Reaktion #690449

Reaktionsgleichung

7-hydroxy-4′-methoxyisoflavanone

acetic anhydride

pyridine

→

7-acetoxy-4′-methoxyisoflavone

Ausbeute 91.0%

Lösungsmittel

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas heated on an oil bath at 105-110 C
2. 2
   Extraktionextracted with dichloromethane (3×50 ml)
3. 3
   WaschenThe dichloromethane layer was washed with water
4. 4
   Trocknendried over anhydrous sodium sulfate
5. 5
   Sonstigeevaporated
6. 6
   SonstigeThe white residue was crystallised from methanol

Vorschrift

A mixture of 7-hydroxy-4′-methoxyisoflavanone (2.0 g, 7.5 mmol), acetic anhydride (10 ml) and pyridine (2 ml) was heated on an oil bath at 105-110 C. for 1 hour. After cooling the mixture to room temperature, it was poured into water (100 ml), stirred for 2 hours and then extracted with dichloromethane (3×50 ml). The dichloromethane layer was washed with water, dried over anhydrous sodium sulfate and evaporated. The white residue was crystallised from methanol to yield 7-acetoxy-4′-methoxyisoflavone as colourless prisms (2.1 g, 91%). 1H NMR (CDCl3): δ 2.36 (s, 3H, OCOCH3), 3.84 (s, 3H, OCH3), 6.98 (d, 2H, J 8.7 Hz, ArH), 7.16 (dd, 1H, J 1.9 Hz 8.6 Hz, H6), 7.30 (d, 1H, J 1.9 Hz H8), 7.50 (d, 2H, J 8.7 Hz, ArH), 8.00 (s, 1H, H2), 8.32 (d, 1H, J 8.6 Hz, H5).

Quelle