Phosphorus oxychloride → 8-Bromo-2-chloroquinoxaline

Participants

Reaction Conditions

Reaction Steps

A mixture of 8-bromoquinoxalin-2(1H)-one (483 mg, 2.146 mmol) in phosphoryl trichloride (100 mL) was heated to 50° C. for 2 h. The crude material was concentrated to remove the POCl3, diluted with EtOAc (150 ml), added to a separatory funnel, and washed with water (2×100 ml) and saturated aq. NaHCO3 (100 ml) before the organic layer was separated, dried over Na2SO4, and concentrated. The mixture and was adsorbed onto silica and was purified via automated flash chromatography (silica gel) with 100% hexanes to 5% EtOAc/hexanes to give 8-bromo-2-chloroquinoxaline (210e, 55% yield) as an off-white solid. MS (ESI, pos. ion) m/z: 243.0/245 (M+1).

Provenance & Evidence