Azobisisobutyronitrile → 2-Bromo-5-(chloromethyl)-3-fluoropyridine
Reaktionsgleichung
[Br:1][C:2]1[N:7]=[CH:6][C:5]([CH3:8])=[CH:4][C:3]=1[F:9].BrN1C(=O)CCC1=O.N(C(C)(C)C#N)=NC(C)(C)C#N.[Cl:30]C1C=CC=CC=1>>[Br:1][C:2]1[N:7]=[CH:6][C:5]([CH2:8][Cl:30])=[CH:4][C:3]=1[F:9]Komponenten
5
Versuchsvorschrift
10.00 g (52.63 mmol) of 6-bromo-5-fluoro-3-methylpyridin (cf. F. L. Setliff, Organic Preparations and Procedures International 1971, 3, 217-222), 12.18 g (68.42 mmol) of N-bromosuccinimide and 0.86 g (5.26 mmol) of 2,2′-azobis(2-methylpropanenitrile) in 1 of chlorobenzene are boiled under reflux for 6 hours. The reaction mixture is washed with saturated aqueous sodium sulphite solution and sodium bicarbonate solution and then dried over sodium sulphate and concentrated under reduced pressure. Column chromatography of the residue on silica gel (silica gel 60-Merck, particle size: 0.04 to 0.063 mm) using the mobile phase mixture ethyl acetate:cyclohexane (1:20) gives 6.0 g (42% of theory) of 6-bromo-3-chloromethyl-5-fluoropyridine.