[S:1]1[CH:5]=[CH:4][N:3]=[C:2]1[C:6]1([OH:16])[CH2:15][CH2:14][C:9]2([O:13][CH2:12][CH2:11][O:10]2)[CH2:8][CH2:7]1.C1C(=O)N([Br:24])C(=O)C1.O.[O-]S([O-])=O.[Na+].[Na+]>CN(C=O)C>[Br:24][C:5]1[S:1][C:2]([C:6]2([OH:16])[CH2:7][CH2:8][C:9]3([O:13][CH2:12][CH2:11][O:10]3)[CH2:14][CH2:15]2)=[N:3][CH:4]=1
The product of Step 1 (60.5 g, 251 mmol) was diluted with DMF (5 mL). To this solution, NBS (49.1 g, 276 mmol) was added. The reaction was heated to 50° C. for 2 h. The reaction was cooled to 45° C. and H2O (600 mL) containing Na2SO3 (15.8 g, 125 mmol) was added drop wise. The reaction was stirred at room temperature for 1 h then filtered and washed with H2O (2×, 300 mL). The filtrate was dried under nitrogen to afford 8-(5-bromo-1,3-thiazol-2-yl)-1,4-dioxaspiro[4.5]decan-8-ol (68.15 g, 213 mmol, 85% yield).
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