N-bromobutanimide → HCID 49765956, compound
Reaction equation
[CH3:1][O:2][CH:3]([O:24][CH3:25])[CH2:4][N:5]1[CH:10]=[CH:9][C:8](=[O:11])[C:7]([O:12][CH2:13][C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=2)=[C:6]1[C:20]([O:22][CH3:23])=[O:21].C1C(=O)N([Br:33])C(=O)C1>ClCCl>[CH3:25][O:24][CH:3]([O:2][CH3:1])[CH2:4][N:5]1[CH:10]=[C:9]([Br:33])[C:8](=[O:11])[C:7]([O:12][CH2:13][C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=2)=[C:6]1[C:20]([O:22][CH3:23])=[O:21]Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
A 2 L flask equipped with a mechanic stirrer were charged with methyl 1-[2,2-bis(methyloxy)ethyl]-4-oxo-3-[(phenylmethyl)oxy]-1,4-dihydro-2-pyridinecarboxylate 23 as obtained above and 500 mL of dichloromethane. To this flask was added NBS (30 g, 0.17 mole) portion-wise. The reaction was stirred at room temperature until its completion (monitored by TLC, ˜6 hours). The mixture was then diluted with dichloromethane and washed with NaHCO3 (ss). The organic phase was dried over Na2SO4 before evaporation of the solvents. The crude product was purified by column chromatography (silica gel, EtOH/DCM: 0-40%) to afford methyl 1-[2,2-bis(methyloxy)ethyl]-5-bromo-4-oxo-3-[(phenylmethyl)oxy]-1,4-dihydro-2-pyridinecarboxylate 24 as a light brown solid (50 g, 60% over three steps). 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 7.7 (s, 1H), 7.4 (m, 2H), 7.3 (d, J=7.9 Hz, 3H), 5.3 (s, 2H), 4.4 (s, 1H), 3.8 (d, J=4.8 Hz, 2H), 3.8 (s, 3H), 3.4 (s, 6H). LC-MS (M+H+): calcd 426, obsd 426.