Selectfluor → Methyl 6-amino-5-bromo-3-fluoropicolinate
Reaktionsgleichung
[NH2:1][C:2]1[N:7]=[C:6]([C:8]([O:10][CH3:11])=[O:9])[CH:5]=[CH:4][C:3]=1[Br:12].[F:13][B-](F)(F)F.F[B-](F)(F)F.ClC[N+]12CC[N+](F)(CC1)CC2>C(#N)C>[NH2:1][C:2]1[N:7]=[C:6]([C:8]([O:10][CH3:11])=[O:9])[C:5]([F:13])=[CH:4][C:3]=1[Br:12]Komponenten
4
Edukt 2
Produkt 1
Reagenzien, Katalysatoren, Lösungsmittel 1
Versuchsvorschrift
A mixture of methyl 6-amino-5-bromopyridine-2-carboxylate (19.8 g) (T. R. Kelly and F. Lang, J. Org. Chem. 61, 1996, 4623-4633) and 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (34.3 g) in acetonitrile (340 ml) under argon was heated to 40° C. for 1 hour, 60° C. for 1 hour and then 80° C. overnight. After partitioning between EtOAc and water (500 ml each) the aqueous fraction was re-extracted with EtOAc (300 ml) and the combined organic solution dried with MgSO4 and evaporated. Chromatography (20% then 30% EtOAc in hexane) separated various byproducts from the required ester (2.09 g).