Synthesis
General procedure for the synthesis of 2-bromo-4-pyridinecarboxylic acid from 2-bromo-4-methylpyridine: To a stirred solution of 29.0 g (69 mmol) of 2-bromo-4-methylpyridine dissolved in 150 mL of concentrated sulfuric acid was added batchwise 67.9 g (231 mmol) of potassium dichromate. The reaction was cooled using an ice bath to maintain a constant temperature. After addition, the reaction mixture was continued to be stirred at room temperature for 2 hours. Subsequently, the reaction mixture was slowly poured into 2 L of ice water and stirred at room temperature for 1 hour. The resulting crystals were collected by filtration, washed with water until the eluent was colorless, and finally dried under vacuum to give 30.0 g (88% yield) of 2-bromo-4-pyridinecarboxylic acid.
References
[1] Patent: US2011/111046, 2011, A1. Location in patent: Page/Page column 17; 18
[2] Patent: WO2011/58473, 2011, A1. Location in patent: Page/Page column 36; 37
[3] Chemical and Pharmaceutical Bulletin, 1990, vol. 38, # 9, p. 2446 - 2458
[4] Patent: US2008/51397, 2008, A1. Location in patent: Page/Page column 9; 24
[5] Polyhedron, 2016, vol. 118, p. 159 - 170
