[N+:1]([C:4]1[CH:5]=[CH:6][C:7]2[CH2:12][CH2:11][O:10][B:9]([OH:13])[C:8]=2[CH:14]=1)([O-])=O.CCN(CC)CC.[Cl:22][C:23]1[CH:28]=[CH:27][C:26]([S:29](Cl)(=[O:31])=[O:30])=[CH:25][CH:24]=1>C1COCC1.CCOC(C)=O.[Pd]>[Cl:22][C:23]1[CH:28]=[CH:27][C:26]([S:29]([NH:1][C:4]2[CH:5]=[CH:6][C:7]3[CH2:12][CH2:11][O:10][B:9]([OH:13])[C:8]=3[CH:14]=2)(=[O:31])=[O:30])=[CH:25][CH:24]=1A solution of 7-nitro-3,4-dihydro-benzo[c][1,2]oxaborinin-1-ol (694.6 mg, 3.6 mmol) in THF (70 mL) was passed through H-cube equipped with a 10% Pd/C cartridge. The collected light yellow solution was treated with Et3N (0.6 mL, 4.3 mmol, 1.2 eq.) and divided evenly into 12 portions. To a portion of the solution was added 4-chloro-benzenesulfonyl chloride (63.3 mg, 0.29 mmol). The resulting mixture was stirred at room temperature overnight. The reaction solution was diluted with EtOAc (20 mL), washed with 1N HCl (10 mL), H2O (10 mL), brine (10 mL) and concentrated under reduced pressure. The residue was dissolved in minimal amount of THF and then titrated with heptanes to vive a white suspension. The precipitate was collected by filtration, washed with heptanes to give the title compound as a white solid. LCMS (M/Z): 338 (M+H); 1H NMR (DMSO-d6) δ: 10.17 (s, 1H), 8.39 (s, 1H), 7.65-7.70 (m, 2H), 7.56-7.61 (m, 2H), 7.32 (d, J=1.8 Hz, 1H), 7.02-7.08 (m, 2H), 3.96 (t, J=5.9 Hz, 2H), 2.72 (t, J=5.9 Hz, 2H).
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