Propionic anhydride → CID 367964
Reaktionsgleichung
[F:1][C:2]1[CH:9]=[CH:8][C:5]([CH:6]=O)=[CH:4][CH:3]=1.[C:10]([O:14]C(=O)CC)(=[O:13])[CH2:11][CH3:12].C([O-])(=O)CC.[Na+]>>[F:1][C:2]1[CH:9]=[CH:8][C:5]([CH:6]=[C:11]([CH3:12])[C:10]([OH:14])=[O:13])=[CH:4][CH:3]=1Komponenten
4
Reaktionsbedingungen
- Temperatur
- 140 °C
Versuchsvorschrift
p-Fluorobenzaldehyde (200 g, 1.61 mol), propionic anhydride (3.5 g, 2.42 mol) and sodium propionate (155 g, 1.61 mol) are mixed in a nitrogen-flushed 1 l three-necked flask. The flask is heated gradually in an oil-bath to 140° C. After 20 hours, the contents are cooled to 100° C., and are poured into 8 l of water. The precipitate is dissolved by adding potassium hydroxide (302 g) in water (2 l). The aqueous solution is washed with ether, and the ether layers are re-extracted with potassium hydroxide solution. The combined aqueous layers are filtered, are acidified with concentrated HCl, and are filtered. The collected solid, p-fluoro-α-methylcinnamic acid, is washed with water, and is dried and used as obtained.