Limitation of cupric bromide for selective side-chain bromination of methyl aryl ketones

Abstract

2-Hydroxy-4,6-dimethoxyacetophenone and its acetate undergo nuclear bromination with cupric bromide, and 2,3,4-trimethoxyacetophenone gave w-bromo-2-hydroxy-3,4-dimethoxyacetophenone accompanied by a small yield of 2-hydroxy-3,4-dimethoxyacetophenone and by w-bromo-2,3,4-trimethoxyacetophenone. Formation of the last compound was shown by isolation of w-acetoxy-2,3,4-trimethoxyacetophenone after treatment of the mixture of brominated products with sodium acetate in ethanol.