[C:1]([O:4][CH2:5][C:6]1[C:11]([F:12])=[CH:10][C:9](N)=[CH:8][C:7]=1[Cl:14])(=[O:3])[CH3:2].[N:15]([O-])=O.[Na+].[O-:19][S:20]([O-:22])=O.[Na+].[Na+]>CN(C=O)C.Cl>[C:1]([O:4][CH2:5][C:6]1[C:11]([F:12])=[CH:10][C:9]([S:20](=[O:22])(=[O:19])[NH2:15])=[CH:8][C:7]=1[Cl:14])(=[O:3])[CH3:2]
To a solution of 4-amino-2-chloro-6-fluorobenzyl acetate (5.2 g, 0.024 mol) in DMF (10 mL) at 0° C. was added slowly 3M HCl (100 mL) followed by NaNO2 (2 g, 0.029 mol). After stirring at the same temperature for 20 min, the mixture was added dropwise to a solution of Na2SO3 (12 g, 0.096 mol) and CuSO45H2O in 3N HCl (100 mL). After stirring for 30 min, the reaction mixture was then poured into ice-water and extracted with EtOAc. The combined extracts were concentrated, dried over anhydrous MgSO4, filtered and concentrated in vacuo. The material was dissolved in THF and added dropwise to a stirred solution of NH4OH (17 mL) in THF (17 mL) at 5° C. After stirring 30 min, the mixture was concentrated under reduced pressure and extracted with EtOAc. The combined extracts were washed with H2O, dried over anhyd MgSO4, concentrated and purified by column chromatography (Hex/EtOAc=5:1) to afford 2-chloro-6-fluoro-4-sulfamoylbenzyl acetate (1.02 g, 15%, 3 steps) as an orange solid. 1H NMR (400 MHz, CDCl3) δ 7.80 (t, 1H), 7.59 (dd, 1H), 5.28 (d, 2H), 5.16 (s, 2H), 2.10 (d, 3H); MS (EI) m/z 303 (M+Na+).
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