Synthesis of Dimethoxyfuranonaftoquinones

Abstract

Recently some furanonaphthoquinones were isolated from Tabebuia species^2,3,4. The structures la, lb2, and li4 were assigned to three of these compounds (those of la and lb being later confirmed by synthesis^3,5,6). However, for the three other isolated compounds the spectroscopic data did not permit a decision to be made between the 2,3,4 - - - 4 isomeric pairs of structure lc and Id, le and lf ³, and lg and lh ⁴. Compounds la, lb, and le (or If), were tested in the KB cell culture assay and shown to be more active cytotoxic agents than lapachol^2,3, the probable biogenetic precursor of all of them.