[C:1]([O:5][C:6]([NH:8][C@@H:9]([CH2:14][CH2:15][CH2:16][C:17]([CH3:22])([N+:19]([O-])=O)[CH3:18])[C:10]([O:12][CH3:13])=[O:11])=[O:7])([CH3:4])([CH3:3])[CH3:2].[H][H]>CO.O.[C].[Pd]>[CH3:13][O:12][C:10](=[O:11])[C@H:9]([CH2:14][CH2:15][CH2:16][C:17]([CH3:22])([CH3:18])[NH2:19])[NH:8][C:6]([O:5][C:1]([CH3:4])([CH3:2])[CH3:3])=[O:7]Methyl (S)-2-t-butoxycarbonylamino-6-methyl-6-nitroheptanoate (500 mg, 1.57 mmol) was dissolved in methanol (8 ml) and water (0.5 ml), and 5% palladium-carbon (219 mg, 50% wet) and ferrous sulfate 7 hydrate (1.32 g, 4.75 mmol) were added. The mixture was stirred at a hydrogen pressure of 3 atm and room temperature for 3 h. Palladium-carbon was removed by filtration and methanol was evaporated by concentration under reduced pressure. Ethyl acetate (50 ml), water (50 ml) and sodium carbonate were added for pH adjustment to 10 and extraction. After layer partitioning, the aqueous layer was extracted again with toluene-isopropyl alcohol (1:1, 100 ml). The organic layers were combined and the solvent was evaporated by concentration under reduced pressure to give the objective compound (350 mg, yield 77.3%).
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