Pyrylocyanines

From 4-methyl-2,6-diphenylthiopyrylium and 4-methyl-2,6-diphenylselenopyrylium salts thio- and selenopyrylocyanines with symmetrical structures have been synthesized. In the series of dyes synthesized, greater values of the vinylidene shifts of the absorption maxima are observed than in the series of their thio- and selenoflavylium analogs. The mono-, tri-, and penta-methinecyanines obtained are more highly colored than the analogous thio- and selenoflavylo-cyanines and, conversely, the 2,6-diphenylselenopyryloheptamethinecyanines are colored less deeply than the selenoflavylotricarbocyanines. The structure of the product of the oxidation of 4-methyl-2,6-diphenylpyrylium perchlorate has been established.For Communication III, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 49–52, January, 1974.     

Pyrylocyanines

Tetraalkyl-substituted 4-pyrolocyanines were synthesized and converted to pyridocyanines by reaction with methylamine. The exchange reaction proceeds particularly readily in the series of tetramethyl-substituted compounds, in which the oxygen atoms in one or both pyrylium residues can be replaced, depending on the conditions. It was established that, in contrast to the tetraphenyl-substituted compounds, among the tetramethyl-substituted compounds the symmetrical dyes (pyridinium derivatives) are more deeply colored than their oxygen-containing analogs. The reasons for this difference in the absorption spectra are analyzed thoroughly by the quantum-chemical method.See [1] for communication VII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 739–743, June, 1978.     

Pyrylocyanines

Depending on the reaction conditions, in the reaction of symmetrical 2,6-diphenyl-4-pyrylomonomethine-, carbo-, and dicarbocyanines with methylamine the oxygen atoms in one or both pyrylium residues are replaced to give both unsymmetrical pyrylopyrido- and symmetrical pyridocyanines. The deviations for the synthesized dyes increase as the lengths of the polymethine chromophore increases.See [1] for communication V.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 612–616, May, 1975.     

Pyrylocyanines

The reaction of selenoflavone with methylmagnesium iodide and with methyl o-nitrobenzenesulfonate was used to synthesize 4-methyl- and 4-methoxyselenoflavylium salts, from which a number of polymethine dyes of symmetrical structure were obtained. The selenoflavylocyanines have a considerably deeper color than other polymethine dyes with the same chromophore length.See [1] for communication I.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 924–926, July, 1971.     

Pyrylocyanines. 10. Isobenzothiopyrylocyanines

Polymethine dyes with symmetrical and unsymmetrical structures and 3-phenyl-2-benzothiopyrylium derivatives were synthesized. The color of these dyes is discussed. See [1] for communication No. 9. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 777–782, June, 1980.     

Pyrylocyanines. 9. Isobenzopyrylocyanines

Polymethine dyes with symmetrical and unsymmetrical structures, viz., 3-phenyl-2-benzopyrylium derivatives, were synthesized. Their colors are discussed. See [1] for communication 8. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 193–198, February, 1980.     

Pyrylocyanines. 15. Benzopyrylo-2-cyanines

Symmetrical 4,4-diphenyl-substituted benzopyrylo-2-monomethylidyne, carbo-, and dicarbocyanines and their thio analogs, as well as unsymmetrical carbocyanines that contain, in addition to 4-phenylbenzopyrylium or 4-phenylbenzothiopyrylium rings, 3-ethylbenzothiazolium or 1,3,3-trimethyl-3H-indolium residues, were synthesized. The indicated dyes were more highly colored than their isomers that contain flavylium or thioflavylium residues. On the basis of the deviations calculated from the centers of the absorption bands it was concluded that the benzopyran residues in the dyes of the series have greater electron donor character than those in the dyes of the series.See [1] for communication 14.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1173–1177, September, 1982.     

Pyrylocyanines. 29. tert-Butyl-substituted benzopyrylocyanines

2-tert-Butyl-4-methyl- and 2-methyl-4-tert-butylbenzopyrylium salts, as well as the sulfitr analog of the latter, were synthesized. Polymethine dyes with symmetrical and unsymmetrical structures were obtained from these salts. The factors that affect the color are analyzed.See [1] for Communication 28.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 339–344, March, 1992.     

