Br[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[S:8]([CH3:11])(=[O:10])=[O:9].[NH:12]1[CH2:17][CH2:16][NH:15][CH2:14][CH2:13]1>>[CH3:11][S:8]([C:3]1[CH:4]=[CH:5][CH:6]=[CH:7][C:2]=1[N:12]1[CH2:17][CH2:16][NH:15][CH2:14][CH2:13]1)(=[O:10])=[O:9]A mixture of 2-bromo(methylsulfonyl)benzene (1.10 g, 4.7 mmol) and anhydrous piperazine (2.02 g, 23.5 mmol) was heated at 110° C. overnight. Then, the mixture was cooled and partitioned between 2 N NaOH and CH2Cl2. The separated organic layer was dried over Na2SO4 and concentrated under reduced pressure. The crude residue was chromatographed (CHCl3/CH3OH, 9:1, as eluent) to give 8 as a white semisolid (0.36 g, 34% yield). 1H NMR: δ 2.58 (s, 1H, NH, D2O exchanged), 2.84 (s, 4H, piperazinic), 3.14 (s, 3H, CH3), 7.10-7.83 (m, 4H, aromatic).
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