N-bromobutanimide → tert-Butyl 2-(4-bromo-5-oxo-2,5-dihydrofuran-3-yl)-1-oxo-2,8-diazaspiro[4.5]decane-8-carboxylate
Reaction equation
[O:1]=[C:2]1[C:6]2([CH2:11][CH2:10][N:9]([C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])[CH2:8][CH2:7]2)[CH2:5][CH2:4][N:3]1[C:19]1[CH2:20][O:21][C:22](=[O:24])[CH:23]=1.C1C(=O)N([Br:32])C(=O)C1>C(Cl)Cl>[Br:32][C:23]1[C:22](=[O:24])[O:21][CH2:20][C:19]=1[N:3]1[CH2:4][CH2:5][C:6]2([CH2:11][CH2:10][N:9]([C:12]([O:14][C:15]([CH3:17])([CH3:18])[CH3:16])=[O:13])[CH2:8][CH2:7]2)[C:2]1=[O:1]Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
tert-Butyl 1-oxo-2-(5-oxo-2,5-dihydrofuran-3-yl)-2,8-diazaspiro[4.5]decane-8-carboxylate (I-16, Step A) (784 mg, 2.33 mmol) was dissolved in DCM (20 mL) and was treated with NBS (498 mg, 2.80 mmol) at 25° C. for 12 hours. The reaction mixture was diluted with DCM (20 mL), washed with water (20 mL) and brine (20 mL), dried over anhydrous sodium sulfate and filtered. The filtrates were concentrated and the crude product was purified by column chromatography (ISCO 40 g silica gel column), eluting with 50-100% ethyl acetate/hexane gradient to give the title compound.