7-Hydroxy-4-(3-pyridyl)coumarin → 7-Bromo-4-(pyridin-3-yl)-2H-1-benzopyran-2-one
Reaktionsgleichung
O[C:2]1[CH:11]=[C:10]2[C:5]([C:6]([C:13]3[CH:14]=[N:15][CH:16]=[CH:17][CH:18]=3)=[CH:7][C:8](=[O:12])[O:9]2)=[CH:4][CH:3]=1.[Br-:19].[Br-].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>C(O)C>[Br:19][C:2]1[CH:11]=[C:10]2[C:5]([C:6]([C:13]3[CH:14]=[N:15][CH:16]=[CH:17][CH:18]=3)=[CH:7][C:8](=[O:12])[O:9]2)=[CH:4][CH:3]=1Komponenten
4
Edukt 2
Produkt 1
Reagenzien, Katalysatoren, Lösungsmittel 1
Versuchsvorschrift
Commercially available 7-hydroxy-4-(3-pyridyl)coumarin (1.48 g, 6.19 mmol) and triphenylphosphine dibromide (5.22 g, 12.4 mmol) are heated in a sand bath at 320-350° C. for 1.5 h. The cooled solid is taken up with ethanol (200 ml) and silica gel (100 g) and evaporated to dryness. Column chromatography (toluene/acetone; 80:20) affords 7-bromo-4-pyridin-3-yl-2H-chromen-2-one.