1829-34-1

33491-30-4

3-Bromo-2-hydroxybenzaldehyde (402 mg, 2.0 mmol) was used as starting material and dissolved in N-methylpyrrolidone (NMP, 5 mL). Subsequently, ethoxymethylene triphenylphosphine (765 mg, 2.2 mmol) was added to this solution. The reaction mixture was heated at 210 °C for 3 hours. Upon completion of the reaction, the mixture was cooled to room temperature and subsequently partitioned between water and ethyl acetate. The organic and aqueous layers were separated and the organic layer was dried with anhydrous magnesium sulfate (MgSO?). The product was purified by rapid column chromatography on silica gel (eluent ratio 2:1 hexane/ethyl acetate), resulting in 8-bromo-2H-1-benzopyran-2-one (116 mg, 26% yield) as a light beige solid. The mass spectrum (electrospray ionization, ES) showed m/e of 227.0 ([M + H]+).