Synthesis and spectral-luminescence properties of 2,5-diaryloxazoles that contain a difluoromethylsulfonyl group

A number of 2-(4-difluoromethylsulfonylphenyl)-5-aryloxazoles were synthesized by condensation of 4-difluoromethylsulfonylbenzoyl chloride with -aminomethyl aryl ketones and subsequent cyclodehydration of the resulting amides in sulfuric acid. The spectral-luminescence properties of these products were investigated. The introduction of a difluoromethylsulfonyl group in the 2-phenyl ring of 2,5-diphenyloxazole leads to significant bathochromic and bathofluoric effects and an increase in the quantum yields and photostabilities of the compounds obtained. Complication of the structure of the 5-phenyl ring is accompanied by a further long-wave shift of the absorption and fluorescence spectra without substantial changes in the fluorescence quantum yields. A positive solvatochromism effect is displayed distinctly in the fluorescence spectra of the compounds obtained on passing to polar solvents; this effect increases markedly as the polarity of the solvent increases.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1042–1046, August, 1982.     

Quinaldine derivatives with fluorine-containing substituents and cyanine dyes based on them

Condensation of fluorine-containing anilines with paraldehyde gave quinaldine derivatives with CF₃, CF₃S, and CF₃SO₂ groups in the 6 position, from which carbocyanine, merocyanine, and styryl dyes were synthesized. Fluorine-containing groups lower the basicity of quinaldine by 0.7–2.0 pK_a units and lead to deepening of the color of the dyes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 76–78, January, 1978.     

1,4-Benzodiazepines and their cyclic homologs and analogs

5-Difluoromethylsulfonyl-2-aminobenzophenone was synthesized by condensation of p-difluoromethylsulfonylaniline with benzoyl chloride. 5-Difluoromethoxy- and 5-difluoromethylthio-2-aminobenzophenones were obtained by condensation of phenylacetonitrile with the appropriate p-substituted nitrobenzenes and subsequent reduction of the resulting anthranils. 7-Difluoromethoxy-, 7-difluoromethylthio-, and 7-difluoromethylsulfonyl-5-phenyl-1,2-dihydro-3H-1,4-benzodiazepin-2-ones were obtained by the successive action of bromoacetyl bromide and ammonia on the 2-aminobenzophenone derivatives or by reaction of 2-aminobenzophenones with aminoacetyl chloride hydrochloride. The structure of the 1,4-benzodiazepines was confirmed by a study of the UV, IR, PMR, and mass spectra.     

Heterodiene synthesis

2-Phenyl-4,6-diaryl-1,2-dihydro-sym-triazines react with hexafluoro-2-butyne as a dienophile to give 4,5-bis(trifluoromethyl)-2,6-diarylpyrimidines.See [1] for communication V.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 122–123, January, 1977.     

Reaction of SeOCF3 and SeO2CF3 groups with π-electron systems in ground and excited states

The dipole moments and ultraviolet spectra were measured for selenium compounds containing SeOCF₃ and SeO₂CF₃ groups. It is shown that in the ground state the SeO₂CF₃ group has a greater tendency toward conjugation with the -electron system of the benzene ring thandoes the SeOCF₃ group. In the ground state, selenium compounds containing SeOCF₃ and SeO₂CF₃ groups have a smaller conjugation effect than corresponding sulfur compounds. Oxidation of SeCF₃ to SeOCF₃ decreases the degree to which the uncollectivized electrons of selenium take part in conjugation with electron-accepting groups. In the unexcited state the free electrons of selenium in SeCH₃ and SeCF₃ groups are more mobile than those of sulfur in SCH₃ and SCF₃ groups, and the * level of the Se=O groups is lower than that of the S=O group.