[CH2:1]([N:5]([C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][C:19]=1[C:24]([F:27])([F:26])[F:25])[S:6]([C:9]1[CH:14]=[CH:13][C:12]([N+:15]([O-])=O)=[CH:11][CH:10]=1)(=[O:8])=[O:7])[CH:2]([CH3:4])[CH3:3].[Cl-].[NH4+]>CCO.O.[Fe]>[NH2:15][C:12]1[CH:13]=[CH:14][C:9]([S:6]([N:5]([CH2:1][CH:2]([CH3:4])[CH3:3])[C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][C:19]=2[C:24]([F:27])([F:25])[F:26])(=[O:8])=[O:7])=[CH:10][CH:11]=1A partial solution of N-isobutyl-4-nitro-N-(2-trifluoromethyl-phenyl)-benzenesulfonamide (1.68 g, 4.19 mmol), in EtOH (IMS grade, 50 mL) and water (15 mL) was treated with iron powder (˜325 mesh, 936 mg, 16.76 mmol) and ammonium chloride (896 mg, 16.76 mmol) and heated at reflux for 1 hour. The cooled mixture was filtered through diatomaceous earth washing the filter cake with EtOH and the filtrate concentrated to low volume under vacuum. The residue obtained was diluted with water and extracted into DCM. The combined extracts were dried over Na2SO4 and concentrated under vacuum. Purification by silica gel column chromatography (0-75% EtOAc in cyclohexane) gave 4-amino-N-isobutyl-N-(2-trifluoromethyl-phenyl)-benzenesulfonamide (1.53 g, 98%). 1H NMR (300 MHz, CDCl3) δ 7.72 (dd, J=7.5, 2.1 Hz, 1H), 7.54-7.39 (m, 4H), 7.14 (d, J=7.7 Hz, 1H), 6.70-6.63 (m, 2H), 3.35 (dd, J=13.5, 8.3 Hz, 1H), 3.15 (dd, J=13.5, 5.3 Hz, 1H), 1.71-1.55 (m, 1H), 0.88 (d, J=6.5 Hz, 3H), 0.77 (d, J=6.7 Hz, 3H). LCMS (m/z, Method A) ES+ 373.1 [M+1]+.
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