Synthetic Disproof of the Structure Proposed for Alectrol, the Germination Stimulant fromVigna unguiculata

Abstract

Several compounds [(±)-3a, (±)-3b, (±)-10, (±)-11, and (±)-12] with structures related to that proposed for alectrol (3), the germination stimulant for seeds of parasitic weeds, have been synthesized. Structure (±)-3a has been solved by X-ray-crystallographic analysis. Comparison of the 1H-NMR data of the synthetic compounds with those reported for alectrol showed the proposed structure 3 to be incorrect. The synthetic products (±)-3a and (±)-3b showed significant germination stimulating activity on clover broomrape (Orobanche minor) seeds.