Synthesis of 3-Methoxyellipticine and Ellipticine by Friedel-Crafts Reaction of Indole-2,3-dicarboxylic Anhydride and Selective Demethylation

摘要: Reaction of 1-benzylindole-2,3-dicarboxylic anhydride with 2,4,6-trimethoxypyridine in the presence a Lewis acid gave 1-benzyl-3-(2,4,6-trimethoxynicotinoyl)indole-2-carboxylic as sole product high yield, which could be changed to 1-benzyl-3-(2,4,6-trimethoxynicotinoyl)indole. 1-Benzyl-3-(2,4,6-trimethoxynicotinoyl)indole was converted 3-methoxy-ellipticine and ellipticine by selective demethylation triflation methoxy group.