Pyrimido[5,4-]azolo[1,5-]pyrimidines and pyrimido[4,5-][1,2,4]triazolo[5,1-][1,2,4]triazines: multi-component synthesis and cytotoxic activity.

A multi-component method for the synthesis of pyrimido[5,4-]azolo[1,5-]pyrimidines and pyrimido[4,5-][1,2,4]triazolo[5,1-][1,2,4]triazines has been developed. It was shown that vicinal amino-nitrile and amino-ethoxycarbonyl derivatives of azolo[1,5-]pyrimidines and azolo[5,1-][1,2,4]triazines were converted to tricyclic heterocycles in the "AcOH-RC(OEt)-amine" system. Reaction conditions were optimized, patterns of this process were investigated, and intermediates were isolated.

Design, Synthesis, and Photophysical Properties of 5-Aminobiphenyl Substituted [1,2,4]Triazolo[4,3-]- and [1,2,4]Triazolo[1,5-]quinazolines.

Two series of novel [1,2,4]triazolo[4,3-]- and [1,2,4]triazolo[1,5-]quinazoline fluorophores with 4'-amino[1,1']-biphenyl residue at position 5 have been prepared via Pd-catalyzed cross-coupling Suzuki-Miyaura reactions. The treatment of 2-(4-bromophenyl)-4-hydrazinoquinazoline with orthoesters in solvent-free conditions or in absolute ethanol leads to the formation of [4,3-]-annulated triazoloquinazolines, whereas [1,5-] isomers are formed in acidic media as a result of Dimroth rearrangement. A 1D-NMR and 2D-NMR spectroscopy, as well as a single-crystal X-ray diffraction analysis, unambiguously confirmed the annelation type and determined the molecular structure of -bromophenyl intermediates and target products.

Reconstructive Methodology in the Synthesis of 2-Aminopurine.

A fundamentally new synthetic approach to the synthesis of 2-aminopurine has been developed. It consists in the combination of the creation of a condensed polyazotic heterocyclic tetrazolopyrimidine structure, its transformation into triaminopyrimidine, and its subsequent cyclization into 2-aminopurine. The structure of the obtained compounds was established based on spectral characteristics, and the structure of the intermediate compound was established directly by X-ray diffraction analysis.

Synthesis and Assessment of Antiplatelet and Antithrombotic Activity of 4-Amino-Substituted 5-Oxoproline Amides and Peptides.

Venous thromboembolism is a serious problem because it significantly increases the risk of developing vascular complications in elderly patients with obesity or immobilization, cancer, and many other diseases. Thus, there is a need to study new therapeutic strategies, including new medicinal agents for the efficient and safe correction of thrombus disorders. In this work, we have synthesized a number of new amides and peptides of 4-amino-5-oxoprolines and studied their antiplatelet and antithrombotic activity in experiments in vitro and in vivo.

Exploring Three Avenues: Chemo- and Regioselective Transformations of 1,2,4-Triketone Analogs into Pyrazoles and Pyridazinones.

A convenient approach to substituted pyrazoles and pyridazinones based on 1,2,4-triketones is presented. Chemo- and regiocontrol in condensations of -Bu, Ph-, 2-thienyl-, and COEt-substituted 1,2,4-triketone analogs with hydrazines are described. The direction of preferential nucleophilic attack was shown to be switched depending on the substituent nature in triketone as well as the reaction conditions.

Perfluoroalkyl Chain Length Effect on Crystal Packing and [LnO] Coordination Geometry in Lanthanide-Lithium β-Diketonates: Luminescence and Single-Ion Magnet Behavior.

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 [(LnL)(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.

Multicomponent Domino Cyclization of Ethyl Trifluoropyruvate with Methyl Ketones and Amino Alcohols as A New Way to γ-Lactam Annulated Oxazacycles.

A new route to bicyclic γ-lactams was found, which was proposed as a three-component cyclization of ethyl trifluoropyruvate with methyl ketones and 1,2-, 1,3-amino alcohols. As a result, a series of trifluoromethyl-substituted tetrahydropyrrolo [2,1-]oxazol-5-ones and tetrahydropyrrolo[2,1-][1,3]oxazine-6-ones was synthesized, in which the substituent at the nodal carbon atom was varied. The introduction of a twofold excess of ethyl trifluoropyruvate in reactions with amino alcohols and acetone made it possible to obtain the same bicycles, but functionalized with a hydroxyester fragment, which are formed due to four-component interactions of the reagents.

3-Aryl-5-aminobiphenyl Substituted [1,2,4]triazolo[4,3-]quinazolines: Synthesis and Photophysical Properties.

Amino-[1,1']-biphenyl-containing 3-aryl-[1,2,4]triazolo[4,3-]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.

5-Amino-2-aryl-2H-1,2,3-triazole-4-carboxamides: Unique AIEE-gens and selective Hg fluorosensors.

