Synthesis and lateral root-inducing activity of novel 2-piperidones with a 1,4-benzodioxan ring

A series of novel N-benzyl-2-piperidones having a 1,4-benzodioxan ring was synthesized and investigated for their activity to induce lateral roots in the lettuce seedlings. N-Benzyl-3-[1-(3,6-benzodioxanyl)-1-hydroxymethyl]-2-piperidone (23) induced 100% emergence of lateral roots at 100 ppm. There was no significant difference in activity between the erythro-arid threo-23. The introduction of a benzyloxymethyl substituent at the 2-position on the 1,4-benzodioxan ring slightly increased the activity compared with that of 23, showing some activity even at 1 ppm, while the activity was found to fall off sharply with a methoxy group adjacent to the 1,4-dioxane ring.