Boron tribromide → 4,6-Dihydroxy-2H-1-benzopyran-2-one
Reaktionsgleichung
[OH:1][C:2]1[C:11]2[C:6](=[CH:7][CH:8]=[C:9]([O:12]C)[CH:10]=2)[O:5][C:4](=[O:14])[CH:3]=1.B(Br)(Br)Br>C(Cl)Cl>[OH:1][C:2]1[C:11]2[C:6](=[CH:7][CH:8]=[C:9]([OH:12])[CH:10]=2)[O:5][C:4](=[O:14])[CH:3]=1Komponenten
4
Edukt 2
Produkt 1
Reagenzien, Katalysatoren, Lösungsmittel 1
Reaktionsbedingungen
- Temperatur
- -78 °C
Versuchsvorschrift
4-Hydroxy-6-methoxy-chromen-2-one (500 mg, 2.588 mmol) was suspended in CH2Cl2 (10 mL) and cooled to −78° C. under nitrogen. BBr3 (1 M solution in CH2Cl2, 13 mL, 13 mmol) was added to this suspension dropwise. Following completion of the addition, the resulting suspension was stirred at 25° C. for 1 h before being quenched by the slow addition of H2O. The product was extracted with EtOAc and the combined organic layers dried over Na2SO4 and concentrated to give 350 mg (75%) of the title compound as a tan solid. MS (ESI(+)Q1MS) m/z 179 (M+H)+; 1H NMR (300 MHz, DMSO) δ ppm 9.71 (bs, 1H), 7.01-7.23 (m, 3H), 5.57 (s, 1H).