反应详情

温度

0 °C

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).

1. temperatureunder reflux for 4 hours
2. distillationThe methanol is distilled off under reduced pressure
3. extractionextracted with 4 times 100 ml of ethyl acetate
4. dry with materialThe organic phase is dried over sodium sulphate
5. distillationthe solvent is distilled off under reduced pressure