[C:1]([NH:4][C:5]1[S:6][C:7]([Cl:10])=[CH:8][N:9]=1)(=[O:3])[CH3:2].[H-].[Na+].[CH3:13][O:14][CH2:15][CH2:16]Br>C1COCC1.CN(C=O)C.C(OCC)(=O)C>[Cl:10][C:7]1[S:6][C:5](=[N:4][C:1](=[O:3])[CH3:2])[N:9]([CH2:16][CH2:15][O:14][CH3:13])[CH:8]=1A flask was charged with 2-acetamido-5-chlorothiazole (Lancaster, 19.3 g, 110 mmol) in 200 mL of 2:1 THF/DMF. To the solution was added sodium hydride (60% dispersion in mineral oil, 5.44 g, 142 mmol). The mixture was stirred at room temperature for 15 min and then 2-bromoethyl methyl ether (18.3 g, 131 mmol) was added. The reaction mixture was warmed to 85° C. and stirred overnight. After cooling to room temperature, the mixture was diluted with ethyl acetate and washed with water. The organic extract was dried (MgSO4), filtered, and concentrated. The residue was purified by flash chromatography on SiO2 using a gradient of 0% to 100% ethyl acetate:hexane to provide 10.3 g (42%) of the title compound as the more polar regioisomer: 1H NMR (300 MHz, CDCl3) δ 2.28 (s, 3H) 3.35 (s, 3H) 3.65-3.71 (m, 2H) 4.28-4.36 (m, 2H) 7.00 (s, 1H); MS (ESI+) m/z 235 (M+H)+.
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