Tetrahydrofuran → HCID 89484872, Verbindung

To a solution of tert-butyl(2,4-difluorophenyl) carbonate (2.21 g, 9.6 mmol, 1.2 eq.) in THF (150 mL) cooled at −78° C. was added n-BuLi (3.84 mL, 9.6 mmol, 1.2 eq.) dropwise. The resulting mixture was stirred at −78° C. for 30 min, then a solution of 3-chloro-N-methoxy-N-methylquinoxaline-6-carboxamide (2.0 g, 9.6 mmol, 1.0 eq.) in THF (50 mL) was added dropwise. The resulting mixture was stirred at −78° C. for 1 h, then quenched by the addition of NH4Cl solution. The mixture was extracted with EA (100 mL×3). The combined organic layers were dried over Na2SO4, filtered and concentrated. The residue was purified via flash column chromatography (PE/EA=4/1, v/v) to afford tert-butyl (3-(3-chloroquinoxaline-6-carbonyl)-2,4-difluorophenyl) carbonate as a yellow oil (240 mg, 7%).