[N+:1]([O-:4])([O-])=[O:2].[K+].[CH3:6][C:7]1([CH3:18])[CH2:13][CH2:12][CH2:11][NH:10][C:9]2[CH:14]=[CH:15][CH:16]=[CH:17][C:8]1=2.C([O-])(O)=O.[Na+]>OS(O)(=O)=O>[CH3:6][C:7]1([CH3:18])[CH2:13][CH2:12][CH2:11][NH:10][C:9]2[CH:14]=[C:15]([N+:1]([O-:4])=[O:2])[CH:16]=[CH:17][C:8]1=2At 0° C., KNO3 (0.76 g, 7.54 mmol) was added portionwise to a solution of 5,5-dimethyl-2,3,4,5-tetrahydro-1H-benzo[b]azepine (1.1 g, 6.28 mmol) in H2SO4 (15 mL). After stirring 15 min at this temperature, the mixture was poured into ice water, basified with sat. NaHCO3 to pH 8 and extracted with EtOAc. The organic layer was washed with brine, dried over Na2SO4 and concentrated to give crude 5,5-dimethyl-8-nitro-2,3,4,5-tetrahydro-1H-benzo[b]azepine (1.2 g), which was used directly in the next step without further purification.
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