No abstract

A new type of intramolecular cyclization of 1,5 bis[2 (E 3 oxo 3 phenylprop 1 enyl) phenoxy] 3 oxapentane with 3 aminotriazole promoted by potassium ions was discovered. A cascade mechanism for the formation of crownophane with 4,7 dihydro[1,2,4]triazolo[1,5 a] pyrimidine fragment was suggested. Effects of oligooxyethylene fragment of the chalcone podand and acid base catalysis on the selectivity of the cyclocondensation processes and degree of oxidation of triazolopyrimidine fragments were studied. The product structures were confirmed by IR, 1 H and 13 C NMR spectroscopy and X ray diffraction study.

As eries of V-shaped luminophores containing electron-withdrawing quinoxalinec ore and arylthienyl donor fragments at positions 2a nd 3h as been successfully synthesized. Their photophysical properties in two solvents as well as halochromism have been studied, and the ability of 4-diethylaminophenyld erivative to function as colorimetric and luminescent pH sensorh as been demonstrated with significant color changes and luminescence switching upon the introductionofa cid.