[CH2:1]([NH:3][C:4](=[O:15])[C:5]1[CH:10]=[CH:9][CH:8]=[CH:7][C:6]=1[Si:11]([CH3:14])([CH3:13])[CH3:12])[CH3:2].[N+:16]([O-])([OH:18])=[O:17].S(=O)(=O)(O)O>C(Cl)Cl>[CH2:1]([NH:3][C:4](=[O:15])[C:5]1[CH:10]=[C:9]([N+:16]([O-:18])=[O:17])[CH:8]=[CH:7][C:6]=1[Si:11]([CH3:14])([CH3:13])[CH3:12])[CH3:2]To a solution of the amide of example 49 (1.10 g, 5 mmol) in CH2Cl2 (50 mL) at 0° C. was added dropwise over 2 min, a cold mixture of 70% nitric acid (0.95 mL, 15 mmol) and concentrated sulfuric acid (5 mL) dropwise. The mixture was stirred at 0° C. for 10 min and was poured onto ice. The mixture was extracted with ethyl acetate, the combined organic layers washed with brine, sat NaHCO3, brine, dried (MgSO4) and concentrated to a solid (2.68 g, 101%) consisting of a 2:1 ratio of 5-nitro and 3-nitro isomers. The title compound was obtained by RC (ethyl acetate/hexanes) in 60% yield as a white solid. m.p. 100-102° C.
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