4-bromo-2,6-dimethylbenzoic acid

124-38-9

206559-43-5

74346-19-3

Example 2: Preparation of 4-bromo-2,6-dimethylbenzoic acid (B2) The title compound can be prepared according to Scheme B as follows. 5-Bromo-2-iodo-1,3-dimethylbenzene (B1) (1.0 mole equivalent) was dissolved in methyl tert-butyl ether (6.0 relative volume), and this solution was slowly added to a solution of isopropylmagnesium chloride (2.0 mole equivalents) in methyl tert-butyl ether (2.0 relative volume) that had been pre-cooled to < 0 °C. Carbon dioxide gas was passed through until the reaction was complete while maintaining low temperature conditions. Upon completion of the reaction, 2N aqueous hydrochloric acid (4 relative volume) was added to quench the reaction, the organic and aqueous phases were separated and the aqueous phase was discarded. The organic phase was extracted with 1M aqueous sodium hydroxide solution (6.5 relative volume) and subsequently washed with methyl tert-butyl ether (4 relative volume). The aqueous phase was acidified by addition of 2N aqueous hydrochloric acid (4.5 relative volume) to precipitate the title compound (B2). The precipitate was collected by filtration, washed sequentially with water and heptane and dried to give a white crystalline solid in 85% yield. 1H NMR (400 MHz, CDCl3) δH 2.28 (6H, s), 7.35 (2H, s), 13.30 (1H, s).