Methanol → 2-bromo-1-(2-hydroxy-phenyl)-ethanone O-methyl-oxime
Reaktionsgleichung
[Br:1][CH:2](O)[C:3]([C:5]1[CH:10]=[CH:9][CH:8]=[CH:7][CH:6]=1)=O.Cl.[CH3:13][O:14][NH2:15].C[OH:17]>>[CH3:13][O:14][N:15]=[C:3]([C:5]1[CH:10]=[CH:9][CH:8]=[CH:7][C:6]=1[OH:17])[CH2:2][Br:1]Komponenten
4
Reaktionsbedingungen
- Temperatur
- 0 °C
Versuchsvorschrift
107.5 g (0.5 mol) of ω-bromo-2-hydroxy-acetophenone in 500 ml of methanol together with 41.75 g (0.5 mol) of O-methylhydroxylamine hydrochloride are heated under reflux for 4 hours. The methanol is distilled off under reduced pressure and the residue is admixed with 500 ml of water and extracted with 4 times 100 ml of ethyl acetate. The organic phase is dried over sodium sulphate and the solvent is distilled off under reduced pressure. At 0° C. , the residue is stirred with petroleum ether, affording 74 g (52% of theory) of crystalline 2-bromo-1-(2-hydroxy-phenyl)-ethanone O-methyl-oxime as a mixture of two stereoisomers (53% of isomer B and 33% of isomer A).