Publications by authors named "Tolmachev A"

The chemoselectivity of halo(het)arene sulfonyl halide aminations is studied thoroughly under parallel synthesis conditions, and the scope and limitations of the method are established. It is shown that SAr-reactive sulfonyl halides typically undergo sulfonamide synthesis during the first step; the second amination is also possible provided that the SAr-active center is sufficiently reactive. On the contrary, sulfonyl fluorides bearing an arylating moiety undergo selective transformation at the latter reactive center under proper control.

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Chemoselective transformations of functionalized sulfonyl fluorides and chlorides are surveyed comprehensively. It is shown that sulfonyl fluorides provide an excellent selectivity control in their reactions. Thus, numerous conditions are tolerated by the SO F group - from amide and ester formation to directed ortho-lithiation and transition-metal-catalyzed cross-couplings.

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Article Synopsis
  • The study focuses on modifying the surface of biodegradable Mg alloys by creating porous diatomite coatings using micro-arc oxidation at voltages between 350-500 V.
  • The addition of ZrO microparticles to these coatings was investigated for its impact on their structure and properties.
  • Results showed that while the coatings were mainly composed of small pores (<1 μm), higher voltages increased larger pores (5-10 μm), and the addition of ZrO significantly improved adhesive strength by 30% and enhanced corrosion resistance dramatically.
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Objective: Evaluation of the safety and effectiveness of thrombolytic therapy (TLT) with the drug Revelisa (alteplase) in patients with ischemic stroke (AI) in real clinical practice.

Material And Methods: An open prospective multicenter non-interventional register study was conducted, which included 550 patients with AI - 259 (47.1%) women and 291 (52.

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The unprovoked Russian invasion has created considerable challenges for Ukrainian science. In this article, we discuss actions needed to support and rebuild Ukrainian science and educational systems. The proposed actions take into account past Ukrainian scientific achievements including developments in organic chemistry.

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Ukrainian companies occupy an important niche in the global drug discovery process; however, before the Russian invasion, the role of Ukraine was not obvious. The biggest Ukrainian fine chemical supplier, Enamine Ltd, had to stop operation for more than a month, which significantly affected various early-stage drug discovery projects. The role of Enamine in drug discovery and the company's past and future in the context of the Russian invasion are described in this Viewpoint.

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A convenient "green" stereoretentive approach to -enriched secondary sulfonamides bearing an asymmetric center at the α position to the sulfur atom is described. The method relies on the electrophilic amination of the corresponding stereochemically pure sulfinates with -alkylhydroxylamine sulfonic acids (in turn easily prepared from -alkylhydroxylamine and HSOCl). It is shown that the efficiency of the approach is governed mainly by steric factors; its tolerance to several functional groups (e.

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A general approach to a new generation of spirocyclic molecules - oxa-spirocycles - was developed. The key synthetic step was iodocyclization. More than 150 oxa-spirocyclic compounds were prepared.

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Article Synopsis
  • - Species rely on environmental cues, like degree-days, to time their phenological events and exhibit varying responses based on their location and the season.
  • - The study analyzed data from 91 taxa across 472 sites in the former Soviet Union, finding that spring phenological events advance more consistently with temperature cues (cogradient variation), while autumn events are less responsive (countergradient variation).
  • - Despite some local adaptations, phenological events generally do not keep pace with environmental cues, particularly lagging further in earlier years, suggesting differing impacts of climate change on spring and autumn species responses.
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Structural restriction of the sulfonamide bond was used to design sultams with abnormal geometric parameters. Based on analysis of tertiary aliphatic sulfonamides published in the Cambridge crystallographic database, Paquette's sultams (i.e.

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We present an extensive, large-scale, long-term and multitaxon database on phenological and climatic variation, involving 506,186 observation dates acquired in 471 localities in Russian Federation, Ukraine, Uzbekistan, Belarus and Kyrgyzstan. The data cover the period 1890-2018, with 96% of the data being from 1960 onwards. The database is rich in plants, birds and climatic events, but also includes insects, amphibians, reptiles and fungi.

