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Functionalized perfluoroalkyl lithium β-diketonates (LiL) react with lanthanide(III) salts (Ln = Eu, Gd, Tb, Dy) in methanol to give heterobimetallic Ln-Li complexes of general formula [(LnL3)(LiL)(MeOH)]. The length of fluoroalkyl substituent in ligand was found to affect the crystal packing of complexes. Photoluminescent and magnetic properties of heterobimetallic β-diketonates in the solid state are reported. The effect of the geometry of the [LnO8] coordination environment of heterometallic β-diketonates on the luminescent properties (quantum yields, phosphorescence lifetimes for Eu, Tb, Dy complexes) and single-ion magnet behavior (Ueff for Dy complexes) is revealed. [ABSTRACT FROM AUTHOR]

The C−N coupling of 1,2,4‐triazolo[1,5‐a]pyrimidin‐7‐ones with 1‐adamantanol/1‐bromoadamantane leads to 1,2,4‐triazolo[4,3‐a]pyrimidinium‐5‐olates, which are represented as mesomeric betaines (MBs). The formation of MBs involves not only N‐alkylation of heterocyclic framework but also the rearrangement leading to a change in the type of fusion between pyrimidine and 1,2,4‐triazole fragments. The structures of the obtained products were confirmed by the X‐ray analysis and measurements of 13C−13C (JCC) coupling constants in the 1D 13C NMR spectra of selectively 13C‐labeled samples. Treatment of the betaines with lithium bis(trimethylsilyl)amide (LiHMDS) gave anionic carbenes, which were detected by 13C NMR spectroscopy and were trapped by reactions with phenyl isothiocyanate and sulfur. Density functional theory (DFT) and the quantum theory of atoms in molecules (QTAIM) analyses allowed for an insight into the electronic structure of the obtained betaines and N‐heterocyclic carbene derivatives. [ABSTRACT FROM AUTHOR]

A sodium salt of 2-(fur-2-yl)-6-nitro-1,2,4-triazolo[1,5-a]pyrimidin-7-one as a close structural analogue of ZM-241385 was obtained. This heterocycle can serve as an effector for A2a adenosine receptors and possesses antiseptic activity. The structures of compounds were confirmed based on the data of 1H, 13C NMR spectroscopy, IR spectroscopy, and an elemental analysis. The structure of sodium salt 2-furyl-6-nitro-1,2,4-triazolo[1,5-a]pyrimidin-7-one was confirmed by an X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

Amino-[1,1′]-biphenyl-containing 3-aryl-[1,2,4]triazolo[4,3-c]quinazoline derivatives with fluorescent properties have been designed and synthesized. The type of annelation of the triazole ring to the pyrimidine one has been unambiguously confirmed by means of an X-ray diffraction (XRD) method; the molecules are non-planar, and the aryl substituents form the pincer-like conformation. The UV/Vis and photoluminescent properties of target compounds were investigated in two solvents of different polarities and in a solid state. The samples emit a broad range of wavelengths and display fluorescent quantum yields of up to 94% in toluene solutions. 5-(4'-Diphenylamino-[1,1′]-biphenyl-4-yl)-3-(4-(trifluoromethyl)phenyl)-[1,2,4]triazolo[4,3-c]quinazoline exhibits the strongest emission in toluene and a solid state. Additionally, the solvatochromic properties were studied for the substituted [1,2,4]triazolo[4,3-c]quinazolines. Moreover, the changes in absorption and emission spectra have been demonstrated upon the addition of water to MeCN solutions, which confirms aggregate formation, and some samples were found to exhibit aggregation-induced emission enhancement. Further, the ability of triazoloquinazolines to detect trifluoroacetic acid has been analyzed; the presence of TFA induces changes in both absorption and emission spectra, and acidochromic behavvior was observed for some triazoloquinazoline compounds. Finally, electronic-structure calculations with the use of quantum-chemistry methods were performed for synthesized compounds. [ABSTRACT FROM AUTHOR]

A series of novel 4-(aryl)-benzo[4,5]imidazo[1,2-a]pyrimidine-3-carbonitriles were obtained through the Povarov (aza-Diels–Alder) and oxidation reactions, starting from benzimidazole-2-arylimines. Based on the literature data and X-ray diffraction analysis, it was discovered that during the Povarov reaction, [1,3] sigmatropic rearrangement leading to dihydrobenzimidazo[1,2-a]pyrimidines took place. The structures of all the obtained compounds were confirmed based on the data from 1H- and 13C-NMR spectroscopy, IR spectroscopy, and elemental analysis. For all the obtained compounds, their photophysical properties were studied. In all the cases, a positive emission solvatochromism with Stokes shifts from 120 to 180 nm was recorded. Aggregation-Induced Emission (AIE) has been illustrated for compound 6c using different water fractions (fw) in THF. The compounds 6c and 6f demonstrated changes in emission maxima or/and intensities after mechanical stimulation. [ABSTRACT FROM AUTHOR]

Design and synthesis of 2-(aryl/thiophen-2-yl)quinazolin-4(3H)-ones and 4-cyano-2-arylquinazolines with Et2N-, Ph2N- or carbazol-9-yl- electron donating fragment are described. The key photophysical properties of these compounds have been studied by UV/Vis absorption and fluorescence spectroscopy in solvents of different polarity (toluene and MeCN). 2-(Aryl/thiophen-2-yl)quinazolin-4(3H)-ones show fluorescence in blue-green region in toluene solution with quantum yields up to 89% in the case of 2-(4'-N,N-diphenylamino[1,1'-biphenyl]-4-yl)-quinazolin-4(3H)-one. Moreover, triphenylamino derivative based on quinazolin-4(3H)-one with para-phenylene linker displays the highest quantum yield of 40% in powder. The fluorescence QY of Et2N and Ph2N derivatives decrease when going from toluene to MeCN solution, whereas carbazol-9-yl counterparts demonstrate strengthening of intensity that emphasizes the strong influence of donor fragment nature on photophysical properties. 4-Cyanoquinazolines are less emissive in both solvents, as well as, in solid state. The introduction of cyano group into position 4 leads to orange/red colored powder and dual emission bands. Some molecules demonstrate the increase in emission intensity upon addition of water to MeCN solution. According to frontier molecular orbitals (HOMO, LUMO) calculations, the energy gap of 4-cyanoquinazoline decreases by more than 1 eV compared to quinazolin-4-one, that is consistent with experimental data. [ABSTRACT FROM AUTHOR]

Interaction of 3-(α- or γ-R-pyridin-2-yl)-1,2,4-triazines (R = Me, CO2Me) with arynes affords either the domino-transformation products, pyrido[1,2-a]indoles, or Diels-Alder reaction ones, isoquinolines. The influence of the nature and/or position of the substituent on the reaction pathway is discussed. [ABSTRACT FROM AUTHOR]

An operationally facile and high yielding one‐pot protocol has been developed for the preparation of pyridines appended with pyrazole via NH linker. This protocol includes SNipso/aza‐Diels‐Alder reactions in up to 54 % yields starting from 1,2,4‐triazine precursors. All the synthesized compounds have been evaluated for their in silico activity against JAK1, SYK, and FAK1 kinases. The most promising compound was tested in vitro using A‐172, Hs578T, and HepG2 cancer cell lines and exhibited considerable cytotoxicity with IC50 values <50 μM in A‐172 and HepG2 cell lines. Anticancer in vitro activity correlates well with the predicted in silico data. [ABSTRACT FROM AUTHOR]