A series of fluorescent sensors based on small molecule were designed and fully characterised, demonstrating AIEE effect and revealing an outstanding ability to selectively detect Hg ions. The structural and electronic properties were studied through quantum chemical calculations at (Time-Dependent) Density Functional Theory ((TD)-DFT) level. Carboxamides of 2-Aryl-1,2,3-Triazoles (CATs) showed significant differences in their photophysical properties depending on the structure of the substituent at amino function on the C5-atom in the heterocycle.

Mesomeric Betaines Based on Adamantylated 1,2,4-Triazolo[4,3-a]pyrimidin-5-ones: Synthesis, Structure and Conversion into Anionic N-Heterocyclic Carbenes.

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 C- C (J ) coupling constants in the 1D C NMR spectra of selectively C-labeled samples.

Synthesis, Fungicidal Activity and Plant Protective Properties of 1,2,3-Thiadiazole and Isothiazole-Based -acyl--arylalaninates.

The addition of active groups of known fungicides, or systemic acquired resistance inducers, into novel compound molecules to search for potential antifungal compounds is a popular and effective strategy. In this work, a new series of -acyl--arylalanines was developed and synthesized, in which 1,2,3-thiadiazol-5-ylcarbonyl or 3,4-dichloroisothiazol-5-ylcarbonyl (fragments from synthetic plant resistance activators tiadinil and isotianil, respectively) and a fragment of -arylalanine, the toxophoric group of acylalanine fungicides. Several new synthesized compounds have shown moderate antifungal activity against fungi in vitro, such as , and .

Push-Pull Structures Based on 2-Aryl/thienyl Substituted Quinazolin-4(3)-ones and 4-Cyanoquinazolines.

Design and synthesis of 2-(aryl/thiophen-2-yl)quinazolin-4(3)-ones and 4-cyano-2-arylquinazolines with EtN-, PhN- 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(3)-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(3)-one.

Direct C-H/C-H Coupling of the Azoloannulated Pteridines with Electron Rich (Hetero)Aromatic Compounds.

The methods for modification of azoloannulated pteridines with (hetero)aromatic nucleophiles using a nucleophilic substitution of hydrogen (S) methodology have been developed in this work. Stable intermediate σ-adducts, as well as products of an unexpected intramolecular rearrangement of diadducts, have been isolated and characterized. The potential of the proposed approach for obtaining donor-acceptor systems, in which the pteridine fragment of the molecule acts as an acceptor, was demonstrated.

Copper(ii) complexes with terpene derivatives of ethylenediamine: synthesis, and antibacterial, antifungal and antioxidant activity.

The synthesis of new chiral copper(ii) complexes with terpene derivatives of ethylenediamine and the results of studying their antibacterial, antifungal and antioxidant activity are discussed. All studied copper complexes (1-4) showed significantly higher antifungal activity against the strains of , and compared to the activity of the clinical antifungal drug amphotericin. High antibacterial activity of copper complexes with terpene derivatives of ethylenediamine was revealed against the (MRSA) strain, which is resistant to the reference antibiotic ciprofloxacin.

Unsymmetrical Trifluoromethyl Methoxyphenyl β-Diketones: Effect of the Position of Methoxy Group and Coordination at Cu(II) on Biological Activity.

Copper(II) complexes with 1,1,1-trifluoro-4-(4-methoxyphenyl)butan-2,4-dione (H) were synthesized and characterized by elemental analysis, FT-IR spectroscopy, and single crystal X-ray diffraction. The biological properties of H and -[Cu()(DMSO)] () were examined against Gram-positive and Gram-negative bacteria and opportunistic unicellular fungi. The cytotoxicity was estimated towards the HeLa and Vero cell lines.

New heteroanalogs of tricyclic ascidian alkaloids: synthesis and biological activity.

Heteroanalogs of ascidian alkaloids have been synthesized, and for the first time 10 different types of saturated carbo- and heteroannulated pyridones have been obtained. A new method for the formation of decahydro[1,3]oxazolo[2,3-]quinoline and octahydro-5-cyclopenta[][1,3]oxazolo[3,2-]pyridine was proposed. The synthesis of these heterocycles is based on the three-component cyclization of trifluoroacetoacetic ester and cycloketones with 1,2- and 1,3-dinucleophiles.

Photophysics, photochemistry and bioimaging application of 8-azapurine derivatives.

New 2-aryl-1,2,3-triazolopyrimidines were designed, synthesized, and characterized. Their optical properties were thoroughly studied in the solid phase, in solution and in a biological environment. Density Functional Theory (DFT) based calculations were performed, including the molecular geometry optimization for both the ground state and the first singlet excited state, the prediction of the UV-Vis absorption and fluorescence spectra, the determination of the molecular electrostatic properties and the solvent effect on the optical properties.

Synthesis and antiviral activity of nonannulated tetrazolylpyrimidines.

