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1.
V. B. Vol'eva T. I. Prokofeva A. I. Prokofev I. S. Belostotskaya N. L. Komissarova V. V. Ershov 《Russian Chemical Bulletin》1995,44(9):1720-1724
The interaction of 3,6-di-tert-butyl-ortho-benzoquinone (1) and 3,5-di-tert-butyl-ortho-benzoquinone (2) with NH3 in water—alcohol medium and with (NH4)2CO3 in a solid phase has been studied. Redox processes with participation of a nucleophile of the medium take place for1, while2 reacts with NH3 at the carbonyl group with transformation of the quinone imide. The mechanism of redox transformation of1 has been proposed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1789–1793, September, 1995.This work was carried out with financial support from the Russian Foundation for Basic Research (Project No. 94-03-08653). 相似文献
2.
V. I. Minkin M. S. Korobov R. Ya. Olekhnovich G. S. Borodkin L. E. Nivorozhkin 《Russian Chemical Bulletin》1995,44(11):2168-2171
Kinetics and reaction mechanisms governing inversion of the tetrahedral configuration at the metal center in the series ofbis-chelate Zn(II) complexes of 3,2-, 1,2-, and 2,1-oxy(mercapto)naphthaldimines, respectively4–6, have been studied with the use of dynamic1H NMR spectroscopy. A polytopal rearrangement of the diagonal twist type has been found to be an energetically preferable pathway of the inversion reaction for complexes4 and5 with a ZnN2O2 coordination site, whereas the inversion reaction for complexes with a ZnN2S2 coordination site occurs by an intramolecular dissociation-recombination pathway that involves cleavage of a Zn-N coordination bond. In the case of complexes6, the inversion reaction is governed mainly by intramolecular degenerate ligand exchange reactions.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11. pp. 2261–2265, November, 1995.This work was supported by the Russian Foundation for Basic Research (project No. 93-03-18692) and the International Science Foundation (grant No. RNJ 000). 相似文献
3.
A general method for the synthesis of 5-substituted indolizidines based on intramolecular cyclization oftrans- andcis-2-allyl-6-R-1,2,3,6-tetrahydropyridines, obtained from pyridine and triallylborane, has been elaborated. The closure of the
five-membered ring is carried out by hydroboration-oxidation followed by cyclization of the resulting δ-amino alcohols in
the presence of the Ph3P−CBr4−Et3N system. (Pr2BH)2 and Pr3B are used as the hydroborating reagents, and H2O2 in an acid medium is used for the oxidation of 2-[3-(dipropylboryl]-Δ2-piperideines formed. This method has been used for the synthesis of two natural alkaloids: indolizidine 209D (cis-5-hexylindolizidine) and itstrans-isomer were prepared fromcis- andtrans-2-allyl-6-hexyl-1,2,3,6-tetrahydropiridine, respectively; indolizidine 167B andtrans-5-propylindolizidine were synthesized fromcis- andtrans-2,6-diallyl-1,2,3,6-tetra-hydropyridine, respectively.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 971–979, May, 1998. 相似文献
4.
Yu. N. Bubnov E. A. Shagova S. V. Evchenko A. V. Ignatenko 《Russian Chemical Bulletin》1994,43(4):645-656
The reductivetrans-2,6-diallylation of pyridines with triallyl- and allyl(dialkyl)boranes has been discovered. Heating (40–100 °C) of pyridine, deuteropyridine, or 3-bromopyridine complexes with triallylborane in the presence of alcohols (ROH or CH3OD), water, or Et2NH results in the respectivetrans-2,6-diaIlyl-1,2,5,6-tetrahydropyridines (2,3,22, or25) in 20–97 % yields. A preparative method for the isomerization oftrans-2,6-diallyl compounds2 and25 into the respectivecis-isomers4 and28 by heating them with triallyl- or allyl(dialkyl)boranes (125–150 °C) has been suggested. The hydrogenation oftrans- orcis-2,6-diallyl-1,2,5,6-tetrahydropyridines gavetrans- orcis-2,6-dipropylpiperidines, respectively. Thecis- andtrans-configurations of compounds2 and4 were established by analyzing the NMR spectra ofN-benzyl (7 and13) andN,N-dimethyl (6 and 14) derivatives of piperidine derivatives5 and8. A possible mechanism for the reductive diallylation of pyridines has been discussed.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 693–704, April, 1994.This study was financially supported by the Russian Foundation for Basic Research (Project 93-03-18193). 相似文献
5.
D. N. Kravtsov V. M. Pachevskaya A. S. Peregudov E. I. Fedin 《Russian Chemical Bulletin》1995,44(7):1311-1315
A number of compounds of the type oftrans-4-FC6H4Pt(PAr3)2SC6H4F-4, where Ar is a substituted phenyl group, have been prepared starting from the corresponding chlorides. By exchange reactions oftrans-4-FC6H4Pt[P(C6H4F-4)3]2SC6H4F-4 with the above-mentioned compounds or Ar3P,trans-4-FC6H4Pt[P(C6H4F-4)3][PAr3]SC6H4F-4 have been generated in solution. For the latter compounds, the effect of Ar3P oncis- andtrans-ligands has been studied by the19F NMR technique. It has been shown that thecis- andtrans-effects of Ar3P run parallel and are well described by pK
a
values and ionization potentials of the unshared electron pair in Ar3P, as well as by 0 constants of the aryl groups.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1359–1363, July. 1995. 相似文献
6.
