Synthesis of ellipticine by reaction of 1-(4-methoxybenzyl)indole-2,3-dicarboxylic anhydride with (3-bromo-4-pyridyl)triisopropoxytitanium

Abstract

Reaction of 1-benzyl- and 1-(4-methoxybenzyl)indole-2,3-dicarboxylic anhydride with (3-bromo-4-pyridyl)triisopropoxytitanium gave the corresponding 2-acylindole-3-carboxylic acids as the sole product. Deprotection of the 1-(4-methoxybenzyl) group of the 2-acylindole-3-carboxylic acid was performed by treatment with perchloric acid in acetic acid to afford 2-(3-bromoisonicotinoyl)indole, which was converted to ellipticine.