Synthesis
The general procedure for the synthesis of 2-bromo-4-fluoro-6-methylbenzoic acid from the compound (CAS: 1262396-02-0) was as follows: 2-bromo-4-fluoro-6-methylbenzamide (0.9 g, 3.9 mmol) was dissolved in 75% aqueous sulfuric acid (4 mL) and heated to 80 °C. Sodium nitrite (0.5 g, 7.2 mmol) was added slowly over a period of 1 h. Continuous generation of nitrogen dioxide gas was observed during the reaction. Upon completion of the reaction, the mixture was cooled to 20 °C and diluted by adding cold water (15 mL). The product was extracted several times with ethyl acetate (6 x 2 mL). The organic phases were combined, washed sequentially with water (4 × 2 mL) and brine (2 × 2 mL), dried over anhydrous sodium sulfate, filtered and concentrated to give 0.879 g of pure 2-bromo-4-fluoro-6-methylbenzoic acid in 97% yield. The product was characterized by 1H NMR (400 MHz, DMSO-d6) and 13C NMR (300 MHz, DMSO-d6 + CCl4), and the data were consistent with the expected structure.
References
[1] Patent: WO2011/6803, 2011, A1. Location in patent: Page/Page column 35
[2] Patent: WO2014/64149, 2014, A1. Location in patent: Page/Page column 27; 28
