反应详情

To a stirred solution of ethyl-(5S)-5-[(N-benzoyl)amino]-4-oxo-6-phenyl-hexanoate (0.300 g, 0.8489 mmol, 1.0 eq) in THF-MeOH (8:2 ratio)(10 mL) was added 0.5N LiOH (10 mL) and the resulting mixture was stirred at room temperature for 3 h. The reaction mixture was then neutralized with glacial acetic acid and then extracted with EtOAc (3×25 mL). The organic extract was dried over anhydrous MgSO4 and evaporation of the solvent afforded a crude yellow residue. Column chromatography on silica gel elution with 100% EtOAc afforded (5S)-5-[(N-benzoyl)amino]-4-oxo-6-phenyl-hexanoic acid 4 as a white solid (0.232 g, 82%): mp 143-146° C. (lit.12 mp 142-143° C.); Rf 0.25 (EtOAc); IR (KBr) ν 1685 (CO), 1760 (CO), 3150 (COOH) cm−1; 1H NMR (400 MHz, CDCl3) δH 2.48 (2H, t, J=6.8 Hz, —CH2CO), 2.72 (2H, t, J=7.0 Hz, —CH2CO), 2.97 (1H, dd, J=6.4 and 14.4 Hz, —CHαPh), 3.18 (1H, dd, J=6.4 and 14.4 Hz, —CHβPh), 3.81 (2H, br s, —NH and —COOH), 4.87 (1H, t, J=6.8 Hz, —CH—) and 7.05-7.65 (10H, m, Ar—H); 13C NMR (100 MHz, CDCl3) δC 27.5, 34.9, 36.4, 59.5, 126.8, 126.9, 127.9, 128.4 (2C), 128.5 (2C), 129.1 (2C), 131.7, 133.5, 136.3, 167.9, 174.6 and 207.5; HRMS m/z calcd for C19H19NO4 (M+) 325.12854, found 353.13141.

1. extractionextracted with EtOAc (3×25 mL)
2. extractionThe organic extract
3. dry with materialwas dried over anhydrous MgSO4 and evaporation of the solvent
4. customafforded a crude yellow residue
5. washColumn chromatography on silica gel elution with 100% EtOAc