[CH3:1][O:2][C:3]1[CH:4]=[C:5](Br)[C:6]([N+:11]([O-])=O)=[CH:7][C:8]=1[O:9][CH3:10].[CH3:15][O:16][C:17]1[CH:18]=[C:19](Br)[CH:20]=[CH:21][C:22]=1[O:23][CH3:24].[N+]([O-])(O)=O>C(O)(=O)C>[CH3:15][O:16][C:17]1[C:22]([O:23][CH3:24])=[CH:21][C:20]2[C:8]3[CH:7]=[N:11][C:6]4[CH:7]=[C:8]([O:9][CH3:10])[C:3]([O:2][CH3:1])=[CH:4][C:5]=4[C:3]=3[CH:4]=[CH:5][C:19]=2[CH:18]=13,4-Dimethoxy-6-nitro-bromobenzene (16). 3,4-Dimethoxybromobenzene (5 g, 23 mmol) was slowly added to a stirred solution of 35 mL concentrated nitric acid and 105 mL glacial acetic acid maintained at 10° C. The reaction mixture was stirred at 15° C. for 1 h and then diluted with 200 mL ice cold water. The resulting mixture was extracted thrice with 200 mL portions of ether. The combined organic phase was dried and evaporated in vacuo. The crude product was recrystallized from ethanol to give bright yellow needle shaped crystals of compound 16 in 92% yield; mp=122-124° C.; IR (Nujol) 1510, 1312; 1H NMR δ 3.94 (3H, s), 3.97 (3H, s), 7.12 (1H, s), 7.57 (1H, s); 13C NMR δ 56.9, 57.2, 108.0, 109.5, 117.0, 148.7, 153.3; Anal. calcd for C8H8NO4Br: C, 36.72, H, 3.14, N, 5.30; Found: C, 36.70, H, 3.13, N, 5.29.
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