Absorption and Fluorescence Spectra of 4, 7-Di (alkoxy-substituted) pheny1-1, 2, 5-thiadiazolo (3, 4-c) pyridine

A series of 4, 7-Di (alkoxy-substituted) phenyl-1,2,5-thiadiazolo[3, 4-c]pyridines were prepared and their absorption and fluorescence spectre were obatined. These compounds showed a large stokes shift of 115-135 nm arid 6-aryl derivatives and 6-alkoxycarbonyl opes are strongly fluorescent in a solid state. and 1, 2, 5-oxadiazolo[3, 4-c]pyridine are strongly fluorescent in a solid state and, as a dyestuff, the for-mer is superior to the latter in the durablity.`) As a part of our studies on fluorescent heterocycles, we now report on the fluorescence of alkoxy-substituted 4, 6, 7-tri- and 4, 7-diaryl-1, 2, 5-thiadiazolo[3, 4-c]pyridines.