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Summary. A novel ionic catalyst, 1-butyl-4-aza-1-azoniabicyclo[2.2.2]octane chloride based on 1,4-diazabicyclo[2.2.2]octane was synthesized
and applied in the Baylis-Hillman reaction, which occurred readily at room temperature to afford the corresponding adducts in good yield. The ionic catalyst
could be recycled for seven runs without diminution in its catalytic activity. 相似文献
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Kamaluddin Abdur-Rashid Tara P. Dasgupta John Burgess 《Transition Metal Chemistry》2005,30(8):948-956
Solubilities in t-BuOH–, i-PrOH–, and EtOH–H2O mixtures at 298.2 K are reported for a number of salts of mono- and bi-nuclear cobalt(III) complexes. From these solubilities
and published single ion transfer chemical potentials, on the TATB (Ph4As +≡ BPh4-) assumption, transfer chemical potentials have been derived for most of these cobalt(III) complexes. The results and trends
are discussed in relation to those for other ions and complexes. Effects of ligand nature for transfer to t-BuOH–H2O mixtures are detailed and, for a selection of complexes, trends for transfer of a given complex to t-BuOH–, i-PrOH–, EtOH– , and MeOH– H2O mixtures are compared. 相似文献
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This review summarizes all significant data regarding peroxynitrite chemistry, the ways of its synthetic preparation as well
as the degradative action of this species on biomolecules, in particular glycosaminoglycans, among which the hyaluronan degradation
by peroxynitrite has recently been the subject of greater interest than ever before. The complex chemical behavior of a peroxynitrite
molecule is strongly influenced by a few factors; conformational structural forms, active intermediates release, presence
of CO2 and trace transition metals, different reaction conditions, as well as the rules of kinetics. Special attention was focused
on monitoring of the kinetics of the degradative action of peroxynitrite in or without the presence of residual hydrogen peroxide
on high-molar-mass hyaluronan. 相似文献
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Anita Kovács I. Csóka Magdolna Kónya E. Csányi A. Fehér I. Erős 《Journal of Thermal Analysis and Calorimetry》2005,82(2):491-497
Summary The properties of the inner and the external aqueous phases, were studied in w/o/w multiple emulsions with light microscopic image analysis and differential scanning calorimetry (DSC). The importance of multiple
emulsions lies in the presence of these aqueous phases, making them available for sustained, controlled drug delivery systems.
Differentiation of these two aqueous phases, studying the effect of manufacturing technology on droplet structure, quantitative
determination of phase volumes and any changes occurring during storage are essential when planning w/o/w emulsions. The present study uses microscopic observations combined with DSC measurements in order to identify the formed
structure, at developmental stage in case of different components, preparation methods, and stirring rates. These tools are
beneficial during manufacturing as in process controls, or to ensure product quality. 相似文献
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A. D. Dubonosov V. P. Rybalkin Ya. Yu. Vorob’eva V. A. Bren’ V. I. Minkin S. M. Aldoshin V. V. Tkachev A. V. Tsukanov 《Russian Chemical Bulletin》2004,53(10):2248-2252
It was shown by electron absorption spectroscopy and X-ray diffraction analysis that steric strains in photochromic 2-(N-acyl-N-arylaminomethylene) benzo[b]thiophen-3(2H)-one molecules ortho-substituted in the N-phenyl ring increase the quantum yield of the N→O photoinduced rearrangement in accord with an increase in the steric constant of the ortho-substituent.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2151–2155, October, 2004. 相似文献
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V. V. Islamova N. A. Kucher V. I. Poltavtsev 《Russian Journal of Applied Chemistry》2009,82(8):1408-1412
We obtained an analytical solution of a problem of unsteady mass transfer under the equilibrium condition y = Ax + B to compare results with a problem solution in the case of equilibrium condition looking as y = Ax. 相似文献
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M. Grin’ko V. Kulcitki N. Ungur A. Barba K. Delyanu P. F. Vlad 《Chemistry of Natural Compounds》2007,43(3):277-281
Several α,ω-bifunctional derivatives of E,E,E-geranylgeraniol were prepared via convergent synthesis starting with geraniol (8), which was converted in three steps into the tetrahydropyranyl ether of 8-chlorogeraniol (9) and 8-hydroxygeranylphenylsulfone (10). Combination of synthons 9 and 10 with subsequent reductive removal of the phenylsulfonyl group produced the tetrahydropyranyl ether of ω-hydroxygeranylgeraniol (5), hydrolysis of which gave exclusively trans-ω-hydroxygeranylgeraniol (1). Derivatives 5–7 of geranylgeraniol were synthesized using standard methods.
