Search results for: Tetyana Beryozkina

Items from 1 to 18 out of 18 results

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The Rich Chemistry Resulting from the 1,3‐Dipolar Cycloaddition Reactions of Enamines and Azides

Vasiliy A. Bakulev, Tetyana Beryozkina, Joice Thomas, Wim Dehaen

European Journal of Organic Chemistry > 2018 > 3 > 262 - 294

Enamines exhibit exceptionally high reactivity in their 1,3‐dipolar cycloaddition reactions with azides in comparison with other dipolarophiles. This review includes the reactions of various types of enamines with azides of different nature, including catalytic processes. The initial products of the reaction, 1,2,3‐triazolines, are generally unstable and very reactive compounds which are prone to...

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A novel heterocyclic compound improves working memory in the radial arm maze and modulates the dopamine receptor D1R in frontal cortex of the Sprague-Dawley rat

Ahmed M. Hussein, Yogesh D. Aher, Predrag Kalaba, Nilima Y. Aher, more

Behavioural Brain Research > 2017 > 332 > C > 308-315

A series of compounds have been shown to enhance cognitive function via the dopaminergic system and indeed the search for more active and less toxic compounds is continuing. It was therefore the aim of the study to synthetise and test a novel heterocyclic compound for cognitive enhancement in a paradigm for working memory. Specific and effective dopamine re-uptake inhibition DAT (IC50=4,1±0,8μM) made...

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High Conductivity in Molecularly p‐Doped Diketopyrrolopyrrole‐Based Polymer: The Impact of a High Dopant Strength and Good Structural Order

Yevhen Karpov, Tim Erdmann, Ivan Raguzin, Mahmoud Al‐Hussein, more

Advanced Materials > 28 > 28 > 6003 - 6010

[3]‐Radialene‐based dopant CN6‐CP studied herein, with its reduction potential of +0.8 versus Fc/Fc+ and the lowest unoccupied molecular orbital level of −5.87 eV, is the strongest molecular p‐dopant reported in the open literature, so far. The efficient p‐doping of the donor–acceptor dithienyl‐diketopyrrolopyrrole‐based copolymer having the highest unoccupied molecular orbital level of −5.49 eV is...

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A catalyst and additive-free three-component reaction of highly electrophilic azides with cyclic ketones and cycloaliphatic amines. Synthesis of novel N-heteroaryl amidines

Ilya Efimov, Nikolai Beliaev, Tetyana Beryozkina, Pavel Slepukhin, more

Tetrahedron Letters > 2016 > 57 > 18 > 1949-1952

Highly electrophilic 5-azido-1-methyl-4-nitro-1H-imidazole and sulfonyl azides were demonstrated to react with alicyclic amines and cyclic ketones in the absence of any catalyst or additive to afford novel N-(4-nitroimidazol-5-yl)- or N-sulfonylamidines respectively. Based on single crystal X-ray analysis, a revision of the previously reported data of Gao and co-workers on the direction of the reaction...

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Reactions of Thioacetamide Derivatives with Sulfonyl Azides: An Approach to Active‐Methylene N‐Sulfonylacetamidines

Lidia Dianova, Vera Berseneva, Tetyana Beryozkina, Ilya Efimov, more

European Journal of Organic Chemistry > 2015 > 31 > 6917 - 6923

Reactions of functionalized [CN, CO₂Et, C(O)NHR, C(S)NR¹R²] derivatives of thiomalonic acid and 2‐arylthioacetamides with sulfonyl azides were shown to give active‐methylene N‐sulfonylamidines in 62–98 % yields. Various procedures for the reactions, including the use of pyridine, boiling ethanol, and water, or running the reactions in the absence of a base and solvent at 80 °C, were carried out and...

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A novel transformation of β-1,2,3-thiadiazol-5-yl enamines into thieno[2,3-d]pyridazines

Yuri Rozin, Sergey Zhidovinov, Tetyana Beryozkina, Yuri Shafran, more

Tetrahedron Letters > 2015 > 56 > 12 > 1545-1547

Reactions of β-1,2,3-thiadiazol-5-yl enamines with acetyl chloride in 1,4-dioxane lead to the formation of either dienamines or novel thieno[2,3-d]pyridazines depending on the time and reaction temperature. Conditions were found for the selective synthesis of thieno[2,3-d]pyridazines. A plausible mechanism involves formation of C–S and C–C bonds and a novel ring rearrangement of 5-vinyl-1,2,3-thiadiazoles...

