Synthesis of the naturally occurring indolequinone BE 10988, an inhibitor of topoisomerase II
Abstract
A short synthesis (28% overall yield) of the naturally occurring indolequinone BE 10988 1 is described. The synthesis starts from 4-benzyloxy-5-methoxyindole and involves, as key steps, the use of chlorosulfonyl isocyanate to introduce the amide side-chain into the indole 3-position, followed by thioamide formation and construction of the thiazole ring using a Hantzsch reaction.