Dimethylformamide → 5-Chloro-3-(3-fluorophenyl)quinoxaline-2-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

A mixture of 2-(bromomethyl)-5-chloro-3-(3-fluorophenyl)quinoxaline (Prepared in Example 95, 0.8089 g, 2.301 mmol) and sodium metaperiodate (0.9842 g, 4.601 mmol) in DMF (15.34 mL, 2.301 mmol) was heated at 150° C. with stirring. After 5 h, the mixture was cooled to room temperature, diluted with EtOAc (100 mL), washed with sat'd Na2S2O3 (50 mL×1) and brine (50 mL×2), dried over Na2SO4, filtered, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography on a 80 g of Redi-Sep™ column using 0 to 10% gradient of EtOAc in hexane over 10 min, then 10% isocratic of EtOAc for 20 min, then 10 to 20% gradient of EtOAc in hexane over 20 min, then 20% isocratic of EtOAc for 20 min as eluent to give 5-chloro-3-(3-fluorophenyl)quinoxaline-2-carbaldehyde as a solid: 1H NMR (400 MHz, DMSO-d6) δ ppm 10.18 (1 H, s), 8.31 (1 H, dd, J=8.2, 1.2 Hz), 8.25 (1 H, dd, J=7.4, 1.2 Hz), 7.99 (1 H, dd, J=8.4, 7.6 Hz), 7.56-7.70 (3 H, m), 7.38-7.46 (1 H, m); LC-MS (ESI) m/z 287.0 [M+H]+.

Provenance & Evidence