Polymethine dyes — 4-methylbenzofuro- and 4-methylbenzoselenopheno[2,3-b]pyridine derivatives

Polymethine dyes of various types were obtained from quaternary salts of 4-methylbenzofuro- and 4-methylbenzoselenopheno2,3-b]pyridines. It is shown that replacement of the vinylene group in the benzene ring of the benzoh]-4-quinoline residue by an oxygen or selenium atom gives rise to a larger hypsochromic shift of the absorption maxima of the corresponding cyanine dyes than replacement by a sulfur atom. Dyes with benzofuro2,3-b]-4-pyridine residues absorb in the shorter-wave region of the spectrum than benzothieno- and benzoselenopheno2,3-b]pyridine derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1357–1360, October, 1976.