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991.
A. Yu. Korontzevich V. N. Vorobiev A. T. Serodzhev R. Kh. Karimov K. Kh. Razikov 《Reaction Kinetics and Catalysis Letters》1986,30(2):283-288
Diffuse reflectance spectroscopy and X-ray phase analysis studies of Ag/–Al2O3 catalysts have revealed that in thermal decomposition of supported silver nitrate part of Ag+ ions are oxidized to Ag2+ and Ag3+ ions localized in the carrier lattice, which preserve up to temperatures above 900 °C.
Ag/–Al2O3 . , Ag+ Ag2+ Ag3+, 900 °C.相似文献
992.
Summary 1. Qualitative and quantitative compositions of the main alkaloids in five development phases of theGoebelia pachycarpa C. A. Mey. have been determined.2. The radioactivities of the alkaloids isolated after feeding the plant with assumed precursors -[2-14C] lysine and [1,5-14C] cadaverine — show that vigorous synthesis of alkaloids takes place in the flowering and budding periods.3. The results of an investigation of the oxidation products and of the alkaloids introduced and isolated after the feeding of plants with labelled matrine and labelled sophocarpine show that the alkaloids undergo interconversion without intramolecular changes.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh, Soedinenii, No. 4, pp. 549–552, July–August, 1977. 相似文献
993.
V. P. Zakharov Kh. A. Aslanov A. I. Ishbaev A. S. Sadykov B. A. Yankovskii 《Chemistry of Natural Compounds》1976,10(4):474-476
Summary 1. The optimum conditions for the extraction of the high-boiling alkaloids from technical anabasine sulfate by dilution with water and at various pH values of the medium have been established.2. A method for removing anabasine and lupinine from a mixture of the high-boiling alkaloids ofAnabasis aphylla has been developed which is based on the formation of the carbonates of the strong bases.V. I. Lenin Tashkent State University. Dzerzhinskii Chimkent Pharmaceutical Chemicals Factory. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 468–472, July–August, 1974. 相似文献
994.
P. W. Naik P. S. Dhami S. K. Misra U. Jambunathan J. N. Mathur 《Journal of Radioanalytical and Nuclear Chemistry》2003,257(2):327-332
Silica-gel has been used as an inert support for the extraction chromatographic separation of actinides and lanthanides from HNO3 and synthetic high level waste (HLW) solutions. Silica-gel was impregnated with tri-butyl phosphate (TBP), to yield STBP; 2-ethylhexyl phosphonic acid, mono 2-ethylhexyl ester (KSM-17, equivalent to PC-88A), SKSM; octyl(phenyl)-N,N-diisobutyl carbamoylmethylphosphine oxide (CMPO), SCMPO; and trialkylphosphine oxide (Cyanex-923), SCYN and sorption of Pu(IV), Am(III) and Eu(III) from HNO3 solutions was studied batchwise. Several parameters, like time of equilibration, HNO3 and Pu(IV) concentrations were varied. The uptake of Pu(IV) from 3.0M HNO3 followed the order SCMPO>SCYN>SKSM>STBP. With increasing HNO3 concentration, D
Pu increased up to 3.0M of HNO3 for STBP, SKSM and SCMPO and then decreased. In the case of Am and Eu with SCMPO, the D values initially increased between 0.5 to 1.0M of HNO3, remained constant up to 5.0M and then slightly decreased at 7.5M. Also, the effects of NaNO3, Nd(III) and U(VI) concentrations on the uptake of Am(III) from HNO3 solutions were evaluated. With increasing NaNO3 concentration up to 3.0M, D
Am remained almost constant while it was observed that it decreases drastically by adding Nd(III) or U(VI). The uptake of Pu and Am from synthetic pressurized heavy water reactor high level waste (PHWR-HLW) in presence of high concentrations of uranium and after depleting the uranium content, and finally extraction chromatographic column separation of Pu and Am from U-depleted synthetic PHWR-HLW have been carried out. Using SCMPO, high sorption of Pu, Am and U was obtained from the U-depleted HLW solution. These metal ions were subsequently eluted using various reagents. The sorption results of the metal ions on silica-gel impregnated with several phosphorus based extractants have been compared. The uptake of Am, Pu and rare earths by SCMPO has been compared with those where CMPO was sorbed on Chromosorb-102, Amberchrom CG-71 and styrene divinylbenzene copolymer immobilized in porous silica particles. 相似文献
995.
Two new alkaloids nitraramidine and nitraraidine were isolated from the aerial part of Nitraria sibirica. Their structures were established using spectral data and chemical transformations. 相似文献
996.
