Synthesis
General procedure for the synthesis of 6-bromo-2-chloro-4-methylquinoline from 6-bromo-4-methyl-2(1H)-quinolinone: 25 mL of phosphorochloridic acid was added to 2.7 g (11.34 mmol) of 6-bromo-4-methyl-1H-quinolin-2-one (Example 1b), and the reaction mixture was refluxed for 2 hours. Upon completion of the reaction, it was cooled to room temperature and the mixture was slowly poured into 250 mL of 10% ammonia solution to precipitate. The precipitate was collected by filtration, washed with water and dried in a circulating air dryer at 30 °C. A product of 2.7 g was obtained in 93% yield. Product characterization: C10H7BrClN (M = 256.526); calculated molecular ion peak (M + H)+: 256/258/260 (BrCl); measured molecular ion peak (M + H)+: 256/258/260 (BrCl); Rf value: 0.95 (silica gel, dichloromethane/methanol 9:1).
References
[1] Journal of Medicinal Chemistry, 1989, vol. 32, # 8, p. 1936 - 1942
[2] Synthesis, 2011, # 6, p. 934 - 942
[3] Patent: US2005/234101, 2005, A1. Location in patent: Page/Page column 14
[4] Patent: WO2005/103002, 2005, A2. Location in patent: Page/Page column 44-45
[5] Patent: US2005/267115, 2005, A1. Location in patent: Page/Page column 33
