Synthesis
GENERAL PROCEDURE: 3-methylquinoxalin-2-ol (28.1 mmol, 5.0 g) was dissolved in phosphorous trichloride (POCl3, 25 mL) at 0°C and the resulting solution was allowed to reflux at 120°C for 5 hours. Upon completion of the reaction, the reaction was quenched with a cooled ammonia solution and extracted with ethyl acetate (EtOAc, 2 x 15 mL). The organic phase was separated and washed with saturated sodium chloride solution, dried over anhydrous magnesium sulfate (MgSO4), filtered, and concentrated in vacuum to give the crude product. The crude product was purified by silica gel fast column chromatography (eluent: petroleum ether/ethyl acetate = 10:1, v/v) to afford 5.0 g 3-methyl-2-chloro-quinoxaline as an off-white solid in 90% yield. Melting point: 86.0-87.0 °C; ESI-MS m/z: 179.4 [M + H]+.
References
[1] European Journal of Medicinal Chemistry, 2016, vol. 124, p. 311 - 325
[2] European Journal of Medicinal Chemistry, 2009, vol. 44, # 3, p. 1135 - 1143
[3] Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 2001, vol. 40, # 7, p. 565 - 573
[4] E-Journal of Chemistry, 2011, vol. 8, # 2, p. 635 - 642
[5] Journal of Heterocyclic Chemistry, 2007, vol. 44, # 5, p. 1139 - 1143
