Reaktion #56517

Reaktionsgleichung

9-hydroxy-1-oxo-1H-naphtho[2,1-b]pyran-2-carboxaldehyde acetate

malonic acid

malonic acid

→

crystals

Ausbeute 25.5%

[9-(acetyloxy)-1-oxo-1H-naphtho[2,1-b]pyran-2-yl]-2-propenoic acid

Ausbeute 25.5%

Lösungsmittel

pyridine

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturis refluxed for 45 minutes
2. 2
   Temperaturthe reaction refluxed for 30 minutes
3. 3
   SonstigeThe solvent is removed under reduced pressure
4. 4
   Sonstigeto give a sludge from which product
5. 5
   Sonstigecrystallizes on the addition of acetone
6. 6
   FiltrationAfter filtering
7. 7
   Sonstigethe product, recrystallization from DMF

Vorschrift

A mixture of 9-hydroxy-1-oxo-1H-naphtho[2,1-b]pyran-2-carboxaldehyde acetate (10.0 g, 0.0354 m) and malonic acid (4.0 g, 0.0354 m) in pyridine (100 ml) is refluxed for 45 minutes. Additional malonic acid (1.0 g, 0.00885 m, 0.25 eq.) is added and the reaction refluxed for 30 minutes. The solvent is removed under reduced pressure to give a sludge from which product crystallizes on the addition of acetone. After filtering the product, recrystallization from DMF gives cocoa crystals (2.75 g, 24%), m.p. dec>290° C.

Quelle