Effect of optically active ethyl 2-phthalimidooxypropionate on the growth of cress, Lepidium sativum

The effects of 2-phthalimidooxyalkanoic acid derivatives on the germination and root-growth of cress were examined. Since 2-phthalimidooxypropionates were most effective, the optically active ethyl esters were prepared. As th e result of biological testing, the (S)-(-)-isomer exhibited stronger activ ity than the (R)-(+)-isomer. This result is contrary to those from commerci al herbicides with similar structures, phenoxy- and oxyphenoxy-propionate-t ype compounds, where the (R)-isomers are generally known to be the active p rinciples.