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Diverse trifluoromethyl-substituted compounds were synthesized by deoxofluorination of cinnamic and (hetero)aromatic carboxylic acids with sulfur tetrafluoride. The obtained products were used as starting materials in the preparation of novel fluorinated amino acids, anilines, and aliphatic amines - valuable building blocks for medicinal chemistry and agrochemistry.

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Derivatives of Brooker's merocyanine (BM) have been investigated, which possess different donors and acceptors and therefore vary their donor-acceptor strength S. The 00 energies have been extracted from the spectra and compared. Under basic conditions, where the neutral (merocyanine) form is present, the absorption energies for all compounds are similar, whereas there is a large difference for acidic conditions where the cationic (cyanine) form is present.

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Two novel solid reagents-1-sulfonimidoyl- and 1-sulfamimidoyl-3-methylimidazolium derivatives-for the synthesis of sulfonimidamides and imidosulfuric diamides, respectively, were developed. It is shown that these reagents are very effective in substitution reactions with various N- and O-nucleophiles; therefore, they significantly extend the accessibility to the chemical space covered by organosulfur(VI) compounds with S=N bonds. In addition, previously unknown imidosulfuric diamides with free imino nitrogen groups were prepared, and their physical and chemical properties were characterized (including molecular geometry, pK , Log P, microsomal stability, and reactivity towards typical electrophiles).

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Despite intense interest in expanding chemical space, libraries containing hundreds-of-millions to billions of diverse molecules have remained inaccessible. Here we investigate structure-based docking of 170 million make-on-demand compounds from 130 well-characterized reactions. The resulting library is diverse, representing over 10.

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A practical synthesis of 2,4-methanopyrrolidines was elaborated. The key synthetic step was an intramolecular photochemical [2 + 2]-cycloaddition of an acrylic acid derivative in flow. In spite of a higher molecular weight, 2,4-methanopyrrolidines were shown to have higher solubility in water and lower lipophilicity than pyrrolidines, important characteristics of bioactive molecules in drug design.

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The results of the study on reactions of halogenoximes bearing (protected) functional groups or fluorinated substituents with various phosphorus-containing dipolarophiles are described. To control the regioselectivity of the reaction, vinylphosphonates bearing a leaving group (i.e.

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Cyclic saturated aminosulfonyl fluorides were synthesized as their HCl salts. The compounds were found to be stable upon storage and could be used for the protecting-group-free synthesis of sulfonamides. In the presence of the -SO F group, the nitrogen atom could be modified by means of acylation, arylation, or reductive amination to give products that have high potential for the synthesis of bioactive compounds.

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A one-step synthesis of functionalized 3-azabicyclo[3.2.0]heptanes by [2+2]-photochemical intermolecular cycloaddition of N-benzylmaleimide to alkenes was elaborated.

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Facile synthesis of 5-fluoropyrazoles by direct fluorination of pyrazoles with N-fluorobenzenesulfonimide (NFSI) was elaborated. This approach was used to prepare the unsubstituted 5-fluoro-1 H-pyrazole, the known fungicide Penflufen, and many functionalized 5-fluoropyrazoles: building blocks for medicinal chemistry and agrochemistry.

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Difluorocyclopropane-containing building blocks for drug discovery were synthesized from the functionalized alkenes and TMSCF /NaI. Novel fluorinated acids, amines, amino acids, alcohols, ketones and sulfonyl chlorides were obtained.

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The synthesis of multifunctional spirocycles was achieved from common cyclic carboxylic acids (cyclobutane carboxylate, cyclopentane carboxylate, l-proline, etc.). The whole sequence included only two chemical steps-synthesis of azetidinones, and reduction into azetidines.

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We provide the initial performance evaluation of a 21 Tesla Fourier transform ion cyclotron resonance mass spectrometer operating at the Environmental Molecular Sciences Laboratory at the Pacific Northwest National Laboratory. The spectrometer constructed for the 21T system employs a commercial dual linear ion trap mass spectrometer coupled to a FTICR spectrometer designed and built in-house. Performance gains from moving to higher magnetic field strength are exemplified by the measurement of peptide isotopic fine structure, complex natural organic matter mixtures, and large proteins.

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