[CH3:1][O:2][CH2:3][CH2:4][NH:5][S:6]([CH2:9][C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1)(=[O:8])=[O:7].[C:16](OCC)(=[O:22])[C:17](OCC)=[O:18].CC(C)([O-])C.[K+]>CN(C=O)C>[OH:22][C:16]1[C:17](=[O:18])[N:5]([CH2:4][CH2:3][O:2][CH3:1])[S:6](=[O:7])(=[O:8])[C:9]=1[C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1A solution of N-(2-methoxyethyl)-1-phenylmethanesulfonamide (3.5 g, 14.5 mmol) and diethyl oxalate (2.33 g, 16.0 mmol) in dry DMF was cooled in an ice-bath. Potassium tert-butoxide (2.17 g, 18.4 mmol) was added and after 5 mins the ice-bath was removed and the reaction was stirred at rt for 22 h. 2M HCl (45 mL) was added to the mixture and the acidic solution was extracted 3 times with dichloromethane. The combined organic layers were washed 4 times with water, dried through a phase separator and evaporated. The residue was purified by preparative HPLC [0.1M NH4OAc/MeCN, (9:1 to 1:9)] to give the title compound (0.250 g, 6%) as a solid; 1H NMR (500 MHz, CD3OD): δ 7.90-7.94 (m, 2H), 7.28-7.33 (m, 2H), 7.10-7.15 (m, 1H), 3.79 (t, 2H), 3.68 (t, 2H), 3.34 (s, 3H); Mass Spectrum: M−H+ 282.
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