Pyrylocyanines. 16. Tetraphenyl-substituted (2-pyrylo) (4-pyrylo) cyanines

Unsymmetrical tetraphenyl-substituted (2-pyrylo) (4-pyrylo) monomethylidyne-, carbo-, and dicarbocyanines and their thiopyrylium and pyridinium analogs were synthesized. The absorption spectra of these dyes were studied. The spectral characteristics of their long-wave absorption bands have values that are intermediate between the analogous characteristics of the corresponding symmetrical isomers of the and series.See 1] for communication 15.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1178–1183, September, 1982.