[Br:1][C:2]1[S:6][C:5]([C:7]([S:10](CCC(OC)=O)(=[O:12])=[O:11])([CH3:9])[CH3:8])=[N:4][CH:3]=1.C[O-].[Na+].CC([O-])=O.[Na+].[NH2:27]OS(O)(=O)=O>C1COCC1.O>[Br:1][C:2]1[S:6][C:5]([C:7]([S:10]([NH2:27])(=[O:12])=[O:11])([CH3:9])[CH3:8])=[N:4][CH:3]=1The product of Step 4 (2.50 g, 7.02 mmol) was taken up in THF (80 mL) at room temperature, and NaOMe (25% in MeOH, 1.52 g, 7.02 mmol) was added. After 30 min at room temperature, the suspension was evaporated to dryness, providing a white solid. The solid was taken up in water (50 mL), and a solution of NaOAc (3.17 g, 38.6 mmol) and hydroxylamine-O-sulfonic acid (3.97 g, 35.1 mmol) in water (25 mL) was added while cooling the reaction (0° C.). The reaction was vigorously stirred at room temperature overnight (a white solid precipitated after 15-30 min). The reaction was extracted with ethyl acetate (2×). The combined organic layers were washed with brine, dried (MgSO4), filtered and evaporated. The resulting white residue was triturated with CH2Cl2 and filtered to provide 2-(5-bromo-1,3-thiazol-2-yl)propane-2-sulfonamide (1.58 g, 79%) as a white powder. ESI: [M+H]+ m/z 284.9/286.9.
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