New efficient syntheses of 6,7-dibromoquinoline-5,8-diones

Abstract

Key intermediates for potential antitumor or antifungal agents, 2- and 3-methyl-6,7-dibromoquinoline-5,8-diones have been synthesized from 2,5-dimethoxyaniline and acrolein derivatives in three-step-one-pot with 38-41% isolation yields using Skraup reaction. The three steps are ring formation of quinoline, didemethylation, and oxidation of hydroquinone including dibromination on C6 and C7 positions.