GC behavior of C6-C17
n-alkanes has been investigated at different temperatures of isothermal analysis and under temperature programming conditions using two capillary columns coated with OV-101 and OV-351 stationary phases. Temperature increments have been calculated for the homologs and their inequality has been demonstrated for each member of then-alkane series. It was shown that the nonlinear individual temperature variation of the energy of dispersive interaction ofn-alkane homologs with the stationary phase, which was observed under isothermal conditions, may be one of the main reasons for the nonlinear change in sorption parameters ofn-alkanes in temperature-programmed gas chromatography.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 642–645, April, 1994.The present work was carried out with the financial support of the Russian Foundation for Basic Research (Grant 93-03-4969). 相似文献
7.
V. V. Gritsenko O. A. D'yachenko N. D. Kushch N. G. Spitsina E. B. Yagubskii N. V. Avramenko M. N. Frolova 《Russian Chemical Bulletin》1994,43(7):1183-1185
Extraction of fullerenes from carbon soot by trichloroethylene has been studied. We have found that C60 forms a solvate with trichloroethylene (C60 · C2HCl3:a=31.31(1);b= 10.156(4);c=10.146(4) Å;V=3228.6 Å3,Z=4,d
calc=1.752 g cm–3, orthorhombic symmetry). Its thermal stability has been studied using TG and DSC. A phase transition of the first order at 167 K has been detected.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1248–1250, July, 1994.The authors are grateful to V. P. Bubnov and I. S. Krainskii for providing them with the samples of fulle-rene-containing carbon soot, and to M. G. Kaplunov and A. V. Zvarykina for assistance in the work.This work was carried out with the financial support of the Russian Foundation for Basic Research, Project Nos. 93-03-18705 and 93-03-5650. 相似文献
8.
3-N-Substituted 5-(1Z-carboxymethylene)-2-chloro-4,4-dimethoxycyclopent-2-en-1-ones have been prepared from the corresponding 3-N-substituted 5-allenyl-2,5-dichloro-4,4-dimethoxycyclopent-2-en-1-ones using selective oxidative cleavage of their allene
bond by the RuCl3−NaIO4 system.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1646–1648, September, 1997. 相似文献
9.
S. S. Bukalov L. A. Leites B. A. Antipova V. V. Dement'ev 《Russian Chemical Bulletin》1994,43(1):57-59
The temperature dependence of the Raman spectrum of solid dodecamethylcyclohexasilane Si6Me12 has been studied in the temperature interval 20–235 °C. At 72 °C the substance undergoes a phase transition of an «order-disorder» type, from the ordered crystalline modification to the plastic mesophase with isotropic molecular reorientations. This phase transition is accompanied by the appearance of a conformational equilibrium in the solid state. An analogous equilibrium is also observed in a benzene solution, where the concentration of the second conformer is already noticeable at 6 °C.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 63–65, January, 1994.This work was carried out with the financial support of the Russian Foundation for Basic Research, project No. 93-02-16242 相似文献
10.
V. F. Traven’ I. V. Ivanov A. V. Panov O. B. Safronova T. A. Chibisova 《Russian Chemical Bulletin》2008,57(9):1989-1995
Aromatic imines, namely, 5-formyl-6-hydroxy-4-methyl- and 8-formyl-7-hydroxy-4-methylcoumarin derivatives, have been synthesized.
A dependence of their spectral characteristics (1H NMR spectra, electronic absorption spectra) from the solvent (DMSO, CHCl3, DMF, acetonitrile, MeOH) has been studied. The solvatochromic effects observed for a number of imines, first of all, for
7-hydroxy-4-methyl-8-(4′-nitrophenylimino)methyl-2H-1-benzopyran-2-one, were related to their E/Z-isomerization with respect to the C=N bond based on the quantum chemical calculations by the AM1, PM3, PPP CI methods.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1954–1960, September, 2008. 相似文献
11.
The high TC
superconducting phase Bi2Sr2Ca2Cu3Ox
(2223) in the Pb-BSCCO system has been produced by EDTA-gel processing
using nitrate solutions. The precursor has heated in two stages, at 300 and
800°C each for 2 h, to avoid the burning of the important species involved
in the final product. The effects of time (6 to 48 h) and temperature (845
and 855°C) on the formation of the 2223 phase have been studied by sintering
the samples in air. Thermal analysis (TG/DTA), X-ray diffraction (XRD), scanning
electron microscopy (SEM) and a vibrating sample magnetometer (VSM) have been
employed to investigate the powder produced at different stages of decomposition,
oxidation and formation of sintered materials from the powders. The volume-fraction
of the 2223 phase at 845°C increases with time, the maximum value of the
2223 phase was obtained at 120 h. It has been observed that the formation
of the high TC phase
is remarkably enhanced at the temperature of the endothermic peak of the DTA
curve. The best result has been obtained in the sample sintered for 24 h at
the temperature 855°C (endothermic peak). This also indicated that at
855°C, the large volume-fraction of 2223 phase with TC
113 K grew in short time and as the sintering time increased, it decomposed
into the Bi2Sr2CaCu2Ox
(2212) phase and other phases. 相似文献
12.
