[C:1]([O:5][C:6]([NH:8][C@@H:9]([C:14]([O:16][CH2:17][C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1)=[O:15])[CH2:10][CH2:11][CH2:12][OH:13])=[O:7])([CH3:4])([CH3:3])[CH3:2].CO[C:26](OC)([CH3:28])[CH3:27].CC1C=CC(S([O-])(=O)=O)=CC=1.C1C=C[NH+]=CC=1.O>C1COCC1>[CH3:27][C:26]1([CH3:28])[N:8]([C:6]([O:5][C:1]([CH3:4])([CH3:2])[CH3:3])=[O:7])[C@@H:9]([C:14]([O:16][CH2:17][C:18]2[CH:19]=[CH:20][CH:21]=[CH:22][CH:23]=2)=[O:15])[CH2:10][CH2:11][CH2:12][O:13]1To the solution of benzyl N-(tert-butoxycarbonyl)-5-hydroxy-D-norvalinate (Preparation 50, 3 g, 9.28 mmol) in THF (20 mL) was added 2,2-dimethoxypropane (12.07 mL, 92.8 mmol) and PPTS (catalytic amount), and the reaction was stirred for 5 hours at 60° C. The reaction mixture was poured into cold water and extracted with EtOAc. The organic layer was dried over Na2SO4 and concentrated under reduced pressure to afford the title compound (2.5 g, 74%).
불러오는 중…