O[CH2:2][C:3]1[CH:8]=[CH:7][C:6]([CH2:9][CH2:10][N:11]2[CH:16]=[CH:15][C:14]([CH2:17][CH2:18][C:19]3[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=3)=[CH:13][C:12]2=[O:25])=[CH:5][CH:4]=1.P(Br)(Br)[Br:27].C([O-])(O)=O.[Na+]>C(Cl)Cl>[Br:27][CH2:2][C:3]1[CH:8]=[CH:7][C:6]([CH2:9][CH2:10][N:11]2[CH:16]=[CH:15][C:14]([CH2:17][CH2:18][C:19]3[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=3)=[CH:13][C:12]2=[O:25])=[CH:5][CH:4]=1To 150 mg (0.45 mmol) 1-[2-(4-hydroxymethyl-phenyl)-ethyl]-4-phenethyl-1H-pyridin-2-one (example 18.1a) in 2.0 mL of DCM is added at 0° C. 21 μL (0.23 mmol) phosphorus tribromide. The mixture is stirred 2 h at RT and is then added to aqueous 5% NaHCO3-solution. The layers are separated, the aqueous phase is extracted with DCM. The combined organic phase is washed with water, dried over MgSO4, filtered and the solvent is evaporated to afford the product.
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