C(O[C@H:5]1[CH2:9][N:8](C(OC(C)(C)C)=O)[C@@H:7]([C:17](O)=O)[CH2:6]1)C=C.Br[C:21]1[CH:22]=[C:23]([CH:27]=[C:28]([C:30]([O:32]C)=O)[CH:29]=1)[C:24]([OH:26])=[O:25].N(O[CH2:37]CCC)=O.C(OC(N1C[C@H](O)C[C@@H]1C(O)=O)=O)(C)(C)C>[Cu](Br)Br.O.C(#N)C>[CH2:7]([N:8]([CH2:9][CH2:5][CH3:6])[C:30]([C:28]1[CH:27]=[C:23]([CH:22]=[CH:21][CH:29]=1)[C:24]([OH:26])=[O:25])=[O:32])[CH2:17][CH3:37]
Step G (2): 3-bromo-5-(methoxycarbonyl)benzoic acid. To a mixture of copper (II) bromide (5.5 g, 24.6 mmol), n-butyl nitrite (3.17 g, 30.75 mmol) and acetonitrile (300 mL) was added 3-amino-5-(methoxycarbonyl)benzoic acid (Step G (1), 4.0 g, 20.5 mmol) in aceonitrile (300 mL) over 30 min at 0° C. and the mixture was warmed up and stirred at rt for 3 h. H2O was added and acetonitrile was removed. Ethyl acetate (600 mL) was added and the mixture was washed with 3N HCl, H2O, dried over Na2SO4, and concentrated in vacuo to give the title compound (97% yield): 1H NMR (CDCl3, 500 MHz) δ ppm 3.96 (3H, s), 8.41 (1H, s), 8.41 (1H, s), 8.67 (1H, m). MS (ESI) (M−H)− 259.02.
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