Egor V. Verbitskiy

Synthesis, Photophysical and Redox Properties of the D–π–A Type Pyrimidine Dyes Bearing the 9-Phenyl-9H-Carbazole Moiety

Novel donor-π-acceptor dyes bearing the pyrimidine unit as an electron-withdrawing group have been synthesized by using combination of two processes, based on the microwave-assisted Suzuki cross-coupling reaction and nucleophilic aromatic substitution of hydrogen. Spectral properties of the obtained dyes in six aprotic solvents of various polarities have been studied by ultraviolet–visible and fluorescence spectroscopy. In contrast to the absorption spectra, fluorescence emission spectra displayed a strong dependence from their solvent polarities. The nature of the observed long wavelength maxima has been elucidated by means of quantum chemical calculations. The electrochemical properties of these dyes have been investigated by using cyclic voltammetry, while their photovoltaic performance was evaluated by a device fabrication study. The experimental and calculation data show that all of the dyes can be regarded as potentially good photosensitizers for dye-sensitized solar cells.

Synthesis and antituberculosis activity of novel 5-styryl-4-(hetero)aryl-pyrimidines via combination of the Pd-catalyzed Suzuki cross-coupling and S(N)(H) reactions.

Combination of the Suzuki cross-coupling and nucleophilic aromatic substitution of hydrogen (SN(H)) reactions proved to be a convenient method for the synthesis of 5-styryl-4-(hetero)aryl substituted pyrimidines from commercially available 5-bromopyrimidine. All intermediate 5-bromo-4-(hetero)aryl substituted pyrimidines and also the targeted 5-styryl-4-(hetero)arylpyrimidines were found to be active in micromolar concentrations in vitro against Mycobacterium tuberculosis H37Rv, avium, terrae, and multi-drug-resistant strain isolated from tuberculosis patients in Ural region (Russia). It has been found that some of these compounds possess a low toxicity and have a bacteriostatic effect, comparable and even higher with that of first-line antituberculosis drugs.

Synthesis and biological evaluation of novel 5-aryl-4-(5-nitrofuran-2-yl)-pyrimidines as potential anti-bacterial agents

A facile two-step synthetic approach to fluorinated and non-fluorinated 5-aryl-4-(5-nitrofuran-2-yl)-pyrimidines from readily available 5-bromo-4-(furan-2-yl)pyrimidine has been developed. All synthesized compounds were screened in vitro for their antibacterial activities against twelve various bacterial strains. It is demonstrated that some of these compounds exhibited significant antibacterial activities against strains Neisseria gonorrhoeae and Staphylococcus aureus, comparable and even higher with that commercial drug Spectinomycin.

Synthesis of 5-(het)aryl- and 4,5-di(het)aryl-2-(thio)morpholinopyrimidines from 2-chloropyrimidine via SNH and cross-coupling reactions

It has been shown that various combinations of nucleophilic aromatic substitution of hydrogen (SNH), SNipso and the microwave-assisted Suzuki cross-coupling reactions are a versatile method for the synthesis of 5-(het)aryl-2-(thio)morpholinopyrimidine and 4,5-di(het)aryl-2-(thio)morpholinopyrimidine derivatives. All synthesized pyrimidines were found to be active in micromolar concentrations in vitro against Mycobacterium tuberculosis H37Rv.

Synthesis, antimycobacterial and antifungal evaluation of some new 1-ethyl-5-(hetero)aryl-6-styryl-1,6-dihydropyrazine-2,3-dicarbonitriles.

The Petasis reaction of 6-hydroxy adducts of 1-alkyl-2,3-dicyano-5-arylpyrazinium salts with trans-styrylboronic acids proved to proceed smoothly at room temperature to give the corresponding 5-(hetero)aryl-6-styryl substituted 1,6-dihydropyrazine derivatives. Also it has been found that C(6) unsubstituted 1,6-dihydro- or 1,4,5,6-tetrahydropyrazine derivatives can be easy prepared in high yields from the corresponding pyrazinium salts by reduction with triethylsilane. All synthesized compounds were screened in vitro for their antifungal activities against seven pathogenic fungal strains and antimycobacterial activities against Mycobacterium tuberculosis H37Rv, avium, terrae and multi-drug-resistant strains isolated from tuberculosis patients in the Ural region (Russia).

2-amino-5-aryl- and 2-amino-5-hetaryl-3-cyano-6-(2-thienyl)pyridines as Organic Dyes for Dye-Sensitized Solar Cells: Synthesis, Quantum-Chemical Calculations, Spectral and Electrochemical Properties

Novel organic dyes containing pyridine ring as the anchoring group with carbazole or triphenylamine substituents were synthesized from available 4-(2-thienyl)pyrimidine using the Kost–Sagitullin rearrangement and Suzuki cross coupling assisted by microwave irradiation. The photophysical (absorption and photoluminescence spectra) and electrochemical properties of these compounds were investigated. The data from quantum calculations show that all of the dyes are potentially good photosensitizers for dye-sensitized solar cells.

Synthesis of 6-thienyl-substituted 2-amino-3-cyanopyridines

An efficient method for the synthesis of 6-thienyl-substituted 2-amino-3-cyanopyridines by the ring transformation in the corresponding pyrimidines was developed. Further modification of the pyridines obtained under conditions of a room temperature aerobic Suzuki reaction in the presence of trans-bis(dicyclohexylamine)palladium(II) acetate as a catalyst was studied

Synthesis and use of polymer-immobilized calix[4]arene derivatives as molecular containers for nitrous gases

Abstract5,11,17,23-Tetrakis(tert-butyl)-25-carboxymethoxy-26,27,28-tris(ethoxycarbonylmethoxy)calix[4]arene immobilized on the polymer support (Merrifield’s resin or poly(ethylene glycol)) was obtained. The presence of ester groups in calixarene does not prevent the formation of a stable colored complex with nitrous gases. Therefore, the synthesized immobilized calix[4]arenes can be used as a material for the detection, isolation, and use of these gases.

9-Ethyl-3-{6-(het)aryl-[1,2,5]oxadiazolo[3,4-b]pyrazin-5-yl}-9H-carbazoles: synthesis and study of sensitivity to nitroaromatic compounds

Abstract5-(9-Ethyl-9H-carbazol-3-yl)-substituted 6-(het)aryl[1,2,5]oxadiazolo[3,4-b]pyrazines were synthesized by direct transition metal-free C—H functionalization in the pyrazine ring. Their photophysical and sensory properties with respect to nitrobenzene and 2,4-dinitrotoluene vapors were studied using a Nitroscan portable detector of nitro-explosive substances (Ekaterinburg, Russia).

Synthesis of dithienoquinazolines from pyrimidines via intramolecular nucleophilic aromatic substitution of hydrogen

The possibility of intramolecular nucleophilic aromatic substitution of hydrogen in the series of 5-[2-(het)aryl-1-benzothiophen-3-yl]-pyrimidines was explored. A convenient method for the synthesis of [1]benzothieno-[3,2-f]thieno[2,3-h]quinazoline and [1]benzothieno-[3,2-f]thieno[3,2-h]quinazoline based on the developed SNH protocol was proposed. The energy parameters (width of the band gap, the energy of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbitals (LUMO)) of benzothieno[3,2-f]-thieno[2,3-h]quinazoline synthesized for the first time were determined based on the data of the absorption spectra and cyclic voltammetry.