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 one liter three-necked flask which had been flushed with nitrogen. The flask is heated gradually in an oil-bath to 140° C. After 20 hours, the flask is cooled to 100° C. and poured into 8 l of water. The precipitate is dissolved by adding potassium hydroxide (302 g) in 2 l of water. The aqueous solution is extracted with ether, and the ether extracts are washed 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.