[CH3:1][O:2][C:3]([C:5]1([C:8]2[CH:13]=[CH:12][C:11]([O:14][CH3:15])=[CH:10][CH:9]=2)[CH2:7][CH2:6]1)=[O:4].[N+:16]([O-])([OH:18])=[O:17].Cl>CC(OC(C)=O)=O.CC(O)=O>[CH3:1][O:2][C:3]([C:5]1([C:8]2[CH:9]=[CH:10][C:11]([O:14][CH3:15])=[C:12]([N+:16]([O-:18])=[O:17])[CH:13]=2)[CH2:6][CH2:7]1)=[O:4]
To a solution of 1-(4-methoxy-phenyl)-cyclopropanecarboxylic acid methyl ester (30.0 g, 146 mmol) in Ac2O (300 mL) was added a solution of HNO3 (14.1 g, 146 mmol, 65%) in AcOH (75 mL) at 0° C. The reaction mixture was stirred at 0-5° C. for 3 h before aq. HCl (20%) was added dropwise at 0° C. The resulting mixture was extracted with EtOAc (200 mL×3). The organic layer was washed with sat. aq. NaHCO3 then brine, dried over anhydrous Na2SO4 and evaporated under vacuum to give 1-(4-methoxy-3-nitro-phenyl)-cyclopropanecarboxylic acid methyl ester (36.0 g, 98%), which was directly used in the next step. 1H NMR (CDCl3, 300 MHz) δ7.84 (d, J=2.1 Hz, 1H), 7.54 (dd, J=2.1, 8.7 Hz, 1H), 7.05 (d, J=8.7 Hz, 1H), 3.97 (s, 3H), 3.65 (s, 3H), 1.68-1.64 (m, 2H), 1.22-1.18 (m, 2H).
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