Selective Oxidation of 2-Bromo-m-xylene to 2-Bromo-3-methylbenzoic Acid or 2-Bromoisophthalic Acid

Abstract
Aqueous sodium dichromate oxidation of 2-bromo-m-xylene (1) under a carbon dioxide pressure gave 2-bromoisophthalic acid (58%), while NBS-bromination of 1 followed by Sommelet oxidation to aldehyde and then potassium permanganate oxidation enabled the isolation of 2-bromo-3-methylbenzoic acid in 42% yield.