[CH3:1][C:2]1[N:3]=[C:4]([NH2:7])[S:5][CH:6]=1.[Br:8][CH:9]([CH3:17])[C:10](=O)[CH2:11][C:12](OC)=[O:13].[OH-].[Na+]>C(Cl)Cl>[Br:8][CH:9]([C:10]1[N:7]=[C:4]2[S:5][CH:6]=[C:2]([CH3:1])[N:3]2[C:12](=[O:13])[CH:11]=1)[CH3:17]To a manually stirred polyphosphoric acid (80 g, 800 mmol) in a 1000 mL beaker was added 4-methyl-1,3-thiazol-2-amine (Aldrich, 16 g, 140 mmol), followed by methyl 4-bromo-3-oxopentanoate (34.9 g, 167 mmol). The mixture was heated with stirring at 110° C. for 5 h. After cooling, the dark slurry was transferred into 300 g of ice. The pH of the mixture was adjust to 6-7 with 10% sodium hydroxide. The aqueous layer was discarded and the dark oil layer was diluted with methylene chloride and washed with 1 N NaOH, brine, dried over magnesium sulfate, and evaporated to dryness to yield the desired product (16.2 g, 42.6%). LCMS calculated for C9H10BrN2OS (M+H)+: m/z=273.0. Found: 273.1.
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