Pyridine-2-carbonitrile → 4-bromo-2-[(Z)-N-[(2-methylpropan-2-yl)oxy]-C-pyridin-2-ylcarbonimidoyl]phenol

Beteiligte Stoffe

Reaktionsschritte

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).

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