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Three-step assembly of 4-aminotetrahydropyran-2-ones from isoxazoline-2-oxides
RSC advances. 2014. Vol. 4. P. 12467-12475.
Naumova A., Mikhaylov A. A., Khomutova Y., Novikov R., Arkhipov D., Korlyukov A., Ioffe S.
Tetrahydropyran-2-ones with a 4-amino function connected to a tertiary carbon atom – a widely naturally occurring fragment – are constructed by a three step protocol from easily available isoxazoline 2-oxides. In the first stage, the carbon skeleton of the target product is formed upon a C,C-coupling of a silyl ketene acetal with a nitronate function, under silyl triflate catalysis. The key step of the assembly consists of the oxidative cleavage of an endocyclic N–O bond of intermediate cyclic nitroso acetals with mCPBA, accompanied with lactone ring closure, and gives rise to β-nitro-δ-lactones in 63–85% yields. The latter are reduced with amalgamated aluminium, to furnish the target scaffold.
Naumova A., Mikhaylov A. A., Struchkova M. et al., European Journal of Organic Chemistry 2012 Vol. 2012 No. 11 P. 2219-2224
A new procedure for the synthesis of functionalized nitro compounds from six‐membered cyclic nitronates by using the umpolung reactivity of aliphatic nitro compounds has been investigated. The reaction scheme is appropriate for the synthesis of both syn and anti isomers. ...
Added: September 30, 2020
Mikhaylov A. A., Zhmurov P., Naumova A. et al., Mendeleev Communications 2015 Vol. 25 No. 6 P. 449-451
SnCl4-promoted [4 + 2] cycloaddition of β-nitrostyrenes to 4-methylidene-1,3-dioxolane provides stereoselective synthesis of spirocyclic nitronates. 2-Nitrovinyl benzoate under the same conditions produces δ-substituted nitrodiene as a single E,E-isomer. ...
Added: September 30, 2020
Ilyushchenko M., Salikov R., Litvinenko V. et al., Journal of Organic Chemistry 2023 Vol. 88 No. 9 P. 5661-5670
An approach to the synthesis of seven-membered systems via the chain elongation of nucleophilic propenes and subsequent 8π-electrocyclization is proposed. The cascade reaction yields either cycloheptadienes or bicycloheptenes, and the latter are formed via a 6π-electrocyclization of intermediate cycloheptadienyl anion which was proved to be reversible in a basic medium. The electrocyclic nature of the ...
Added: October 18, 2023
Mikhaylov A. A., Dilman A., Novikov R. et al., Tetrahedron Letters 2016 Vol. 57 No. 1 P. 11-14
The first successful synthesis of 1H-2,3-benzoxazine 3-oxides has been described. The efficiency of the approach is provided by the C–C-coupling of 2-(2-bromoaryl)cyclopropane-1,1-dicarboxylates with primary nitroalkanes catalyzed by Pd(dba)2/JohnPhos system followed by in situ recyclization of the intermediates. Several representative transformations allowing selective modification of the nitronate as well as malonate functionalities in the resulting compounds are demonstrated. ...
Added: September 30, 2020
Mikhaylov A. A., Dilman A., Kunetsky R. et al., Tetrahedron Letters 2010 Vol. 51 No. 7 P. 1038-1040
A series of 3-halomethyl-5,6-dihydro-1,2-oxazine N-oxides (halogen = Cl, Br, I) is prepared from 4-phenyl-3,6,6-trimethyl-5,6-dihydro-4H-oxazine N-oxide by means of a silylation/halogenation sequence. The obtained halogenated N-oxides undergo reactions typical of cyclic six-membered nitronates including 1,3-dipolar cycloaddition, addition of nucleophiles, and substitution of the halogen by C-, S-, and N-nucleophiles. ...
Added: September 30, 2020
Mikhaylov A. A., Dilman A., Khomutova Y. et al., European Journal of Organic Chemistry 2013 Vol. 2013 No. 25 P. 5670-5677
N‐Silylamines add to six‐membered nitronates with high diastereoselectivity. The reaction follows an original mechanism in which thermodynamic control plays the key role. ...
Added: September 30, 2020
Mikhaylov A. A., Khomutova Y., Arkhipov D. et al., Mendeleev Communications 2014 Vol. 24 No. 6 P. 374-376
Six-membered cyclic nitronates smoothly react with trialkylsilyl cyanide/ButMe2SiOTf or tert-butyl isocyanide/ButMe2SiOTf systems to afford 2-trialkylsilyloxy-3-cyanotetrahydro-[4H]-1,2-oxazines or δ-oxo-α-trialkylsilyloximinonitriles depending on the ring-substitution pattern. ...
