N-bromobutanimide → tert-butyl 3-(4-bromo-1-methyl-1H-pyrazol-5-yl)pyrrolidine-1-carboxylate
Reaktionsgleichung
[CH3:1][N:2]1[C:6]([CH:7]2[CH2:11][CH2:10][N:9]([C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])[CH2:8]2)=[CH:5][CH:4]=[N:3]1.C1C(=O)N([Br:26])C(=O)C1>C1COCC1>[Br:26][C:5]1[CH:4]=[N:3][N:2]([CH3:1])[C:6]=1[CH:7]1[CH2:11][CH2:10][N:9]([C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])[CH2:8]1Komponenten
4
Versuchsvorschrift
A mixture of tert-butyl 3-(1-methyl-1H-pyrazol-5-yl)-pyrrolidine-1-carboxylate (2.3 g, 7.0 mmol) and NBS (1.48 g, 8.39 mmol) in THF (50 mL) was stirred at room temperature for 1 h. Solvent was removed to afford the crude product, which was purified by reverse phase Combiflash eluting with a 0-70% gradient of CH3CN in 0.3% NH4HCO3 to give tert-butyl 3-(4-bromo-1-methyl-1H-pyrazol-5-yl)pyrrolidine-1-carboxylate (2.28 g, 75% yield) as white solid. LCMS (ESI) m/z: 332.1 [M+H+]. 1H-NMR (500 MHz, CDCl3) δ 7.38 (s, 1H), 3.88 (s, 3H), 3.75-3.61 (m, 3H), 3.52 (s, 1H), 3.38 (s, 1H), 2.48 (s, 1H), 2.15 (s, 1H), 1.48 (s, 9H).