The synthesis and spectral characteristics of novel 6-(2-substituted-1,3,4-oxadiazol-5-yl)-2-phenylthieno[2,3-d]pyrimidine fluorescent compounds derived from 5-cyano-1,6-dihydro-4-methyl-2-phenyl-6-thioxopyrimidine

A series of novel 6-(2-substituted-1,3,4-oxadiazol-5-yl)-2-phenylthieno[2,3-d]-pyrimidine fluorescent compounds were obtained by the condensation of 6-(2-methylthio-1,3,4-oxadiazol-5-yl)-2-phenylthieno[2,3-d]pyrimidine with appropriate secondary amines. The structures were characterized by IR, 1H NMR, mass, elemental analysis and UV–vis spectroscopy and the fluorescence characteristics were investigated in ethyl acetate and acetone by UV–vis absorption and emission spectra. The absorption spectra and fluorescence characteristics were correlated with substituents of the 6-(2-substituted-1,3,4-oxadiazol-5-yl)-2-phenylthieno[2,3-d]pyrimidine compounds and solvent polarity. The novel compounds also displayed intense blue to yellow-green fluorescence in ethyl acetate and acetone solutions.