Nonannulated tetrazolylpyrimidines in the structure of which the heterocyclic fragments are separated by hydrazinocarbonylmethyl, methylpyrazolyl groups or a sulfur atom were synthesized. Some of these compounds showed moderate activity against H1N1 subtype of influenza A virus. The selectivity index of the anti-influenza action of {5-[(4,6-dimethylpyrimidin-2-yl)sulfanyl]-1-tetrazol-1-yl}acetic acid, which has very low cytotoxicity, was twice as high as the selectivity index of the reference drug rimantadine.

Methods of Synthesis and Antiviral Activity of New 4-Alkyl-3-Nitro-1,4-Dihydroazolo[5,1-][1,2,4]Triazin-4-ols.

Unlabelled: An azo coupling reaction of α-nitro ketones with 5-diazoazoles was used to obtain 4-alkyl-3-nitro-1,4-dihydroazolo[5,1-][1,2,4]triazines, which were characterized with respect to their antiviral activity against influenza and Coxsackie B3 viruses.

Supplementary Information: The online version contains supplementary material available at 10.1007/s10593-021-02926-2.

Two Approaches for the Synthesis of Fused Dihydropyridines via a 1,6-Electrocyclic Reaction: Fluorescent Properties and Prospects for Application.

Reactions of penta-2,4-dienethioamides with acetylenedicarboxylic acid, methyl and ethyl esters, and methyl propiolate were systematically studied, and a number of new 2,3-dihydro-5-thiazolo[3,2-]pyridines (DTPs) and 4,6-pyrido[2,1-][1,3]thiazines (PTZs) were prepared. A possible mechanism for a multistep domino transformation is suggested, and the key step is the 1,6-electrocyclic reaction. An additional alternative method for the synthesis of new heterocyclic systems was achieved.

The different modes of chiral [1,2,3]triazolo[5,1-b][1,3,4]thiadiazines: crystal packing, conformation investigation and cellular activity.

The crystal structures of four new chiral [1,2,3]triazolo[5,1-b][1,3,4]thiadiazines are described, namely, ethyl 5'-benzoyl-5'H,7'H-spiro[cyclohexane-1,6'-[1,2,3]triazolo[5,1-b][1,3,4]thiadiazine]-3'-carboxylate, CHNOS, ethyl 5'-(4-methoxybenzoyl)-5'H,7'H-spiro[cyclohexane-1,6'-[1,2,3]triazolo[5,1-b][1,3,4]thiadiazine]-3'-carboxylate, CHNOS, ethyl 6,6-dimethyl-5-(4-methylbenzoyl)-6,7-dihydro-5H-[1,2,3]triazolo[5,1-b][1,3,4]thiadiazine-3-carboxylate, CHNOS, and ethyl 5-benzoyl-6-(4-methoxyphenyl)-6,7-dihydro-5H-[1,2,3]triazolo[5,1-b][1,3,4]thiadiazine-3-carboxylate, CHNOS. The crystallographic data and cell activities of these four compounds and of the structures of three previously reported similar compounds, namely, ethyl 5'-(4-methylbenzoyl)-5'H,7'H-spiro[cyclopentane-1,6'-[1,2,3]triazolo[5,1-b][1,3,4]thiadiazine]-3'-carboxylate, CHNOS, ethyl 5'-(4-methoxybenzoyl)-5'H,7'H-spiro[cyclopentane-1,6'-[1,2,3]triazolo[5,1-b][1,3,4]thiadiazine]-3'-carboxylate, CHNOS, and ethyl 6-methyl-5-(4-methylbenzoyl)-6-phenyl-6,7-dihydro-5H-[1,2,3]triazolo[5,1-b][1,3,4]thiadiazine-3-carboxylate, CHNOS, are contrasted and compared. For both crystallization and an MTT assay, racemic mixtures of the corresponding [1,2,3]triazolo[5,1-b][1,3,4]thiadiazines were used.

Rearrangement of 7-Aryloxazolo[5,4-]pyridines to Benzo[][1,7]naphthyridine-4(3)-ones and Thieno[3,2-][1,7]naphthyridine-6(7)-ones.

In this work, we describe the development of the rearrangement for 7-aryl-substituted oxazolo[5,4-]pyridines treated with aluminum chloride into synthetically hard-to-reach benzo[][1,7]naphthyridinones. The discovered rearrangement is applied to a variety of electron-rich (hetero)arene substrates. It offers the advantages of mild conditions (90 °C temperature), fast reaction rates (<4 h), compatibility with air moisture, and the use of inexpensive commercial reagents.

Dibenzo[]furazano[3,4-]quinoxalines: Synthesis by Intramolecular Cyclization through Direct Transition Metal-Free C-H Functionalization and Electrochemical, Photophysical, and Charge Mobility Characterization.

Herein, we describe the synthesis of unsymmetrically substituted dibenzo[]furazano[3,4-]quinoxalines by intramolecular cyclization through direct transition metal-free C-H functionalization. The electrochemical and photophysical properties for several polycycles have been measured. In thin films of the dibenzo[]furazano[3,4-]quinoxalines, hole mobility is in the order of 10 cm V s.