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A simple synthetic route to poorly available polycyclic systems with a [1,2,5]oxadiazolo-[3,4-b]quinoxaline backbone has been developed, which is based on the sequence of nucleophilic aromatic substitution of hydrogen and the Scholl cross-coupling. According to the data from electrochemical and photophysical measurements, the synthesized compounds can be potentially considered as the narrow-gap (from 1.97 to 2.34 eV) n-type organic semiconductors, the energy levels of which are comparable to those of top commercially available electronic semiconductors. [ABSTRACT FROM AUTHOR]

Poly[4-(1′-pyrenyl)styrene was synthesized for the first time, its photophysical properties were explored, and among them, the fluorescence with a high absolute quantum yield was discovered. Data acquired using the fluorescent titration revealed the opportunity to detect model nitroaromatic explosives at detection limits varying in the range from 10−6 to 10−7 mol L−1. The results reported herein for the homopolymer were compared with the corresponding data for poly[styrene-co-4-(1′-pyrenyl)styrene] copolymer synthesized previously. [ABSTRACT FROM AUTHOR]

A simple synthetic route to hard-to-prepare polycyclic (hetero)aromatic compounds with the [1,2,5]chalcogenodiazolo[3,4-b]pyrazine scaffold was developed based on the intramolecular nucleophilic aromatic hydrogen substitution reaction. Electrochemical and photophysical measurements demonstrated that the synthesized polycyclic systems can be considered as narrow-bandgap (from 1.25 to 1.44 eV) n-type organic semiconductors, the energy levels of which are comparable to those of commercially available electronic semiconductors. [ABSTRACT FROM AUTHOR]

The possibility of using push-pull systems based on furazanopyrazine in organic light-emitting diodes (OLEDs) and photovoltaic film devices was shown for the first time. The emission of all the obtained light-emitting diodes had a yellow-green color, and a maximum brightness of 45600 cd m−2 was achieved at a maximum current efficiency of 2.9 cd A−1. It was determined that the mobility of charge carriers measured in different current modes for these push-pull systems ranged from 10−4 to 4 · 10−6 cm2 V−1 s−1, considerably exceeding the values of the well-known compound Spiro-MeOTAD, widely used in high-efficiency photovoltaic devices. [ABSTRACT FROM AUTHOR]

A convenient method was developed for the synthesis of 4-arylstyrenes containing residues of polycyclic aromatics or triphenylamine. The method is based on the microwave-assisted Suzuki—Miyaura cross-coupling reaction. The optical properties of the compounds were studied. High fluorescence quantum yields of 4-arylstyrenes make them promising monomers for the synthesis of polymers that can find use as photovoltaic and sensor materials. [ABSTRACT FROM AUTHOR]

A method for the synthesis of previously unknown 5-arylamino-substituted 4-(5-aryloxy-furan-2-yl)pyrimidines containing methyl and methoxy groups at different positions of the aryl substituents was developed. The method is based on the combination of the Buchwald-Hartwig cross-coupling reaction with various anilines and nucleophilic substitution of the nitro group by phenolate anions. All the new compounds were screened against 15 different pathogenic bacterial strains. 4-[5-(3,4,5-Trimethoxyphenoxy)furan-2-yl]-substituted pyrimidines were found to possess high antibacterial activity against gonococcal infections, in some cases ten times higher than that of the commercial drug Spectinomycin. [ABSTRACT FROM AUTHOR]

The properties of pyrimidine and pyrazine derivatives responsible for the existence of antituberculosis activity are considered. Examples of synthesis and biological activity of the most promising compounds containing the pyrimidine or pyrazine rings in the molecular structure are presented. [ABSTRACT FROM AUTHOR]

5-(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). [ABSTRACT FROM AUTHOR]

The O- and C-adducts of 5-aryl and 5-hetaryl-2,3-dicyano-1-ethylpyrazinium salts are hidden sources of ylides, which can be used for the cyclization with arylacetylenes giving rise to pyrrolo[1,2- a]pyrazines. [ABSTRACT FROM AUTHOR]

A simple synthetic route to poorly available polycyclic systems with a [1,2,5]oxadiazolo-[3,4-b]quinoxaline backbone has been developed, which is based on the sequence of nucleophilic aromatic substitution of hydrogen and the Scholl cross-coupling. According to the data from electrochemical and photophysical measurements, the synthesized compounds can be potentially considered as the narrow-gap (from 1.97 to 2.34 eV) n-type organic semiconductors, the energy levels of which are comparable to those of top commercially available electronic semiconductors. [ABSTRACT FROM AUTHOR]