[CH3:1][S:2]([O-:4])=[O:3].[Na+].Br[C:7]1[C:8]([N+:14]([O-:16])=[O:15])=[C:9]([CH:11]=[CH:12][CH:13]=1)[NH2:10].CCN(C(C)C)C(C)C.CS(C)=O>CCOC(C)=O.[O-]S(C(F)(F)F)(=O)=O.[Cu+2].[O-]S(C(F)(F)F)(=O)=O>[CH3:1][S:2]([C:7]1[C:8]([N+:14]([O-:16])=[O:15])=[C:9]([CH:11]=[CH:12][CH:13]=1)[NH2:10])(=[O:4])=[O:3]
To a mixture of copper(II) triflate (0.83 g, 2.3 mmol), sodium methanesulfinate (2.8 g, 27.6 mmol), 3-bromo-2-nitroaniline (5.0 g, 23 mmol) under N2, was added DIEA (0.50 mL, 4.6 mmol) and DMSO (10 mL). The stirred mixture was heated in a pre-heated 110° C. oil bath for 18 h. The mixture was cooled to rt, diluted with EtOAc, and filtered through a pad of Celite™. The filtrate was washed with water, brine, dried and concentrated in vacuo. Purification of the residue by flash chromatography over silica gel, using 0 to 10% gradient of MeOH in DCM with 0.2% NH4OH as eluent gave 3-(methylsulfonyl)-2-nitroaniline: 1H NMR (400 MHz, CDCl3) δ 7.44 (1H, dd, J=8.0, 4.0 Hz), 7.35 (1H, t, J=8.0 Hz), 7.02 (1H, dd, J=8.0, 4.0 Hz), 5.04 (2H, br), 3.36 (3H, s); LC-MS (ESI) m/z 217.0 [M+H]+.
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