[CH2:1]([C:6]1[CH:11]=[CH:10][C:9]([NH:12][C:13](=[O:15])[CH3:14])=[CH:8][CH:7]=1)[C:2]([CH3:5])([CH3:4])[CH3:3].[N+:16]([O-])([OH:18])=[O:17].O>C(OC(=O)C)(=O)C>[CH2:1]([C:6]1[CH:7]=[CH:8][C:9]([NH:12][C:13](=[O:15])[CH3:14])=[C:10]([N+:16]([O-:18])=[O:17])[CH:11]=1)[C:2]([CH3:5])([CH3:4])[CH3:3]To a suspension of N-(4-neopentylphenyl)acetamide (Preparation 98, 2.54 g, 12.4 mmol) in acetic anhydride (20 mL) cooled in an ice bath was added a solution of nitric acid (0.78 mL, 18 mmol) in acetic anhydride (5 mL) dropwise. The solution was allowed to warm to room temperature for 18 hours. The yellow solution was added to water and extracted with dichloromethane (3×). The organic layers were dried over anhydrous magnesium sulphate, filtered, and concentrated in vacuo. The residue was purified using silica gel column chromatography eluting with a 0-50% ethyl acetate/hexanes gradient to provide the title compound (3.0 g, 97%) as a yellow oil.
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