反应详情

To a stirred solution of the benzyl ester 10 (100 mg, 0.1968 mmol) in dry EtOAc-MeOH (3:1 ratio) (10 mL) was added 10% Pd/C (50 mg) and the resulting mixture stirred at room temperature under 1 atmosphere of hydrogen for 24 h. Filtration of the black Pd residue and evaporation of the filtrate gave a crude residue. Column chromatography on silica gel elution with 20% MeOH-EtOAc afforded (5S)-6-phenyl-5-[(tert-butyloxycarbonyl)-amino]-4-oxo-hexanoyl-L-proline 11a as a pale colourless oil (74 mg, 90%); Rf 0.23 (20% MeOH-EtOAc); IR (liquid film) ν 1720 (CO), 3000 (broad, COOH) cm−1; 1H NMR (300 MHz, CDCl3) δH 1.39 (9H, s, (CH3)3), 2.04 (2H, m, —CH2—), 2.44 (1H, br-s, —COOH), 2.62 (4H, m,), 2.94 (3H, m), 3.16 (1H, m), 3.60 (2H, m, —CH2N—), 4.52 (2H, m, 2×—CH—), 5.08 (1H, m, —NH—) and 7.14-7.35 (5H, m, Ar—H); 13C NMR (75 MHz, CDCl3) δC 21.0, 22.6, 24.7, 28.0, 29.2, 30.9, 31.4, 34.6, 46.9, 58.7, 60.4, 126.8, 127.0, 128.5, 128.7, 129.5, 136.4, 155.3, 171.8, 173.7, 207.5 and 208.0; HRMS m/z calcd for C22H30N2O6 (M+) 418.21734, found 418.21039.

1. filtrationFiltration of the black Pd residue and evaporation of the filtrate
2. customgave a crude residue
3. washColumn chromatography on silica gel elution with 20% MeOH-EtOAc