[NH2:1][S:2]([C:5]1[CH:16]=[CH:15][CH:14]=[CH:13][C:6]=1[C:7]([O:9][CH2:10][CH2:11][OH:12])=[O:8])(=[O:4])=[O:3].C(Cl)Cl.[CH3:20][Si:21](Cl)([CH3:23])[CH3:22]>C(N(CC)CC)C>[NH2:1][S:2]([C:5]1[CH:16]=[CH:15][CH:14]=[CH:13][C:6]=1[C:7]([O:9][CH2:10][CH2:11][O:12][Si:21]([CH3:23])([CH3:22])[CH3:20])=[O:8])(=[O:3])=[O:4]To a slurry of 12.25 g of 2-aminosulfonylbenzoic acid, 2-hydroxyethyl ester, 125 ml of dry methylene chloride, and 7.7 ml of triethylamine was added dropwise over 10 minutes 6.3 ml of trimethylsilyl chloride (exotherm to 36° C.). The resulting solution was allowed to stand at ambient temperature for 18 hours and then washed with saturated sodium chloride solution, dried (MgSO4), and the solvent removed under reduced pressure to give an oil which was chromatographed on silica gel eluting with 25% EtOAc:hexane to give a colorless oil which slowly crystallized. Trituration with hexane gave 8.0 g of white crystals, m.p. 72°-76° C.
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