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51.
G. N. Balandina G. I. Lavrenova L. D. Uzhinova E. A. Chekhovskikh N. A. Platé V. M. Stepanov 《Chemistry of Natural Compounds》1986,22(2):200-203
A new polymeric sorbent for proteinases has been synthesized by the radical copolymerization of N-vinylpyrrolidone, bis-N-acryloylgramicidin C, and N,N-methylenebisacrylamide. Biospecific chromatography on the new sorbent has enabled an industrial preparation of procine pepsin to be purified by a factor of 2.5. With the aid of the new sorbent, a carboxylic proteinase has been isolated from the industrial preparation Tsellolignorin with a 15-fold purification factor.M. V. Lomonosov State University. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 215–218, March–April, 1986. 相似文献
52.
V. P. Borovikova N. N. Tarasova G. N. Lavrenova V. M. Stepanov 《Chemistry of Natural Compounds》1979,15(2):161-168
Summary 1. The chromatography of the carboxylic proteinases porcine pepsin, aspergillopepsin A, and chymosin on the hydrophobic sorbent Sepharose 4B-DNP-hexamethylenediamine has been studied. It has been shown that the nature of the binding of the proteinases with the sorbent depends on the pH.2. A shortening of the length of the carbohydrate chain of the ligand by four methylene units substantially weakens the interaction of pepsin with the sorbent.3. With chymotrypsin and pepsin as examples, the possibility has been shown of using ionic effects for separating these enzymes.M. V. Lomonosov Moscow State University. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 191–199, March–April, 1979. 相似文献
53.
Natural (+)-iridomyrmecin and its unnatural enantiomer (−)-iridomyrmecin were synthesized by intramolecular [3+2] dipolar
cycloaddition of silyl nitronates that had been generated from the nitro derivatives of (+)- and (−)-citronellenes, respectively.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1683–1687, September, 1997. 相似文献
54.
V. P. Perevalov M. A. Andreeva L. I. Baryshnenkova V. Ya. Gurvich B. I. Stepanov 《Chemistry of Heterocyclic Compounds》1990,26(2):204-208
2-Methyl-2,4,12,13H-pyrazolo[3,4-5,6]pyrimido[1,2-b]benzo[d,e]isoquinoline-4,12-dione and its 8-nitro- and 8-amino-substituted derivatives were obtained starting from 4-amino-3-carbamoyl-1-methylpyrazole and naphthalic and 4-nitronaphthalic anhydrides. The spectral properties of the synthesized compounds were studied.See [1] for Communication 8.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 237–241, February, 1990. 相似文献
55.
Indirect reduction of 1-phenylethylbromide (I) and 1-(4-isobutylphenyl)ethylchloride (II) in a carbon dioxide atmosphere containing tris(2,2-bipyridyl)nickel tetrafluoroborate (BPN) is studied. In the reactions the BPN complex exhibits properties of a one-electron mediator and catalyzes radical generation from aryl halides, which mostly undergo dimerization. Electroreduction of I and II in the presence of -cyclodextrin and BPN yields biaryls with a low enanthioselectivity (1.5%), which may indicate generation of a small amount of inclusion complexes and dimerization of intermediate radicals in the hydrophobic cavity of -cyclodextrin. 相似文献
56.
V. M. Byakov V. I. Grafutin O. V. Ilyukhina G. G. Myasishcheva F. G. Nichiporov S. V. Stepanov O. P. Stepanova Yu. V. Funtikov 《High Energy Chemistry》2004,38(6):420-424
The yields of formation of radiolytic hydrogen (H2) and orthopositronium (o-Ps) in aqueous and alcoholic acetone solutions were experimentally determined. A decrease in the o-Ps yield with an increase in the acetone concentration is much weaker than the decline in the yield of solvated electrons (e–
s) under picosecond pulse radiolysis conditions. In contrast, the decrease in the o-Ps yield is minimal in higher alcohols where the inhibiting action of acetone e–
s is most pronounced. These findings seem to contradict the conventional concepts of Ps formation via the intratrack reaction of positron recombination with a track electron (e–), which competes with the reaction of e– scavenging by dissolved acetone molecules. This contradiction can be eliminated, assuming that the scavenging of e– by acetone begins from the formation of the weakly bound transient state (CH3)2CO···e– capable of donating e– to a positron. This opens up an additional pathway for the formation of the Ps atom. 相似文献
57.
An instability criterion based on the positivity of a Lyapunov-type exponent is used to study the stability of the Euler equations governing the motion of an inviscid incompressible fluid. It is proved that any flow with exponential stretching of the fluid particles is unstable. In the case of an arbitrary axisymmetric steady integrable flow, a sufficient condition for instability is exhibited in terms of the curvature and the geodesic torsion of a stream line and the helicity of the flow. 相似文献
58.
I. I. Popov N. S. Vashurin S. E. Putilin S. A. Stepanov V. T. Sidorova N. I. Sushentsov 《Bulletin of the Russian Academy of Sciences: Physics》2014,78(2):152-155
A femtosecond stimulated photon echo is detected for the first time in thin semiconductor films with thicknesses of 100, 800, and 2400 nm. It is established that relaxation time T 1 varies with ZnO film thickness, taking values of 0.96, 2.96, and 4.312 ps at thicknesses of 2400, 800, and 100 nm, respectively. For ZnO/Si+/Si? trilayer films, the relaxation time is T 1 = 12.73 ps. 相似文献
59.
V. N. Andreev V. A. Grinberg A. G. Dedov A. S. Loktev N. A. Mayorova I. I. Moiseev A. A. Stepanov 《Russian Journal of Electrochemistry》2013,49(10):996-1000
The electrooxidation of a (~3: 1) mixture of trifluoroacetic and 10-undecylenic acids in MeCN with an aqueous KOH addition on different anodic catalysts was studied. The oxidation of trifluoroacetate ions that forms trifluoromethyl radicals is the key stage of the process, while 10-undecylenic acid seems to be merely an acceptor of the electrogenerated radicals, i.e., shows the chemical properties characteristic of olefins. The galvanostatic electrolysis of trifluoroacetic and 10-undecylenic acids led to a mixture of the products of trifluoromethylation of the latter and the products of coupling of the formed radical species. According to a qualitative estimation, the total yield of these products was 74%. 相似文献
60.
A. A. Stepanov N. D. Lenenko A. S. Golub’ V. S. Pervov 《Russian Journal of Electrochemistry》2013,49(1):86-90
Intercalated group IVB-VIB metal disulfides and diselenides MX2 (M = Ti, Zr, Nb, Mo) can be obtained by electrochemical reduction of the corresponding MX2 in the presence of tetraalkylammonium salt. An original approach was used, which allowed effective reduction of these insoluble substances in the form of powders suspended in an organic solvent using the standard electrolysis technique in solutions in a one-space electrolyzer with a soluble anode. Using electron transfer mediators in the process afforded intercalated compounds with yields of 60–100%. 相似文献