Versatile Synthetic Approaches Towards Aza-analogues of Illudin and Ptaquilosin Sesquiterpenes

Abstract

Indolizidinones with a α-spirocyclopropane group, obtained by 1,3-dipolar cycloaddition of chiral pyrroline nitrones to bicyclopropylidene, or methylenespiropentane, and thermal rearrangement of the adducts, have been synthesized as aza-analogous skeleton to the potent carcinogenic sesquiterpenes ptaquiloside and illudin. Their moderate DNA cleaving activity on a pUC18 DNA plasmid furnishes useful hints about structure-activity relationships for this class of compounds.