Direct synthesis of 5-arylethynyl-1,2,4-triazines via direct CH-functionalization

An efficient synthetic approach towards 5-arylethynyl-1,2,4-triazines via direct C-H-functionalization of 5-H-1,2,4-triazines in reaction with lithium acetylenes is reported

New naphtho[1,8-ef]perimidines: synthesis, fluorescence studies and application for detection of nitroanalytes

Received: 15.12.2021. Revised: 20.12.2021. Accepted: 20.12.2021. Available online: 24.12.2021.A rational approach to the synthesis of substituted naphtho[1,8-ef]perimidines based on SN H methodology and cyclization reaction in the series of condensed azines with naphthalene substituents was presented. Photophysical properties of the obtained fluorophores were studied, in particular, green fluorescence in the 485–536 nm range with quantum yield up to 32.4% was detected. HOMO-LUMO energy values and distributions for the new compounds were calculated by the DFT method in comparison with nitroanalytes and perylene. Based on the data obtained, as well as on the results of fluorescence titration, the possibility of using the new diazaperylenes as potential chemosensors for the visual detection of nitrocontaining explosives was shown.This work was supported by Grants Council of the Presi-dent of the Russian Federation № NSh-2700.2020.3

Asymmetrically Functionalized 1,3-Di(2-pyridyl)benzenes: Synthesis and Photophysical Studies

A convenient synthetic approach to asymmetrically functionalized 1,3-di(2-pyridyl)benzenes starting from 3-(3-bromophenyl)-1,2,4-triazines using sequential aza-Diels–Alder reactions and Stille cross-coupling is reported. Photophysical properties of the obtained compounds are studied. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.This work was supported by Russian Science Foundation (Grant № 19-73-10144) and Grants Council of the President of the Russian Federation (no. NSh-2700.2020.3). No other sources of funding were involved

The synthesis of 6-phenoxyphenylamino-2,2'-bipyridines as new fluorophores

New alpha-arylamino-substituted 2,2'-bipyridine type ligands are prepared. © 2019 Author(s)

Synthesis of 2-Phenyl-2-(5-Phenyl-2,2'-Bipyridin-6-yl)-Acetonitrile by «1,2,4-Triazine» Method with Using Autoclave

This work was supported by the Russian Science Foundation (Ref. № 18-73-00301)

The Synthesis of 6-Phenoxyphenylamino-2,2'-Bipyridines as New Fluorophores

This work was supported by the Russian Science Foundation (Ref. № 18-73-10119)

New monomers for (bi)pyridine-containing polymers

Received: 09.09.2020. Accepted: 20.12.2020. Published:30.12.2020.Convenient methods for the synthesis of three monomers based on functionalized (bi)pyridines with using “1,2,4‑triaizine” methodology have been developed.This work was supported by the Russian Foundation for Basic Research (Grant #19‑53‑55002) and Grants Council of the President of the Russian Federation (no. NSh-2700.2020.3)

Two mutually complementary synthetic approaches towards 3‑substituted 3,4‑disubstituted and 1-(2‑pyridyl)-substituted isoquinolines

Received: 08.09.2018. Accepted: 19.10.2018. Published: 31.10.2018.Two mutually complementary synthetic approaches towards 3- and 3,4‑disubstituted 1-(2‑pyridyl) isoquinolines were studied. The aryne-based method was successfully used for the obtaining of the corresponding the 3‑cyano-1-(2‑pyridyl) isoquinolines in one step / pot reaction, while it is unacceptable for the obtaining of other 1-(2‑pyridyl)isoquinolines. The enamine-based approach was successfully applied for the synthesis of other 1-(2‑pyridyl)isoquinolines, while it was unacceptable for the obtaining of 3‑cyano-1-(2‑pyridyl)isoquinolines.This work was supported by the Russian Science Foundation (Reference № 18‑13‑00365)

Improved Method for the Obtaining DTTA-appended 2,2’-bipyridine Ligands for Lanthanide Cations

Received: 25.03.22. Revised: 24.05.22. Accepted: 24.05.22. Available online: 30.05.22.The composition of the reaction mixture after DTTA tert-butyl ester alkylation with 6'-halomethyl-5-phenyl-2,2'-bipyridines was studied. In addition to the target product, DTTA-appended 2,2’-bipyridine, the corresponding 6'-hydroxymethyl-substituted 2,2’-bipyridine and (5'-phenyl-[2,2'-bipyridin]-6-yl)methyl formate were isolated as byproducts in some cases. Finally, an improved procedure for the DTTA tert-butyl ester alkylation with 6'-halomethyl-5-phenyl-2,2'-bipyridines by using Finkelstein reaction was developed.This work was supported by the Russian Science Foundation (grant no. 18-73-10119-P)

3-Aryl-5-aminobiphenyl Substituted [1,2,4]triazolo[4,3-<i>c</i>]quinazolines: Synthesis and Photophysical Properties

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