Viktoriya V. Skripacheva Ella Kh. Kazakova Nelly A. Markarova Vladimir E. Kataev Ludmila V. Ermolaeva Wolf D. Habicher 《Journal of inclusion phenomena and macrocyclic chemistry》2002,42(1-2):77-81
The binding of different sized and shaped metal complexes [Co(His)2]ClO4(1), [Co(en)2C2O4]Cl (2) and [K18-crown-6]SCN (3)(en-ethylendiamine, His-L-histidynate-anion) with a new tetrasulfonatomethylcalix[4]resorcinarene([H8X]Na4) was investigated in neutral and alkaline aqueous media by NMR and pH-metrictitration methods and compared with those of recently studied NMe4Br (4). The resultsobtained indicate that the outer-sphere coordination of complexes 1–3 by[H8X]4- proceeds via the interaction of hydrophobic fragments of the guestswith both the negatively charged rim and the hydrophobic cavity as a -base. Thenature of binding does not change for cations 1, 2 and 4 on going from[H8X]4- in neutral to [H4X]8- in alkaline media, while the inclusionof 3 decreases on going from [H8X]4- to [H4X]8-. 相似文献
997.
L. U. Joshi M. D. Zingde B. N. Desai 《Journal of Radioanalytical and Nuclear Chemistry》1984,82(2):369-377
The sediment samples have been collected from estuarine regions of Mindola and Purna of Gujarat State. These samples are found to contain less than 3% of organic matter which scavange and carry most of the activity of226Ra, etc., to the sediment floor. The activities of226Ra are found to vary from 0.1 to 0.5 pCi/g, while210Pb activities lie in the range of 3 to 8 pCi/g. These activities find their way into the organisms present in sea water and then into fish which is finally consumed by humans. This paper gives in detail the sampling techniques, experimental procedures and the distribution of the isotopes of226Ra and210Pb in the estuarine regions and the concentration factors of226Ra in the region. 相似文献
998.
Zakharov S. V. Nuriazdanova G. Kh. Garifzyanov A. R. Galkin V. I. Cherkasov R. A. 《Russian Journal of General Chemistry》2004,74(6):873-881
-Aminophosphoryl compounds of the phosphonate, phosphine oxide, and ,-bis(phosphine oxide) series and some of their thiophosphoryl analogs were synthesized. Potentiometric measurements of the pKa of the conjugate acids revealed an insignificant effect of variation of substituents on the phosphorus, nitrogen, and -carbon atoms on the basicity of the phosphorylated amines. The latter are weak bases. Organophosphorus groups decrease the basicity of the amines by almost 5 pK
a units. The role of the hydrophobic effect and intramolecular H-bonding in the obtained substances was discussed. 相似文献
999.
The development of new and broadly applicable linker groups which are stable under a variety of reaction conditions and allow release of the desired products from the solid support under very mild conditions is of great interest in organic synthesis and combinatorial chemistry. We describe an enzyme-labile safety-catch linker which releases alcohols and amines through i) enzymatic cleavage of an amino group and ii) subsequent lactam formation. The linker group was investigated on different polymeric supports: TentaGel. PEGA, CPG-beads and the soluble polymer POE-6000. From these linker-polymer conjugates 2-methoxy-5-nitrobenzyl alcohol was released by penicillin G acylase catalysed cleavage of a phenylacetamide and attack of the liberated benzylamine on the neighbouring ester group in ortho position. The model study revealed that only in the case of soluble POE-6000 conjugate high yields for the cleavage could be achieved. In the case of the other solid supports the enzyme does not have access to the interior of the polymer matrix. The application of the POE-6000 linker conjugate was investigated for various esters in Pd0-catalysed Heck-, Suzuki- and Sonogashira reactions as well as in a Mitsunobu reaction and cycloadditions. These studies proved that the linker is stable under a broad variety of reaction conditions and that the enzymatic method allows for release of the desired product alcohols under extremely mild conditions at pH 7 and 37 degrees C. In addition, the enzymatic reaction proceeds with complete chemoselectivity, that is other esters or amides are not attacked by the biocatalyst. In addition to alcohols amines can also be cleaved by means of the enzyme-initiated two-step process. In these cases the higher stability of amides as compared to esters requires warming to 60 degrees C to induce cyclization and release of the desired product. 相似文献
1000.
S. U. Karimova I. A. Israilov M. S. Yunusov S. Yu. Yunusov 《Chemistry of Natural Compounds》1980,16(2):177-180
From the epigeal part and roots ofGlaucium fimbrilligerum 22 alkaloids have been isolated, of which three have proved to be new — d-isocorytuberine, dehydrocorydine, and corydine N-oxide.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 224–228, March–April, 1980. 相似文献