[Br:1][C:2]1[CH:3]=[C:4]([CH:18]=[C:19]([N+:21]([O-])=O)[CH:20]=1)[C:5]([NH:7][CH2:8][CH2:9][O:10][CH2:11][CH2:12][O:13][CH2:14][CH2:15][O:16][CH3:17])=[O:6].Cl>CCO.O.[Fe]>[NH2:21][C:19]1[CH:18]=[C:4]([CH:3]=[C:2]([Br:1])[CH:20]=1)[C:5]([NH:7][CH2:8][CH2:9][O:10][CH2:11][CH2:12][O:13][CH2:14][CH2:15][O:16][CH3:17])=[O:6]Iron powder (5.90 g, 106 mmol) was added to a solution of the product from step (i) above (8.24 g, 20.43 mmol) and concentrated HCl (2 mL, 23.40 mmol) in EtOH (65 mL) and water (15 mL). The mixture was heat at 75° C. (block temperature) for 1 h. Then, the reaction was cooled to rt, before being diluted with water (30 mL), filtered and concentrated in vacuo. The residue was basified (NaHCO3) then partitioned between EtOAc (350 mL) and water (275 mL). The organic layer was dried (MgSO4), filtered and concentrated in vacuo to afford an orange oil that was purified by chromatography on silica gel (220 g column, 0-5% MeOH in DCM) to afford the sub-title compound (5.25 g) as an orange oil.
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