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A convenient synthetic route to novel 7-substituted benzo[ f]thieno[3,2- h]quinazoline and 8-substituted benzo[ g, h]dithieno[2,3- e:3′,2′- j]perimidine systems, bearing the fused pyrimidine ring, has been advanced. A commercially available 5-bromopyrimidine was used as the starting material to obtain various polycyclic systems through the sequence of nucleophilic aromatic substitution of hydrogen (the SNH reaction), Suzuki cross-coupling and oxidative photocyclization. Evidence for the structure of benzo[ g, h]dithieno[2,3- e:3′,2′- j]perimidines has been obtained by X-ray crystallographic analysis. Molecular orbital calculations (DFT), as well as redox and optical measurements for all new compounds have been performed. The data show that the reported polycyclic systems have potential for use in organic electronic applications. [ABSTRACT FROM AUTHOR]

A convenient synthetic route to novel thienoacene systems bearing a fused pyrimidine ring has been advanced. The commercially available 5-bromopyrimidine was used as the starting material to obtain various dithienoquinazoline systems through nucleophilic aromatic substitution of hydrogen (the SNH reaction), Suzuki cross-coupling, and oxidative photocyclization. The redox and optical properties of some of the new compounds have been investigated. The data obtained show the potential of dithienoquinazoline systems in organic electronic applications. [ABSTRACT FROM AUTHOR]

Abstract: 5-Bromopyrimidine reacts with 2,2′-bithiophene, [2,2′:5′,2″]terthiophene and 2-phenylthiophene in the presence of a palladium catalyst to give 5-(het)aryl substituted pyrimidines due to the palladium-catalyzed aryl–aryl C–C coupling. However 5-bromo-4-(het)aryl-pyrimidines have been prepared from the same starting materials through the SN H-reaction catalyzed by a Lewis acid. Conditions for both types of reactions were optimized. All components of the reaction mixtures, including by-products, have been elucidated by gas–liquid chromatography/mass-spectrometry. Evidence for the structure of 4- and 5-bithiophenyl-substituted pyrimidines has first been obtained by means of X-ray crystallography analysis. Molecular orbital calculations (TDDFT), as well as the redox and optical measurements for all new compounds have also been performed. [Copyright &y& Elsevier]

The combination of the Suzuki-Miyaura cross-coupling and nucleophilic aromatic substitution of hydrogen reactions is a versatile tool for the syntheses of 4-(1R-pyrrol-2-yl)- and 4-(1R-indol-3-yl)-5-(hetero)aryl-substituted pyrimidines from commercially available 5-bromopyrimidine. The SNH [AE, (addition-elimination)] and SNH [AO, (addition-oxidation)] reactions of 5-bromopyrimidine with pyrroles and indoles were studied by gas chromatography-mass spectrometry. The structures of the intermediate σH adducts as well as the pyrrole-(hetero)arylpyrimidine and indole-(hetero)arylpyrimidine dyads were established for the first time by X-ray crystal structure analysis. [ABSTRACT FROM AUTHOR]

A number of D-π-A-π- D type dyes based on pyrimidines, bearing various electron-donating carbazole and triphenylamine fragments, have been studied as sensing fluorophores. Fluorescence studies demonstrated that the emission of all derivatives in acetonitrile is sensitive to the presence of a number of nitroaromatic benzenoids, including explosives such as 2,4-dinitroanisole, picric acid, styphnic acid, 1,3,5-triethoxy-2,4,6-trinitrobenzene, 2,4-dinitrotoluene and 2,4,6-trinitrotoluene. Detection limits of fluorophores for the explosive compounds were in the range from 2 mM to 29 μM. A selective fluorescence quenching response, including a sharp color change under UV, especially for the trinitrophenolics, makes these fluorophores promising fluorescence sensory materials for nitroaromatic explosives. [ABSTRACT FROM AUTHOR]