Potassium Carbonate → 3-(2-Bromopyridin-3-yl)-5-nitro-3,4-dihydro-2H-1,4-benzoxazin-3-ol

Participants

Reaction Conditions

Reaction Steps

A solution of 2-bromo-1-(2-bromopyridin-3-yl)ethanone (2.15 g, 7.71 mmol) in methylene chloride (77.1 mL) and water (19.3 mL) was treated with potassium carbonate (2.13 g, 15.4 mmol), tetra-N-butylammonium bromide (500 mg, 1.50 mmol), and 2-amino-3-nitrophenol (1.31 g, 8.48 mmol), and heated at 40° C. for 5 h. The reaction mixture was then diluted with brine. The aqueous layer was separated and extracted with dichloromethane (2×100 mL). The combined organic layers were washed with water and brine, dried over magnesium sulfate, filtered, and concentrated to give the crude product. Purification by flash column chromatography (100% hexanes to 35% ethyl acetate/hexanes) gave the desired product (2.45 g, 90%) as a racemic mixture. LCMS calculated for C13H11BrN3O4 (M+H)+: m/z=352.0, 354.0. found: 351.7, 353.8.

Provenance & Evidence