhibited high herbicidal activity. Introduction of a substituent into the 5-position of the pyrimidine ring diminished the activity. In the phenoxyphenoxy substructure at the 6-position, the central ether bond can be replaced by a methylene group without loss of activity. The optimum substituent on the terminal phenyl ring was 3-trifluoromethyl. The compounds showed a strong Hill reaction inhibition, but unfortunately showed poor selectivity between weeds and crops. - Keywords: phenoxyphenoxypyrimidines; phenoxyphenoxy-s-triazines; Hill reaction inhibitors; 2,6-dimethoxy-4-<4-(3-trifluoromethylphenoxy)phenoxy>pyrimidine; 2,6-dimethoxy-4-<4-(3-trifluoromethylphenoxy)phenoxy>-s-triazine; herbicides