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

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.

1. filtrationfiltered over a pad of celite
2. washrinsed with ethyl acetate (80 mL)
3. washThe filtrate was successively washed with water (2×30 mL)
4. dry with materiala saturated aqueous solution of sodium bicarbonate (40 mL), then dried over anhydrous magnesium sulfate
5. filtrationfiltered
6. concentrationconcentrated to dryness under reduced pressure
7. customwithout purification

ORD record

ord-b6a7fdbd3ab84a0d8700a9f8573e9aa6

Source dataset

uspto-grants-2014_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08637507B2