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Reactions of β‐Azolylenamines with Sulfonyl Azides as an Approach to N‐Unsubstituted 1,2,3‐Triazoles and Ethene‐1,2‐diamines

Ilya Efimov, Vasiliy Bakulev, Nikolai Beliaev, Tetyana Beryozkina, more

European Journal of Organic Chemistry > 2014 > 17 > 3684 - 3689

The reactions of β‐azolylenamines 1 with sulfonyl azides 2 in acetonitrile furnished 1H‐4‐(azol‐5‐yl)‐1,2,3‐triazoles 3 in yields of 52–93 %. β‐Benzoylenaminones and β‐nitroenamine of type 1 also reacted with tosyl azide to form the same type of products 3, proving the generality and efficiency of the method for the synthesis of N‐unsubstituted 1,2,3‐triazoles. On the other hand, the reactions of...

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Palladium‐Catalyzed Chain‐Growth Polycondensation of AB‐type Monomers: High Catalyst Turnover and Polymerization Rates

Roman Tkachov, Volodymyr Senkovskyy, Tetyana Beryozkina, Kseniya Boyko, more

Angewandte Chemie > 126 > 9 > 2434 - 2439

Chain‐growth catalyst‐transfer polycondensations of AB‐type monomers is a new and rapidly developing tool for the preparation of well‐defined π‐conjugated (semiconducting) polymers for various optoelectronic applications. Herein, we report the Pd/PtBu₃‐catalyzed Negishi chain‐growth polycondensation of AB‐type monomers, which proceeds with unprecedented TONs of above 100 000 and TOFs of up to 280...

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Palladium‐Catalyzed Chain‐Growth Polycondensation of AB‐type Monomers: High Catalyst Turnover and Polymerization Rates

Roman Tkachov, Volodymyr Senkovskyy, Tetyana Beryozkina, Kseniya Boyko, more

Angewandte Chemie International Edition > 53 > 9 > 2402 - 2407

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A Core‐First Preparation of Poly(3‐alkylthiophene) Stars

Volodymyr Senkovskyy, Tetyana Beryozkina, Vera Bocharova, Roman Tkachov, more

Macromolecular Symposia > 291-292 > 1 > 17 - 25

A new and facile method for the preparation of mono‐ and hexa‐functional Ni‐bipyridyl‐based initiators that mediate Kumada polycondensation of 2‐bromo‐5‐chloromagnesio‐3‐hexylthiophene into head‐to‐tail regioregular poly(3‐hexylthiophene), P3HT, has been developed. An important advantage of the catalytic system presented herein is the ease of the preparation of a number of Ar‐Nibipy‐Br initiators...

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“Hairy” Poly(3-hexylthiophene) Particles Prepared via Surface-Initiated Kumada Catalyst-Transfer Polycondensation

Volodymyr Senkovskyy, Roman Tkachov, Tetyana Beryozkina, Hartmut Komber, more

Journal of the American Chemical Society > 2009 > 131 > 45 > 16445 - 16453

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Surface Engineering Using Kumada Catalyst-Transfer Polycondensation (KCTP): Preparation and Structuring of Poly(3-hexylthiophene)-Based Graft Copolymer Brushes

Natalya Khanduyeva, Volodymyr Senkovskyy, Tetyana Beryozkina, Marta Horecha, more

Journal of the American Chemical Society > 2009 > 131 > 1 > 153 - 161

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Kumada Catalyst-Transfer Polycondensation of Thiophene-Based Oligomers: Robustness of a Chain-Growth Mechanism

Tetyana Beryozkina, Volodymyr Senkovskyy, Elisabeth Kaul, Anton Kiriy

Macromolecules > 2008 > 41 > 21 > 7817 - 7823

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Grafting of Poly(3-hexylthiophene) from Poly(4-bromostyrene) Films by Kumada Catalyst-Transfer Polycondensation: Revealing of the Composite Films Structure

Natalya Khanduyeva, Volodymyr Senkovskyy, Tetyana Beryozkina, Vera Bocharova, more

Macromolecules > 2008 > 41 > 20 > 7383 - 7389

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Diversity Oriented Microwave-Assisted Synthesis of (−)-Steganacin Aza-Analogues

Nuria Mont, Vaibhav Pravinchandra Mehta, Prasad Appukkuttan, Tetyana Beryozkina, more

The Journal of Organic Chemistry > 2008 > 73 > 19 > 7509 - 7516

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5,7-Substituted thiazolo[2,3-a]pyrimidines: Synthesis, stereochemistry and crystal structure

Fedor Yaremenko, Tetyana Beryozkina, Alexander Khvat, Irina Svidlo, more

Journal of Molecular Structure > 2008 > 874 > 1-3 > 57-63

Reaction of 2-aminothiazoline (1) with α,β-unsaturated carbonyl compounds 2 under mild conditions (acetone, room temperature) gives two diastereomers 5-R-7-hydroxy-5H-tetrahydrothiazolo[2,3-a]pyrimidines 3. According to ¹ H NMR, major isomers of 3 have axial OH-groups whereas minor isomers have equatorial OH-groups. The X-ray investigation of compound 3i reveals only A type diastereomer in...