反应详情

A mixture of 2,4-dibromophenol (5.0 g) and 2-methoxypropene (4 ml) was stirred for one hour at room temperature, to which was added diethyl ether (50 ml). The mixture was cooled to -78° C. under argon atmosphere, to which was added dropwise a 1.6M n-butyl lithium hexane solution (14 ml), followed by stirring for one hour at the same temperature. To the reaction mixture was then added dropwise 2-cyanopyridine (2.1 ml). The cooling bath was removed, and the reaction mixture was stirred for 3 hours while warming up to room temperature. To the reaction mixture was added ethanol (10 ml), followed by stirring for several minutes. Then, the solvent was distilled off under reduced pressure. To the residue were added triethylamine (20 ml), O-t-butylhydroxylamine hydrochloride (2.5 g) and ethanol (50 ml). The mixture was heated for 5 hours under reflux, then the solvent was distilled off. To the residue were added chloroform and water for extraction. The organic layer was dried (anhydrous magnesium sulfate), then the solvent was distilled off under reduced pressure. The residue was purified by subjecting to a silica gel column chromatography, eluting with ethyl acetate/hexane to give (Z)-2-(5-bromo-2-hydroxybenzoyl)pyridine O-t-butyloxime (4.24 g) (Compound 75).

1. temperatureThe mixture was cooled to -78° C. under argon atmosphere, to which
2. stirringby stirring for one hour at the same temperature
3. customThe cooling bath was removed
4. stirringthe reaction mixture was stirred for 3 hours
5. temperaturewhile warming up to room temperature
6. additionTo the reaction mixture was added ethanol (10 ml)
7. stirringby stirring for several minutes
8. distillationThen, the solvent was distilled off under reduced pressure
9. additionTo the residue were added triethylamine (20 ml), O-t-butylhydroxylamine hydrochloride (2.5 g) and ethanol (50 ml)
10. temperatureThe mixture was heated for 5 hours
11. temperatureunder reflux
12. distillationthe solvent was distilled off
13. additionTo the residue were added chloroform and water
14. extractionfor extraction
15. dry with materialThe organic layer was dried (anhydrous magnesium sulfate)
16. distillationthe solvent was distilled off under reduced pressure
17. customThe residue was purified
18. washeluting with ethyl acetate/hexane