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 the result of biological testing, the (S)-(-)-isomer exhibited stronger activity than the (R)-(+)-isomer. This result is contrary to those from commercial herbicides with similar structures, phenoxy- and oxyphenoxy-propionate-type compounds, where the (R)-isomers are generally known to be the active principles.