(R)-methyl 2-(5-bromo-2-nitrophenoxy)propanoate → (R)-7-bromo-2-methyl-2H-benzo[b][1,4]oxazin-3(4H)-one

Participants

Reaction Steps

Iron powder (1.91 g, 34.15 mmol) and (R)-methyl 2-(5-bromo-2-nitrophenoxy)propanoate (R)-A-16 (525.0 mg, 1.71 mmol) were heated at 50° C. in glacial acetic acid (10.5 mL) for 5 h. The reaction mixture was cooled to room temperature, diluted with ethyl acetate (80 mL), filtered over a pad of celite, and rinsed with ethyl acetate (80 mL). The filtrate was successively washed with water (2×30 mL), a saturated aqueous solution of sodium bicarbonate (40 mL), then dried over anhydrous magnesium sulfate, filtered and concentrated to dryness under reduced pressure. The resulting white crystalline solid (R)-7-bromo-2-methyl-2H-benzo[b][1,4]oxazin-3(4H)-one (R)-A-17 (399.4 mg, Yield=96%) was used as such for next step without purification. MS (ESI) [M+1]+ 242, 244.

Provenance & Evidence