[CH2:1]([O:4][N:5]([C@H:18]1[CH2:23][N:22](C(OC(C)(C)C)=O)[C@H:21]([CH2:31][O:32][CH3:33])[CH:20]=[C:19]1[C:34](=[O:37])[NH:35][CH3:36])[S:6]([C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[N+:15]([O-:17])=[O:16])(=[O:8])=[O:7])[CH:2]=[CH2:3].Cl>O1CCOCC1>[CH2:1]([O:4][N:5]([C@@H:18]1[C:19]([C:34]([NH:35][CH3:36])=[O:37])=[CH:20][C@@H:21]([CH2:31][O:32][CH3:33])[NH:22][CH2:23]1)[S:6]([C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[N+:15]([O-:17])=[O:16])(=[O:8])=[O:7])[CH:2]=[CH2:3]To a solution of (2S,5R)-tert-butyl 5-(N-(allyloxy)-2-nitrophenylsulfonamido)-2-(methoxymethyl)-4-(methylcarbamoyl)-5,6-dihydropyridine-1(2H)-carboxylate (Intermediate 256, 1 g, 1.85 mmol) in dioxane (10 ml) at room temperature was added 4M HCl in Dioxane (2 ml, 57.16 mmol). The reaction mixture was stirred at that temperature for 4-5 hours. The reaction mixture was concentrated and the crude was taken up in 2M NaOH and extracted with dichloromethane. The combined organic extracts were washed with brine, dried over sodium sulfate, filtered and concentrated. Silica gel chromatography (increasing percentage of methanol in dichloromethane) afforded the title compound as a thick oil (0.56 g, 69%).
読み込み中…