Oxidative cyclization of N-(2-oxo-4-phenyl-1,2-dihydropyridin-3-yl)thioureas to 7-phenyloxazolo[5,4-b]pyridin-2-amines
摘要
The reaction of N-(2-oxo-4-phenyl-1,2-dihydropyridin-3-yl)thioureas with hydrogen peroxide in aqueous ethanol proceeded via the oxidation of the sulfur atom and its subsequent replacement with the oxygen atom of pyridin-2-one to give oxazolo[5,4-b]pyridin-2-amines. 7-Phenyloxazolo[5,4-b]pyridin-2-amines were found to be effective luminophores emitting in the violet spectral range with quantum yields up to 0.59, whereas the corresponding thioureas have no luminescent properties.