Synthesis and Biological Activity of O-Methyl Methyl 1-(Substituted Phenoxyacetoxy)-1-(thien-2-yl)methylphosphinates

A series of novel O-methyl methyl 1-(substituted phenoxyacetoxy)-1-(thien-2-yl)methylphosphinates 5a-h were synthesized. Their structures were confirmed by IR, H-1 NMR, mass spectroscopy, and elemental analyses. The results of preliminary bioassays show that some of the title compounds exhibit moderate to good herbicidal and fungicidal activities. For example, the title compounds 5c, 5d, and 5g possess 90-100% inhibition against the tested plants at the concentration of 10 mg/L and 100 mg/L, whereas the title compounds 5a, 5b, 5c, and 5h possess 70-94% inhibition against Phyricularia grisea and Sclerotinia sclerotiorum at the concentration of 50 mg/L.