Pyrylocyanines. 12. Unsymmetrical pyrylo-2-cyanines

Unsymmetrical 4,6-diphenylpyrylo-2- and 2,6-diphenylpyrylo-4-carbo- and -dicarbocyanines, as well as the analogous pyridocyanines containing 3-ethylbenzothiazolium and 1,3,3-trimethyl-3H-indolium residues, were synthesized. The pyrylo-2-cyanines are more deeply colored than the corresponding 4 isomers, and their absorption bands are distinguished by lower intensities and greater widths. On the basis of data on the increase in the width of the absorption bands of unsymmetrical dyes as the length of their polymethine chain increases it is concluded that the -pyran system has greater electron-donor character than the -pyran system. The regularities observed in the pyridocyanine series are just the opposite of these.See [1] for Communication 11.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 903–908, July, 1980.     

Pyrylocyanines. 11. Symmetrical tetraphenyl-substituted pyrylo-2-cyanines

Symmetrical polymethine dyes (monomethylidyne, carbo-, and dicarbocyanines), viz., 4,6-diphenylpyrylium, -thiopyrylium, and -pyridinium derivatives, were synthesized. It follows from a comparison of the absorption spectra of pyrylo-2-cyanines and their heteroanalogs with the spectra of the corresponding 4 isomers that these dyes differ from one another with respect to the positions, intensities, and forms of the bands. The pyrylocarbo- and -dicarbocyanines and their sulfur analogs are more deeply colored than their isomers, while the reverse regularity is observed in the pyridocyanine series. The long-wave bands in the spectra of all of the isomers are accompanied by more intensive transitions to the vibrational sublevels than in the case of the isomers.See [1] for Communication 10.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 898–902, July, 1980.     

Pyrylocyanines. 20. Symmetrical methoxy-substituted tetraphenyl-pyrylocyanines and their heteroanalogs

Symmetrical tetraphenyl-substituted -pyrylo-, -thiopyrylo-, and -pyridotrimethylcyanines, containing electron donor methoxy groups in two or four phenyl rings, were synthesized. Using the methods of quantum chemistry, the characteristics of the long-wave absorption bands of the dyes obtained are discussed. The independence of the theoretical conclusions from the selection of the quantum chemical parameters was demonstrated. The hypothesis of greater participation of the carbon-carbon bonds of the oxygen- and especially the sulfur-containing heteroresidues in comparison with the nitrogen-containing residues in the general system of conjugation is confirmed.For communication 19, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1486–1491, November, 1984.     

Pyrylocyanines. 21. Unsymmetrical α-pyrylo- and α-pyridocyanines

(2-Pyrylo)- and (2-pyrido)(indo)trimethinecyanines containing both electron donor and electron acceptor substituants in the heterocyclic rings have been synthesized. It has been shown that the 4,6-diphenyl-2H-pyran nucleus confers less basicity (electron donor characteristics) than the 1,3,3-trimethylindoline segment. It has also been shown that the introduction of substituents to the heterocyclic residues of unsymmetrical dyes allows one to manipulate their electronic asymmetry over a wide range up to a change in the distribution of charge from one ring to another.For Communication No. 20, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 44–48, January, 1985.     

Pyrylocyanines. 23. 2-Pyrylocarbocyanines with substituents in hetero residues

Symmetric 2-pyrylo- and asymmetric (indo)(2-pyrylo)trimethinecyanines with substituents of different electronic nature in the pyran residue were synthesized. The influence of the conjugation effect and inductive effect on the characteristics of absorption bands of the synthesized dyes was analyzed by a quantum chemical calculation according to a common MO Hückel method.For Communication 22, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii No. 12, pp. 1607–1613, December, 1986.     