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Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 231–234, May–June, 2007. 相似文献
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G. A. Abakumov V. K. Cherkasov T. N. Kocherova N. O. Druzhkov Yu. A. Kurskii M. P. Bubnov G. K. Fukin L. G. Abakumova 《Russian Chemical Bulletin》2007,56(9):1849-1856
New sterically hindered functionalized o-quinones were synthesized by the 1,4-nucleophilic addition of secondary cyclic amines to 3,6-di(tert-butyl)-o-benzoquinone. The ability of these o-quinones to form o-semiquinone complexes with transition and main-group metals was studied by ESR spectroscopy in solution.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1786–1793, September, 2007. 相似文献
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I. V. Kulakov 《Chemistry of Natural Compounds》2009,45(4):522-524
Condensation of the monosaccharides D-glucose and D-galactose with synthesized halo-substituted p-phenylenediamines and 4-amino-2,6-dibromophenol was studied. It was found that glycosylation occurred only at the 4-amino
group that was sterically unhindered by the halogen atom. The position of the aglycon in the glycoside was established by
PMR spectroscopy. 相似文献
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An attempt to link the heat of reaction obtained from analysis of UV spectra, bond energies deduced from crystallographic
data and calorimetric measurements of [bis(d-, l-, and dl-alaninato)diaqua] nickel(II) dihydrate complexes to theoretical values obtained from calculation is described. The heat of
reaction, which includes energy of ligand exchange in addition to crystal field stabilization energy of the three complexes,
was calculated from changes in spectral shifts, bond lengths, and free energy between nickel(II) ion and the d-, l-, and dl-alanine complexed nickel(II) ion in aqueous solution. These investigations were done by UV–visible spectroscopy, X-ray crystallography,
and isothermal calorimetry. The results reveal that the experimental heat of reaction based on the three mentioned parameters
is in good agreement with the theoretical value. The results are found to be of considerable interest in its linking of spectrochemical
quantities with thermodynamic functions. 相似文献
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M. Madesclaire V. P. Zaitsev J. V. Zaitseva S. Kh. Sharipova 《Chemistry of Heterocyclic Compounds》2007,43(10):1325-1332
A synthesis is reported for (4R,5R)-and (4S,5S)-4-hydroxymethyl-5-(4-nitrophenyl)oxazolidin-2-ones and (1′R,4R)-and (1′S,4S)-4-[hydroxy(4-nitrophenyl)methyl]oxazolidin-2-ones from (1R,2R)-and (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediols. The effect of the experimental conditions on the formation of these compounds
was studied.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1562–1570, October, 2007. 相似文献
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A new method is proposed for the synthesis of indole derivatives containing a chiral substituent at the nitrogen atom, which
includes the direct alkylation of indole derivatives with tert-butyl (2S)-(p-tolylsulfonyloxy)propionate, obtained from commercial
ethyl (S)-lactate with subsequent conversion to the corresponding p-toluenesulfonyloxy derivative by hydrolysis, and esterification.
Dedicated to Academician B. A. Trofimov on his 70th birthday.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, 1391–1398, September, 2008. 相似文献
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M. G. Voronkov N. N. Vlasova O. Yu. Grigor’eva Yu. N. Pozhidaev S. A. Bol’shakova 《Russian Journal of General Chemistry》2005,75(7):1091-1093
Condensation of (aminomethyl)triethoxysilane with thiocarbamide in the presence of catalytic amounts of ammonium sulfate was used to synthesize N,N-bis(triethoxysilylmethyl)thiocarbamide. The latter was brought into oxidative hydrolytic polycondensation with H2O2 to obtain poly[N,N′-bis(silsesquioxanylmethyl)thiocarbamide S, S-dioxide] whose properties were compared with the properties of poly[N,N′-bis(silsesquioxanylpropyl)thiocarbamide S,S-dioxide]. Both polymers in highly acidic media rather strongly absorb Ag(I), while at pH 7 they reduce most absorbed Ag+ to the metal. Their reaction with potassium permanganate involves reduction of Mn7+ to Mn4+. The first polymer is a less effective sorbent and redox agent than the second.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 7, 2005, pp. 1154–1156.Original Russian Text Copyright © 2005 by Voronkov, Vlasova, Grigor’eva, Pozhidaev, Bol’shakova. 相似文献
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