7-Bromo-2H-benzo[b][1,4]oxazin-3(4H)-one

38191-34-3

79-04-9

321436-06-0

2. 2-Amino-5-bromophenol (2.53 g, 18.2 mmol, 1.0 eq.) was dissolved in a solvent mixture of 15 mL of isobutylmethyl ketone and 15 mL of water, and cooled to 0 °C. Subsequently, NaHCO3 (3.67 g, 2.4 eq.) and chloroacetyl chloride (2.36 g, 1.67 mL, 1.15 eq.) were added. The reaction mixture was heated to reflux and stirred overnight, then cooled to room temperature. After completion of the reaction, the mixture was diluted with ethyl acetate, washed sequentially with water, dried with MgSO4 and finally concentrated under vacuum. Purification by silica gel column chromatography afforded 7-bromo-3,4-dihydro-2H-1,4-benzoxazin-3-one in 77% yield. After analyzed by low resolution mass spectrometry (LRMS), the molecular ion peak (M + H)+ was measured to be 180.1, which was consistent with the theoretical value of C9H10NO3.