OS(O)(=O)=O.Cl.[CH3:7][C:8]1([CH3:17])[C:16]2[C:11](=[CH:12][CH:13]=[CH:14][CH:15]=2)[NH:10][CH2:9]1.[N+:18]([O-])([OH:20])=[O:19].[NH4+].[OH-]>O>[CH3:7][C:8]1([CH3:17])[C:16]2[C:11](=[CH:12][C:13]([N+:18]([O-:20])=[O:19])=[CH:14][CH:15]=2)[NH:10][CH2:9]1H2SO4 (1.42 kg) and 3,3-dimethylindoline HCl salt (Example 3, 200 g) were charged to a dry 5 L RB-flask under nitrogen at 20-25° C. The reaction mixture was cooled to −15 to 10° C. A solution of HNO3 (75.6 g) in water (18.89 g) was added drop-wise. The resulting reaction mixture was stirred for 1 h. The mixture was transferred into a mixture of 2.084 L of 30% NH4OH and 600 mL of water at 0-5° C. The pH was adjusted to 8-9 with NH4OH, and after the addition of 800 mL of IPAC, phases were separated. The aqueous phase was extracted with IPAC (400 mL). The combined organic phase was washed with saturated brine (400 mL) to give a solution of 3,3-dimethyl-6-nitroindoline. (190.5 g, 91%, 94 A %).
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