Quinoxaline, 2-chloro-7-fluoro-

Synthesis

Synthesis of 2-chloro-7-fluoroquinoxaline: 7-fluoroquinolin-2(1H)-one (2.60 g, 15.84 mmol, 1.0 eq.) was mixed with phosphorochloridic acid chloride (50 mL, 536.4 mmol, 34.0 eq.) and the reaction was carried out at reflux for 1 hour. Upon completion of the reaction, the mixture was concentrated, diluted with water (60 mL) and the pH was adjusted with saturated aqueous sodium bicarbonate to 7. Subsequently, the reaction mixture was extracted with ethyl acetate (3 x 100 mL). The organic phases were combined, dried with anhydrous sodium sulfate, filtered and concentrated to give the crude product. The crude product was purified by column chromatography (silica gel, eluent: ethyl acetate/petroleum ether, 1:20, v/v) to afford 2-chloro-7-fluoroquinoxaline as a white solid (2.50 g, 84% yield).1H-NMR (400 MHz, DMSO-d6) δ ppm: 8.98 (s, 1H), 8.22 (dd, J = 2.0, 8.8 Hz, 1H ), 7.81-7.89 (m, 2H). ms m/z (+EI): 183.0 [M + H]+.

References

[1] Patent: WO2010/84152, 2010, A1. Location in patent: Page/Page column 55