Added: September 30, 2020
Arutyunov V., Nikitin A., Strekova L. et al., Catalysis Today 2021 No. 379 P. 23-27
Low energy density in agricultural or biotechnological raw materials dictates the need for their local processing. Small-scale agricultural products or waste processing plants can`t profitably use technologies common in large-scale petrochemistry, including the complex and expensive process of steam reforming of biogas into syngas for its subsequent conversion to liquid fuel. The work suggests using ...
Added: October 3, 2022
Mikhaylov A. A., Dilman A., Struchkova M. et al., Tetrahedron 2011 Vol. 67 No. 25 P. 4584-4594
A method for the introduction of a halogen atom into the methyl group attached to the C-3 atom of five- and six-membered cyclic nitronates (isoxazoline N-oxides and oxazine N-oxides, respectively) has been studied. The process involves silylation of starting 3-methyl-substituted cyclic nitronates followed by halogenation of the resulting N-(silyloxy)enamines. While five- and six-membered cyclic enamines behave similarly toward ...
Added: September 30, 2020
Cha J., Lee E., Dmitry V. Yandulov, Inorganic Chemistry 2022 Vol. 61 No. 37 P. 14544-14552
Molecular oxygen (O2) remains to be an ideal yet underutilized feedstock for the oxidative transformation of organic substrates and renewable energy systems such as fuel cells. Palladium (Pd) has shown particular promise in enabling these applications. The present study describes a Pd-mediated O2 reduction to water via C–H activation of 9,10-dihydroanthracene (DHA) by a Pd(II) ...
Added: October 24, 2022
Savchenko V. I., Nikitin A. V., Zimin Y. S. et al., Chemical Engineering Research and Design 2021 Vol. 175 P. 250-258
Non-catalytic partial oxidation of methane in matrix reformers offers the possibility of producing hydrogen directly at sites of its consumption, in particular from local bioresources and non-traditional fossil hydrocarbons. The kinetics simulation of the process shows that it proceeds in two stages. In the flame zone, in the presence of oxygen, along with CO, H2, ...
Added: October 3, 2022
I. V. Sedov, Arutyunov V. S., Tsvetkov M. V. et al., Eurasian Chemico-Technological Journal 2022 Vol. 24 No. 2 P. 157-163
The possibility of using coalbed methane to produce methanol is assessed. Methanol can be obtained from methane both by direct partial oxidation and from synthesis gas formed through the oxidative conversion of methane. Thermodynamic analysis of coalbed methane conversion was carried out to determine the conditions for obtaining synthesis gas with the ratio [H2 ]/[CO] = ...
Added: October 7, 2022
Mikhaylov A. A., Novikov R., Khomutova Y. et al., Synlett 2014 Vol. 25 No. 16 P. 2275-2280
1,1-Cyclopropane diesters with donor substituents undergo formal [3+3] cycloaddition with various silyl nitronates under Yb(OTf)3 catalysis in the presence of a proton scavenger to give target N-silyloxy tetrahydro-1,2-oxazines in 56–98% yield. The reasons determining the reaction diastereoselectivity are discussed. The resulting tetrahydro-1,2-oxazines are transformed into pyrroline-N-oxides via a novel TfOH-promoted silanol elimination reaction. ...
Added: September 30, 2020
Ioffe S., Khoroshutina Y., Smirnov V. et al., Kinetics and Catalysis 2018 Vol. 59 P. 691-700
A new four-stage algorithm for the reactivity umpolung of aliphatic nitro compounds has been proposed and experimentally confirmed. Bis(trialkylsilyloxy)iminium cations, which are key intermediates in the new scheme, have been qualitatively and quantitatively determined by the method of double nuclear magnetic resonance. Their thermodynamic parameters have been determined. The kinetics of coupling of these cations ...
Added: September 29, 2020
Abramov V., Abramova A., Bayazitov V. et al., Processes 2022 Vol. 10 No. 10 Article 2063
Although water contamination with drug residues is a threat to public health, there are currently barely any effective methods of purifying water from pharmaceutical substances. In this study, continuous-flow sonoplasma treatment was used for the complete degradation of tetracycline and ciprofloxacin in polluted municipal water. The addition of CeO2 nanoparticles as catalysts significantly increased the degradation ...
Added: October 23, 2022
Faraonov M., Romanenko N., Mikhailenko M. et al., New Journal of Chemistry 2021 Vol. 45 P. 13599-13607
Reduction of organic dye trans-perinone (its abbreviation is perinone) in different experimental conditions allows us to obtain and characterize radical anion {cryptand(K+)}[perinone˙−] (1) and dianion {PPN+}2[perinone2−]·2C6H4Cl2 (2) salts of this dye. The salts have layered structures. Perinone˙− radical anions form π–π stacked dimers in 1 with an effective interaction between them, whereas perinone2− dianions are ...
