Cl[CH2:2][C:3]1[N:4]=[C:5]([CH:8]2[CH2:10][CH2:9]2)[S:6][CH:7]=1.CS(C)=[O:13]>CCOC(C)=O.O=[Mn]=O>[CH:8]1([C:5]2[S:6][CH:7]=[C:3]([CH:2]=[O:13])[N:4]=2)[CH2:10][CH2:9]1To a solution of 4-(chloromethyl)-2-cyclopropylthiazole (3.0 g, 17.2 mmol) in DMSO (10 mL) was charged MnO2 (1.5 g, 17.2 mmol). The mixture was heated to 100° C. overnight, cooled to room temperature and diluted with EtOAc (30 mL). The mixture was filtered through Celite and washed with EtOAc (3×30 mL). The combined organic layer was washed with brine (3×40 mL) and concentrated. The residue was purified by silica gel chromatography using 2 to 5% EtOAc in hexane to afford the title compound (1.0 g, 38%) as a light brown oil, which solidified upon standing in a refrigerator overnight. 1H NMR (400 MHz, CDCl3) δ 9.91 (s, 1H), 7.93 (s, 1H), 2.36 (m, 1H), 1.20 (m, 2H), 1.16 (m, 2H). MS (ES) m/z 154.1 (M+H+).
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