Facile synthesis of anhydrojudaicin and 11,13-dehydroanhydrojudaicin, two eudesmanolide-skeleton lactones with potential allelopathic activity

Article abstract of DOI:10.1016/j.phytol.2019.04.014

Natural product anhydrojudaicin (7) is a eudesmanolide that has been synthesized from costunolide (1) in three steps with good yield, simplifying procedures available in the literature. The key step was the efficient oxidation and rearrangement using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). Following the same methodology, 11,13-dehydroanhydrojudaicin (8) was prepared for the first time. All compounds were characterized and tested in three specific bioassays: phytotoxicity bioassays on wheat coleoptile and on weed seeds (Amaranthus viridis, Echinochloa crus-galli and Panicum maximum); as well as bioassay of germination of parasitic weed seeds of broomrape (Orobanchaceae). The final products showed better activity profiles than the starting eudesmanolide in all bioassays. The data allow us to propose compounds 7 and 8 as leads for new natural product-based agrochemicals.