[Cl:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=2)[C:3]=1[S:14]([NH:17]C(C)(C)C)(=[O:16])=[O:15].O>FC(F)(F)C(O)=O>[Cl:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=2)[C:3]=1[S:14]([NH2:17])(=[O:16])=[O:15]A solution of 2-chloro-N-(1,1-dimethylethyl)-6-phenylbenzenesulfonamide (23 g, 0.071 mol) in a mixture of 120 ml trifluoroacetic acid (TFA) plus 4 ml water was heated to reflux for 2 hours. The TFA was evaporated in vacuo and the residue partitioned between methylene chloride and water. The organic layer was dried (MgSO4), evaporated, and the residue crystallized from ether/methylene chloride to afford 15.9 g of crystalline solid in two crops, m.p. 185°-87°. NMR (90 MHZ, CDCl3) 6.45 (s, br, NH2). 7.3-7.7 (m, 8H) ppm.
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