Synthesis and herbicidal activities of O-methyl methyl[1-(substituted phenoxyacetoxy)alkyl]phosphinates

A series of new methyl methyl[1-(substituted phenoxyacetoxy)alkyl]phosphinates was designed and synthesized. Their structures were confirmed by IR, 1H NMR, 31P NMR, MS and elemental analysis. The results of bioassay showed that some of the target compounds exhibited excellent herbicidal activities to Triticum aestivum L, Digitaria sanguinalis Scop, Echinochloa crusgalli Beava, Brassica napus L., and Cirsium japonicum DC in pre- and post-emergence treatment at a dosage of 150 g ai/ha. It could be found that the structure of substituent X or Y on a benzene ring had a very important effect on herbicidal activity; compounds 7a, 7b, 7c, and 7i have especially enhanced herbicidal activity and higher selectivity between monocotyledon crops and weeds.