Pyrylocyanines. 13. Symmetrical pyrylocyanines based on 2,3-polymethylene-4,6-diphenylpyrylium salts

Article abstract of DOI:10.1007/BF00505591

Symmetrical 4,6,4′,6′-tetraphenyl-substituted pyrylo-2-, thiopyrylo-2-, and pyrylo-2-cyanines in which both α positions of the polymethine chain are bonded to the β positions of the heterocyclic residues by ethylene and trimethylene groups were synthesize