[H-].[Na+].[Cl:3][C:4]1[CH:5]=[C:6]([NH:11][C:12](=[O:15])[O:13][CH3:14])[CH:7]=[CH:8][C:9]=1[OH:10].Br[CH2:17][C:18]1[S:19][C:20]2[CH:26]=[CH:25][CH:24]=[CH:23][C:21]=2[N:22]=1.[Cl-].[NH4+]>CN(C)C=O>[S:19]1[C:20]2[CH:26]=[CH:25][CH:24]=[CH:23][C:21]=2[N:22]=[C:18]1[CH2:17][O:10][C:9]1[CH:8]=[CH:7][C:6]([NH:11][C:12](=[O:15])[O:13][CH3:14])=[CH:5][C:4]=1[Cl:3]44.4 mg of sodium hydride (as a 60% w/w dispersion in mineral oil) were added to a solution of 203.6 mg of methyl N-(3-chloro-4-hydroxyphenyl)carbamate [prepared as described in step (a) above] in 4 ml of dimethylformamide cooled in an ice-water bath. The resulting mixture was stirred at the same temperature for 3 minutes, and then 241.9 mg of 2-bromomethylbenzothiazole were added. The temperature of the reaction mixture was then elevated to room temperature and the mixture was stirred for 1.5 hours. At the end of this time, a saturated aqueous ammonium chloride solution was added to the reaction mixture and the resulting mixture was extracted with ethyl acetate. The resulting extract was washed consecutively with water and a saturated aqueous sodium chloride solution and then dried over anhydrous sodium sulfate. The solvent was removed by evaporation under reduced pressure to give a crude crystalline solid which was purified by column chromatography through silica gel using a 2:1 by volume mixture of hexane and ethyl acetate as the eluent, to give 286.9 mg (yield 81%) of the title compound as a solid having a melting point of 133°-135° C.
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