Added: October 21, 2022
Astakhov A., Chernenko A., Kutyrev V. et al., Inorganic Chemistry Frontiers 2023 Vol. 10 No. 1 P. 218-239
C-Amino-1,2,4-triazoles are challenging polynitrogen substrates for metal-catalyzed arylation due to their multidentate character, enhanced coordinating ability and decreased nucleophilicity of the amino group. In the present study, the Buchwald–Hartwig cross-coupling of diverse 3(5)-amino-1,2,4-triazoles with aryl chlorides and bromides delivering (hetero)arylamino-1,2,4-triazoles in good-to-excellent yields under Pd/NHC catalysis was developed. The use of Pd complexes with bulky ...
Added: February 14, 2024
Nikolaev S. A., Tsodikov M. V., A. V. Chistyakov et al., Catalysis Today 2021 Vol. 379 P. 50-61
PdCu/Al2O3 (Pd = 0.1 wt.%, Cu = 0.1 wt.%) catalyst and its monometallic analogues (Pd/Al2O3 and Cu/Al2O3) were prepared by combination of deposition-precipitation and impregnation methods. The structure of the catalysts was studied by means of XRD, TEM, EDS, TPD-NH3, and DRIFTS. In a standard run (275 ○C, 5 h), Cu/Al2O3 converts 11 % of ethanol to α-alcohols with ...
Added: November 11, 2023
Svitanko I., Pivina T. S., Khakimov D. V., Journal of Molecular Modeling 2024 Vol. 30 Article 93
Using quantum chemistry and atom–atom potential methods, the molecular and crystal structures of cubane 1 and all types of unsubstituted azacubanes 2–22 were calculated. Alternative possible polymorphs of cubane 1 have been proposed. The thermochemical properties of azacubanes in the gas and solid phases were assessed. Thermodynamic aspects of stability are considered, and a significant ...
Added: March 13, 2024
Tatiana L. Kulova, Skundin A., Gavrilin I. M. et al., Batteries 2022 Vol. 8 No. 8 Article 98
Nanostructure composites Ge-Co-P with brutto-composition CoGe2P0.1, or CoGe2@GeP were manufactured via electrolysis of aqueous electrolyte. Such composites are able to reversible insertion of lithium and sodium with specific capacities up to 855 and 425 mAh/g, respectively. The main advantage of the composites consists in their excellent cycleability. ...
Added: November 25, 2022
Shirokova V., Ikonnikova V., Solyev P. et al., Synthesis 2021 Vol. 53 No. 24 P. 4689-4699
Directly accessible 8-substituted tetrahydroquinolines undergo 1,5-hydride shift-triggered cyclization to provide hardly accessible julolidine derivatives in 20-98% yield under scandium (III) triflate catalysis. The scope of the reaction, several follow-up transformations and a remarkable side-process discovered during the conditions optimization are highlighted. ...
Added: July 29, 2021
Андрюшечкин Б. В., Eltsov K., Pavlova T. et al., Journal of Chemical Physics 2018 Vol. 148 No. 24 Article 244702
The adsorption of O-2 on Ag(111) between 300 and 500 K has been studied with temperature-programmed desorption (TPD) and scanning tunneling microscopy (STM). At the first stage of adsorption, the disordered local oxide phase (commonly looking in STM as an array of black spots) is formed on the surface irrespective of the substrate temperature. The maximum concentration of black spots was found to be approximate to 0.11 ML, which corresponds to an oxygen coverage of approximate to 0.66 ML. Taking into account that the nucleation of the Ag(111)-p(4 x 4)-O phase starts after the saturation of the disordered phase, one ...
Added: October 25, 2021
Budkov Y., Kolesnikov A. L., Polymer Science - Series C 2018 Vol. 60 No. Supplement 1 P. 148-159
Theoretical models of the conformational behavior of flexible polymer chains in mixed solvents enunciated in the world literature during the last decade are critically reviewed. Models describing different mechanisms of coil-to-globule transitions in a good solvent induced by cosolvent addition are highlighted. Special attention is given to the analysis of theoretical approaches to describing the ...
Added: November 30, 2018
Yurova P., Малахова В. Р., Gerasimova E. V. et al., Polymers 2021 Vol. 13 No. 15 P. 2513
Low chemical durability of proton exchange membranes is one the main factors limiting their lifetime in fuel cells. Ceria nanoparticles are the most common free radical scavengers. In this work, hybrid membranes based on Nafion-117 membrane and sulfonic or phosphoric acid functionalized ceria synthesized from various precursors were prepared by the in situ method for ...
Added: February 3, 2022