[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH:11]2[CH:16]([N+:17]([O-])=O)[CH2:15][CH2:14][CH:13]([O:20][C:21](=[O:23])[CH3:22])[CH2:12]2)[CH:6]=[CH:7][C:8]=1[O:9][CH3:10].O>C(O)C.C(O)(=O)C.[Cu].[Zn].[Zn].O.C([O-])(=O)C.[Cu+2].C([O-])(=O)C>[NH2:17][CH:16]1[CH2:15][CH2:14][CH:13]([O:20][C:21](=[O:23])[CH3:22])[CH2:12][CH:11]1[C:5]1[CH:6]=[CH:7][C:8]([O:9][CH3:10])=[C:3]([O:2][CH3:1])[CH:4]=1
A solution of 10.37 g of acetic acid (1RS,3RS,4RS)-3-(3,4-dimethoxyphenyl)-4-nitrocyclohexyl ester (compound C2) in 240 ml of ethanol is added to a zinc-copper couple, prepared from 16.8 g of zinc powder and 920 mg of copper (II) acetate monohydrate in acetic acid, the resulting suspension is refluxed and treated with 26 ml of acetic acid, 3.2 ml of water and 26 ml of ethanol. The resulting mixture is refluxed for further 15 min. The precipitate is filtered off with suction and the solvent is removed. Chromatographical purification on silica gel using a mixture of petroleum ether/ethyl acetate/triethylamine in the ratio 2/7/1 and concentration of the corresponding eluate fractions afford 5.13 g (55% of theory) of the title compound as a pale brown oil.
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