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1.
I. Yu. Grishin Yu. M. Chunaev N. M. Przhiylgovskaya I. I. Levina A. V. Metelitsa 《Chemistry of Heterocyclic Compounds》1992,28(1):48-52
Using the Stobbe condensation fulgides that undergo E, Z-isomerization on exposure to UV radiation are obtained from diethyl [2-(1,3,3-trimethyindoline-2-ilidene)ethylidene]succinate, and benzaldehyde and its derivatives; and from 1,2-dimethyl-3-formylindole and -formyl-1,3,3-trimethyl-2-methyleneindoline. The structure and photochemical changes of the fulgides were investigated by means of PMR.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 55–60, January, 1992. 相似文献
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4.
S. Yu. Kukushkin P. Yu. Ivanov L. M. Alekseeva V. I. Levina K. I. Kobrakov N. B. Grigor'ev V. G. Granik 《Russian Chemical Bulletin》2005,54(8):1887-1891
The half-wave potentials of polarographic reduction of the carbonyl group in unsubstituted and N-methyl- and N-phenylsulfonyl-substituted 1- and 4-oxotetrahydrocarbazoles and their reactivities in reactions with nucleophilic (NaBH4, malonodinitrile, and cyanoacetamide) and electrophilic (DMF dimethyl acetal) reagents were compared. 4-Oxotetrahydrocarbazoles
are much less reactive than 1-oxotetrahydrocarbazoles.
__________
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1832–1836, August, 2005. 相似文献
5.
A series of stable Cr(V) model complexes that mimic the binding of Cr(V) to peptide backbones at the C-terminus of proteins have been prepared for N,N-dimethylurea derivatives of the tripeptides Aib3-DMF, AibLAlaAib-DMF, and AibDAlaAib-DMF (Aib = 2-amino-2-methylpropanoic acid, DMF = N,N-dimethylformamide). The Cr(ll) precursor complexes were synthesized by the initial deprotonation of the amide and acid groups of the peptide ligands in DMF with potassium tert-butoxide in the presence of CrCl2. The Cr(II) intermediates thus formed were then immediately oxidized to Cr(V) using tert-butyl hydroperoxide. Spectroscopic and mass-spectrometric analyses of the Cr(V) complexes showed that a new metal-directed organic transformation of the ligand had occurred. This involved a DMF solvent molecule becoming covalently bound to the amine group of the peptide ligand, yielding a urea group, and a third coordinated deprotonated urea nitrogen donor. A metal-directed oxidative coupling has been proposed as a possible mechanism for the organic transformation. The Cr(V/IV) reduction potential was determined for the three Cr(V) complexes using cyclic voltammetry, and in all cases it was quasi-reversible. These are the first isolated and fully characterized Cr(V) complexes with non-sulfur-containing peptide ligands. 相似文献
6.
Kicha A. A. Kalinovskii A. I. Levina É. V. Rashkes Ya. B. Stonik V. A. Elyakov G. B. 《Chemistry of Natural Compounds》1985,21(3):332-337
From the glycoside fraction of the starfishPatiria pectinifera, after its desulfation, an artefactural glycoside has been obtained: 29(-L-arabinofuranosyloxy)-5-stigmastane-3,6,8,15,16-pentaol (I). The structure of (I) was shown by1H and13C NMR spectra and mass spectra and by acetylation and high-temperature hydrogenation.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Institute of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 356–361, May–June, 1985. 相似文献
7.
An aqua complex of copper(II) ortho-azidobenzoate was synthesized. The formula of this complex, [Cu(OH)ABA 2H2O]2 (ABA is ortho-azidobenzoate), was determined by IR, UV, and EPR spectroscopy and volumetric analysis (from the amount of nitrogen released upon dissolving the aqua complex in dry DMF). It was found that, in this aqua complex, the azido group is not coordinated to the copper(II) ion. On the dissolution of the aqua complex in dry organic solvents, such as DMF, DMSO, dioxane, and methanol, it underwent dehydration followed by the coordination of the azido group to copper(II) to convert into a chelate complex. The chelate complex in the solid state was stable at room temperature; however, it slowly degraded in solutions to liberate nitrogen. Dissolution in dry THF did not result in the dehydration of the complex. In the photolysis of the aqua complex in dry THF or a THF-water mixture, photochemical dehydration yielding the chelate complex occurred along with the degradation of the azido group and the formation of copper(II) anthranilate.Translated from Khimiya Vysokikh Energii, Vol. 39, No. 2, 2005, pp. 135–139.Original Russian Text Copyright © 2005 by Budruev, Levina, Karyakina, Oleinik.This revised version was published online in April 2005 with a corrected cover date. 相似文献
8.
Synthesis of 6α-methyl-16α,17α-cyclohexano-19-norprogesterone from a 19-methyl-6-desmethyl precursor
After prolonged refluxing of 19-tosyloxy-16α,17α-cyclohexanopregn-5-en-3β-ol-20-one (3) with NaI in 2-propanol, the initially formed 19-iodo derivative (4) undergoes supraface migration of the CH2I group from the C(10) atom to the C(6) atom, probably through involvement of a homoallyl cation. The resulting 6β-iodomethyl-16α,17α-cyclohexano-19-norpregn-5(10)-en-3β-ol
(5) was transformed in three steps into 6α-methyl-16α,17α-cyclohexano-19-norprogesterone (6α-methyl-19-nor-D′
6-pentarane,8). The transformation of compound5 into the target product8 also gave a side product, a pentarane with aromatic ringA (10), which was isolated and characterized by spectroscopic methods.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1688–1691, September, 1997. 相似文献
9.
A. A. Kicha A. I. Kalinovskii É. V. Levina P. V. Andriyashchenko 《Chemistry of Natural Compounds》1986,21(6):760-762
By repeated chromatography on Polikhrom-1, silica gel, and Florisil, ethanolic extracts of two species of starfish,Culcita novaeguineae andLinckia guildingi, have yielded the new steroid glycoside culcitoside C1 (I): 5-cholestan-3,4,6,8,15,24-hexaol 24-O-[2,4-di-O-methyl--D-xylopyranosyl-(12)--L-arabinofuranoside], C39H68O14, mp 245–248°C, []D -35.8°, c 0.6; methanol). Its structure was shown by the results of acid hydrolysis, acetylation and methylation, and1H and13C NMR spectroscopy.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 801–804, November–December, 1985. 相似文献
10.
Levina E. V. Kalinovskii A. I. Andriyashchenko P. V. Stonik V. A. Dmitrenok P. S. 《Russian Chemical Bulletin》2002,51(12):2295-2298
A new polyhydroxylated steroid (20R,24S)-5-cholestane-3,6,15,24-tetraol and a known glycoside, laeviuscoloside G, was isolated from the Far-Eastern starfish Henricia sanguinolenta, collected in the sea of Okhotsk, and characterized. 相似文献