Pyrylocyanines. 31. Benzopyrylocarbocyanines with bridged groupings in the chromophore

4,4-Tetramethylene- and 4,4-pentamethylenebisflavylium salts and their sulfur- and selenium-containing analogs were synthesized. Trimethinecyanine dyes with ethylene and trimethylene bridged groupings in the chromophore were obtained from these salts. The factors that affect the color of these dyes were analyzed thoroughly.For Communication 30 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1319–1323, October, 1993.     

Pyrylocyanines. 33. Pyrylocarbocyanines with bridge groups in the chromophore

Salts of 4,4-tetra-, penta-, and hexamethylene-bis-(2,6-diphenylpyrylium) and -thiopyrylium were synthesized and used as the basis for producing trimethylcyanines with ethylene, tri- and tetramethylene bridge groups in the chromophore. Factors influencing the color of these dyes were analyzed. The bis-pyrylium salts were converted to derivatives of pyridine, N-methyl- and N-phenylpyridinium. The structure of the compounds obtained was confirmed by the data of electron spectroscopy and PMR spectroscopy.For communication 32, see [1].Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kiev 252660. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1186–1190, September, 1994. Original article submitted July 13, 1994.     

Pyrylocyanines. 25 Three-dimensional structures of pyrylo-2-monomethinecyanines and their heteroanalogs

Symmetrical tetra-tert-butyl-substituted pyrylo-2- and thiopyrylo-2-monomethinecyanines were synthesized by the condensation of 2-methyl-4,6-di-tert-butylpyrylium and -thiopyrylium salts, respectively, with 2-(alkylthio)-4,6-di-tert-butylpyrylium and -thiopyrylium salts. The pyrylo-2-cyanine obtained was converted to a tetra-tert-butyl-substituted pyrido-2-monomethinecyanine by treatment with methylamine. It was shown by PMR spectroscopy that, in contrast to pyrido-2-monomethinecyanine, which exists in the E,E form, its oxygen-containing analog exists in the E,Z form, and its sulfur-containing analog exists in the Z, Z configuration.See [1] for Communication 24.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 167–171, February, 1988.     

Pyrylocyanines. 22. Styrils derived from methoxy-substituted 4-methylflavylium salts

Some methoxy-substituted styrils of the flavylium series have been synthesized. Simple HMO quantum chemical calculations have shown that the terminal rings in these dyes are largely isolated in consequence of the low order of the C₍₄₎-C₍₎ bond. The latter is responsible for and explains the unexpected effects on the positions and widths of the absorption bands consequent upon the introduction of electrondonor CH₃O groups into the heterocyclic nucleus.For Communication 21, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 886–890, July, 1986.     

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

Symmetrical 4,6,4,6-tetraphenyl-substituted pyrylo-2-, thiopyrylo-2-, and pyrylo-2-cyanines in which both positions of the polymethine chain are bonded to the positions of the heterocyclic residues by ethylene and trimethylene groups were synthesized. The introduction of bridged groupings is accompanied by intensification of the fine structure and bathochromic and hypsochromic effects in the absorption spectra; the former effect is greater and the latter effect is smaller in the case of ethylene groups. The steric and electronic effects of these groups are discussed with the aid of PMR spectroscopy and quantum chemistry.See [1] for Communication 12.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1195–1201, September, 1981.     

Pyrylocyanines. 35. Squarylium dyes based on tert-butyl-substituted pyrylium and thiopyrylium salts

Squarylium dyes based on isomeric di(tert-butyl)methyl-substituted pyrylium, thiopyrylium, and benzopyrylium salts have been synthesized. The dye containing 4, 6-di(tert-butyl)pyrylium residues was converted to its analog with methylpyridinium residues. The PMR and electronic absorption spectra of the dyes obtained were investigated. It was established that deepening of the color from dicarbocyanines to squaraines is characteristic only of dyes containing heterocyclic residues with high or medium electron-donor capacity. For dyes containing heterocyclic residues with low electron-donor capacity the opposite pattern is observed.Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kiev, 253660. Translated from Khimiya Geterotsklicheskikh Soedinenii, No. 8, pp. 1038–1044, August, 1996. Original article submitted May 8, 1996.For communication 34, see [1].     

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.