排序方式: 共有49条查询结果,搜索用时 15 毫秒
1.
Strunskaya E. I. Yanilkin V. V. Bredikhina Z. A. Nastapova N. V. Morozov V. I. Maksimyuk N. I. Sharafutdinova D. R. Bredikhin A. A. 《Russian Journal of General Chemistry》2003,73(5):806-815
The electron-acceptor nitrogen and sulfur atoms in 3,4-disubstituted 1,2,5-thiadiazoles are responsible for much decreased reduction potentials and much increased oxidation potentials of these compounds compared with the corresponding carbocyclic derivatives. The thiadiazole ring is resistant to oxidation, and the reversible electron transfer gives rise to fairly stable radical cations. Reductive stability of the heterocycle depends on the nature of its substituents and on the medium: When nucleofuge substituents are present, two-electron transfer in aprotic media results in heteroring opening with iminonitrile formation, whereas in the presence of two readily leaving groups, the electron transfer induces cleavage of the complete heteroring into inorganic anions. 相似文献
2.
Bredikhin A. A. Lazarev S. N. Bredikhina Z. A. Savel"ev D. V. Vandyukova I. I. Gubaidullin A. T. Litvinov I. A. 《Russian Chemical Bulletin》2003,52(4):846-852
Crystalline specimens of homochiral and racemic glycidyl p-toluenesulfonate were studied by IR spectroscopy, differential scanning calorimetry, and X-ray diffraction analysis. The melting phase diagram of glycidyl p-toluenesulfonate was constructed. The stacking effect in the crystals of the racemic sulfonate is responsible for a more dense molecular packing, with the result that a heterochiral type of crystallization becomes more favorable. 相似文献
3.
Bredikhina Z. A. Pashagin A. V. Savel"ev D. V. Bredikhin A. A. 《Russian Chemical Bulletin》2001,50(3):436-439
Nonracemic -blockers, viz., (S)-propranolol and (S)-timolol, were prepared from (S)-glycidol in three steps consisting in the reaction with SOCl2 followed by the reaction of the resulting (4S)-4-chloromethyl-2-oxo-1,3,2-dioxathiolanes with the corresponding phenol and the final cleavage of (4R)-aryloxymethyl sulfites under the action of amines in DMF. 相似文献
4.
Alexander A. Bredikhin Zemfira A. Bredikhina Alexey V. Kurenkov Dmitry B. Krivolapov 《Tetrahedron: Asymmetry》2017,28(3):442-446
Racemic 3-(4-indolyloxy)-1,2-propanediol 2 has been effectively resolved into (S)- and (R)-enantiomers by a preferential crystallization procedure. Non-racemic (S)-2 was converted into (S)-4-(2,3-epoxypropoxy)-1H-indole (S)-4 via a Mitsunobu reaction and then into (S)-pindolol (S)-1. The crystalline (S)-1 was studied by single crystal X-ray diffraction. A large number of symmetry independent molecules (Z′ = 6) led to a weakening of the system of strong intermolecular hydrogen bonds, which combined with a loose packing (PI = 64.6%), may be the cause of the abnormally low melting point of (S)-1 as compared with rac-1. 相似文献
5.
D. R. Sharafutdinova R. R. Fayzullin O. V. Bazanova Z. A. Bredikhina I. H. Rizvanov A. A. Bredikhin 《Journal of Analytical Chemistry》2013,68(14):1178-1182
Mixtures of unsubstituted 15-crown-5 and its analogues containing ortho- and para-methoxyphenoxymethyl substituents with sodium salts were investigated by matrix assisted laser desorption/ionization (MALDI) mass spectrometry. Peaks of cationized molecules [M+Na]+ and cluster ions [2M+2Na+An]+, where M is the crown ether molecule and An is monobasic acid anion, were observed in the mass spectra. It was shown that an increase of the shielding degree of the sodium cation in complexes with crown ethers, i.e., the lariat effect, led to a significant decrease in the intensity of peaks of the cluster ions. 相似文献
6.
The reactions of 4-chloromethyl-1,3,2-dioxathiolane 2-oxides with PhONa in EtOH are accompanied by ring opening under the
action of the ethoxide ion rather than leading to a rearrangement of the starting molecule as has been assumed previously.
Under conditions precluding competition with other nucleophiles, the phenoxide anion smoothly replaces the chlorine atom in
chloromethyl-substituted cyclic sulfites.
Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1774–1777, October, 2000. 相似文献
7.
8.
Bredikhin A. A. Pashagin A. V. Strunskaya E. I. Gubaydullin A. T. Litvinov I. A. Bredikhina Z. A. 《Russian Chemical Bulletin》1999,48(11):2086-2090
2,3-Epoxy alcohols (glycidols) react with carboxylic acid dichlorides to form cyclic esters of 3-chloro-1,2-diols. The reaction
proceeds with complete retention of the configuration of the C(2) atom of the initial glycidol and with predominant (but not
complete) inversion of the configuration of the C(3) atom in the final heterocycle.
Translated fromIzvestiya Akademii Nuak. Seriya Khimicheskaya, No. 11, pp. 2110–2114, November, 1999. 相似文献
9.
D. V. Zakharychev S. N. Lazarev Z. A. Bredikhina A. A. Bredikhin 《Russian Chemical Bulletin》2006,55(2):230-237
Specific features of melting of crystalline samples of 3-(2-R-phenoxy)propane-1,2-diols with different enantiomeric compositions
were studied by differential scanning calorimetry. The melting points and enthalpies of melting for the racemate and individual
stereoisomers were determined. Binary phase diagrams were constructed. The entropy of mixing of individual enantiomers in
the liquid phase and the free energy of formation of the racemic compound were calculated. The thermochemical data indicate
that the racemates are formed upon the crystallization of phenoxy-and 2-fluorophenoxy-containing compounds, while crystallization
of the chloro-, bromo-, and iodo-substituted analogs would form racemic conglomerates.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 225—232, February, 2006. 相似文献
10.
Bredikhina Z. A. Kurenkov A. V. Bredikhin A. A. 《Russian Journal of Organic Chemistry》2019,55(6):837-844
Russian Journal of Organic Chemistry - Six regioisomeric nonracemic dimethylphenyl glycerol ethers were synthesized by asymmetric dihydroxylation of the corresponding allyl dimethylphenyl ethers.... 相似文献