(2S)-2-amino-3-(2-nitrophenyl)propanoic acid → (3S)-3-Amino-3,4-dihydro-1-hydroxy-2(1H)-quinolinone

Participants

Reaction Steps

L-2-Nitrophenylalanine (C11) (419.6 mg, 2.0 mmol) was dissolved in methanol (23.8 mL) and water (240 μL). Concentrated aqueous HCl (2-4 drops) was added to aid solubility. Platinum on carbon (42 mg) was added and the reaction was hydrogenated on a Parr shaker at 10 psi for 1 hour, whereupon the reaction was filtered through Celite. The catalyst was washed with a 1 N solution of ammonium hydroxide in methanol and then with methanol. The filtrate was concentrated to provide a crude product, which was subsequently dry packed with a minimum amount of silica, using a methanol/dichloromethane solution to dissolve the material. Purification using silica gel chromatography (Gradient: 0% to 20% methanol (containing 1% ammonium hydroxide) in dichloromethane) provided Example 4 as a solid (207 mg, 58%). APCI m/z 179.1 (M+1). 1H NMR (400 MHz, CD3OD) δ 2.88 (dd, J=14, 15 Hz, 1H), 3.09 (dd, J=15.3, 6.2 Hz, 1H), 3.67 (dd, J=13.6, 6.1 Hz, 1H,) 7.06 (ddd, J=7.2, 7.2, 1.7 Hz, 1H), 7.23 (br d, J=7.5 Hz, 1H), 7.27-7.34 (m, 2H).

Provenance & Evidence