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21.
Vladimir A. Alfonsov Alexander A. Bredikhin Zemfira A. Bredikhina Rimma M. Eliseenkova Olga N. Kataeva Igor A. Litvinov Michael A. Pudovik 《Structural chemistry》2008,19(6):873-878
The first three examples of the cocrystallization of covalent diastereomers of phosphorus compounds containing different chiral
elements (centres of chirality on carbon and phosphorus, and an axis of chirality) are reported. The phenomenon can be attributed
to the complementarity of the molecular shapes of the diastereomers. The X-ray data of all the crystals exhibit centrosymmetric
statistics regardless of their very different natures.
Dedicated to the memory of Professor Viktor Naumov (1932–2007). 相似文献
22.
Z. A. Bredikhina B. I. Buzykin Yu. P. Kitaev 《Chemistry of Heterocyclic Compounds》1991,27(4):427-433
The condensation of thiosemicarbazones with bromopyruvic acid gives thiazolylhydrazone hydrobromides, which were converted to the free bases. The question of the site of protonation was studied by PMR spectroscopy. The possibility of self-protonation in 4-carboxythiazolylhydrazone crystals is not excluded. The thiazolylhydrazones are brominated in the 5 position. Both cyclization to thiazolyltriazoles and the Chetteueya—Walker reaction are realized in the case of oxidation with lead tetraacetate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 537–543, April, 1991. 相似文献
23.
Bredikhin A. A. Bredikhina Z. A. Gubaidullin A. T. Litvinov I. A. 《Russian Journal of General Chemistry》2003,73(8):1282-1287
The stereoisomers of 5-phenoxy-1,3,2-dioxathiane 2-oxide both exist as chair conformers with an axial S = O bond. The features of conformational behavior, distinguishing this diastereomeric pair from earlier studied are explained in terms of the conformational energies of substituents in the 1,3-dioxane series. 相似文献
24.
Bredikhin A. A. Strunskaya E. I. Novikova V. G. Azancheev N. M. Sharafutdinova D. R. Bredikhina Z. A. 《Russian Chemical Bulletin》2004,53(1):213-218
The enantioselective partial hydrolysis of a number of racemic aryl glycidyl ethers in the presence of chiral Co(salen)-catalyst was studied. The enantiomeric composition of the isolated (R)-aryl glycidyl ethers was analyzed by 31P NMR using optically active substituted 2-chloro-1,3,2-dioxaphospholanes. A synthesis of -adrenoblocking agents (S)-toliprolol and (S)-moprolol based on the simultaneously obtained (S)-3-aryloxypropane-1,2-diols was proposed. 相似文献
25.
Yanilkin V. V. Bredikhina Z. A. Maksimyuk N. I. Morozov V. I. Nastapova N. V. Bredikhin A. A. 《Russian Chemical Bulletin》2002,51(1):78-84
The character of the first stage of reduction of 5-X-5-nitro-1,3-dioxanes 1—10 and 2-X-2-nitro-1,3-propanediols 11 and 12 is independent of the nature of halogen (X = Br, Cl) and substituents in position 2 of the dioxane cycle. The transfer of two electrons to a molecule of compound 1—12 is accompanied by the anionoid elimination of halogen and formation of the anion of nitronic acid. The high mobility of halogen is mainly due to the acceptor nitro group capable of further transformations in the -position to halogen. The direction of further reduction involving the electron transfer to electrochemically active groups in the aromatic fragment of the molecule is determined by the nature of these groups. Chloro-, bromo-, and iodophenyl-substituted derivatives 4, 5, and 8—10 are reduced as typical halobenzenes. In the case of nitrophenyl-substituted compounds 3 and 7, the dioxane cycle opens to form dianions of p- and m-nitrobenzaldehydes along with the reduction of the nitroso group through the stages of formation of the radical anion and radical anion of the nitroso group. The radical anions of the nitro and nitroso derivatives were identified by ESR. 相似文献
26.
New approach to cyclic sulfites and sulfates through reactions of sulfur oxychlorides with glycidols
A. A. Bredikhin A. v. Pashagin Z. A. Bredikhina S. N. Lazarev A. T. Gabaidullin I. A. Litvinov 《Russian Chemical Bulletin》2000,49(9):1575-1582
Reactions of 2,3-epoxyalcohols (glycidols) with thionyl chloride or sulfuryl chloride afford cyclic sulfites or sulfates,
respectively. These reactions yield predominantly 4-chloroalkyl-1,3,2-dioxathiolane oxides. The configuration of the C(4)
atom in the latter compounds exactly corresponds to that of the C(2) atom of the parent glycidol, whereas the configuration
of the exocyclic atom is almost completely reversed with respect to that of the C(3) atom of the precursor.
Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1586–1593, September, 2000. 相似文献
27.
Bredikhina Z. A. Novikova V. G. Azancheev N. M. Bredikhin A. A. 《Russian Journal of General Chemistry》2002,72(8):1207-1214
The regioisomeric composition of the adducts of unsymmetrical oxiranes with achiral and chiral phosphorochloridites was studied. Factors allowing enantiomeric assessment of chiral oxiranes with the aid of chiral derivatizing organophosphorus reagents were revealed. 相似文献
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30.
N. V. Nastapova V. V. Yanilkin R. M. Eliseenkova V. I. Morozov E. I. Strunskaya Z. A. Bredikhina A. A. Bredikhin B. I. Buzykin 《Russian Journal of Electrochemistry》2003,39(11):1166-1180
Electrochemical reduction of phthalazines and 1,2,5-thiadiazoles containing nucleofugaceous groups at the carbon -atoms are studied in aprotic and proton-donating media. Heteroatoms, substituents, and media are found to affect potentials and reaction path for the electroreduction. The factors determining the reductive opening of heterocycles are revealed. In diazines the heterocycle opening in annelated systems is induced by the electron transfer, provided there exist (a) a heteroatom–heteroatom bond and (b) an easily splitting-off group at the carbon -atom, whose nucleofugacity is comparable with or exceeds that of the chloride ion. Stability of the 1,2,5-thiadiazole cycle toward its reduction is determined by the substituent and the medium nature. On adding a nucleofugaceous group to the molecule, the transfer of two electrons in an aprotic medium results in the heterocycle opening with the formation of iminonitrile; when two easily splitting-off groups are present, the electron transfer makes the cycle decompose into inorganic anions. 相似文献