Synthesis and Lateral Root-Inducing Activity of NovelN-Substituted-2-Piperidones with a 1,4-Benzodioxan Ring

Novel N-substituted-2-piperidones with a 1,4-benzodioxan ring were prepared and evaluated for their activity to induce lateral roots in lettuce seedlings. Compounds were obtained by aldol condensation of the lithium enolate of N-substituted-2-piperidones with 1,4-benzodioxan-6-carbaldehyde. Of the series compounds tested, N-cinnamyl-3-[1-(1,4-benzodioxan-6-yl)-1-hydroxymethyl]-2-piperidone (2e) had the highest activity. In seedlings treated with 10 ppm of 2e, all of the primary roots formed lateral roots. Only erythro-2e showed lateral root-inducing activity, while threo-2e was inactive.