Poronik Y. Dyes based on xanthylium cores with electron-donor substituents

Synthetic methods have been developed which afford xanthylium salts with four types of electron-donor substituents and a number of xanthylocyanines have been derived from them. The influence of substitients electron-donor ability has been investigated. A new preparatively convenient access to 2-hydroxy-4-diethylamino-acetophenone has been elaborated. New coumarinocoumarine derivatives have been obtained. A number of bis-dyes have been synthesized based on the pyronine nucleus. The electronic spectra of these compounds exhibit absorption bands shifted and their intensities changed as compared to parent dyes. A novel synthetic route to rhodamine dyes has been found. Annelation of the terminal nitrogen atoms causes a bathochromic shift of the absorption maximum and an increase in the fluorescence quantum yield.