(2S)-2-[(4-bromo-2-nitrophenyl)amino]butanoic acid → (3S)-7-bromo-3-ethyl-3,4-dihydroquinoxalin-2(1H)-one

Participants

Reaction Steps

A solution of (2S)-2-[(4-Bromo-2-nitrophenyl)amino]butanoic acid (8.3 g, 27.4 mmol) in methanol (20 mL) and acetic acid (20 mL) was treated with iron filings (5.0 g, 89.5 mmol). The reaction was heated at reflux for 3 h, after which time the reaction was cooled, and filtered. The filtrate was concentrated in vacuo, and the resulting residue was diluted with ethyl acetate, washed with a saturated aqueous solution of sodium bicarbonate, dried over magnesium sulfate, and concentrated in vacuo to yield 3.8 g (54%) of (3S)-7-bromo-3-ethyl-3,4-dihydroquinoxalin-2(1H)-one as a yellow solid. [α]D25=+33.23° (c=0.008 G/ML, DMSO); MS (ESI) m/z 255/257 ([M+H]+); Anal. Calcd for C10H11BrN2O: C, 47.08; H, 4.35; N, 10.98. Found: C, 46.98; H, 4.08; N, 10.90.

Provenance & Evidence