A method for the synthesis of previously unknown 4,6-dinitro-2-trihalogenomethyl-2,3-dihydrobenzo[b]furans has been elaborated. The method is based on condensation of 2,4,6-trinitrotoluene with fluoral or chloral in the presence
of K2CO3 with subsequent intramolecular cyclization of the resulting 2-picryl-1-(trihalogenomethyl)ethanols.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 569–570, March, 2000. 相似文献
13.
Chiral monomer (M1 ), mesogenic and non-mesogenic crosslinking agents (C1 and C2 ), and the corresponding liquid crystalline elastomers (P1 and P2 series), have been synthesised. Their chemical structures have been characterised by Fourier transform infrared or 1H nuclear magnetic resonance and their phase behaviour investigated by differential scanning calorimetry, polarising optical miscoscopy, thermo-gravimetric analysis (TGA) and X-ray diffraction. The effect of the crosslinking unit on the phase behaviour of the elastomers has been studied. M1 showed a cholesteric oily streak and focal conic texture. C2 exhibited a nematic enantiotropic thread-like and schlieren texture, and a monotropic fan-shaped texture in the SA phase. Due to the introduction of the mesogenic crosslinking unit, elastomers, P2-1 ?P2-5 , exhibited a cholesteric phase, while elastomers, P1-1 ?P1-4 , derived from a non-mesogenic crosslinking unit, exhibit a SA phase. As the content of the crosslinking unit increased, the T g of the P1 series initially decreased and then increased, and the T i of the series decreased. In the P2 series the T g increased, but the T i initially increased and then decreased. TGA confirmed that all the elastomers had improved thermal stability. 相似文献
14.
T. V. Zinevich I. T. Chizhevsky A. I. Yanovsky P. V. Petrovskii L. I. Zakharkin 《Russian Chemical Bulletin》1997,46(11):1965-1966
The previously synthesized mixture of diastereomeric complexescloso-3,3-(η2,3-C7H7CH2)-1-(PhCH2)-3,1,2-RhC2B9H10 was separated by TLC on silica gel into individual diastereomers, whose stereochemistry and relative configurations were
determined by X-ray diffraction analysis.
Triplet- and quadruplet-like signals are marked with an asterisk
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2069–2070, November, 1997. 相似文献
15.
The effects of O−, N (CH3)2, NH (CH3), NH2, C2H5, CH3, OH, F, Cl, OF, Br, NO2 and substituents in para- and meta-positions on X-pyridineHF hydrogen bond has been studied by HF, B3LYP and MP2 methods using 6-311++G(d,p) basis set. The relationship between hydrogen bond formation energy ΔE and electron donating (or withdrawing) of substituents has been investigated. In this respect, population analysis has been performed by atoms in molecules (AIM) and natural bond orbital (NBO) theories. The results of AIM and NBO analyses are in good agreement with calculated energy values. The relationship between Hammett coefficient and complexation energy has been established and the ρ constant has been calculated for hydrogen bonding. There is a relationship between σ and ΔE with a correlation coefficient equal to 0.94. 相似文献
16.
2-(Methylthio)pentafluoropropene was obtained by dehydrofluorination of methyl 2H-hexafluoroisopropyl sulfide by the BF3 · NEt3 complex. Its reactivity with respect to allyl alcohol and hexamethyldisilazane was studied. The electrophilicity of 2-(methylthio)penta-fluoropropene was compared with the properties of terminal polyfluoroalkenes whose behavior in these reactions has been studied previously.Perfluoroisobutylene also reacts with allyl alcohol in the absence of protophilic agents.3,4Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 80–84, January, 1994. 相似文献
17.
D. N. Cheredilin E. V. Balagurova I. A. Godovikov S. P. Solodovnikov I. T. Chizhevsky 《Russian Chemical Bulletin》2005,54(11):2535-2539
The replacement of the PPh3 ligands in “three-bridge” exo-nido-ruthenacarborane 5,6,10-[RuCl(PPh3)2]-5,6,10-(μ-H)3-10-H-exo-nido-7,8-C2B9H8 with diphosphines, viz., 1,3-bis(diphenylphosphino)propane (dppp) or 1,4-bis(diphenylphosphino)butane (dppb) dramatically decreases the barrier to
the thermal exo-nido→closo rearrangement affording the chelate closo-complexes 3,3-[Ph2P(CH2)nPPh2]-3-H-3-Cl-closo-3,1,2-RuC2B9H11 (n = 3 or 4) under mild conditions. In the reaction with dppp, the rearrangement is accompanied by the formation of 17-electron
paramagnetic closo-ruthenacarborane 3,3-[Ph2P(CH2)3PPh2]-3-Cl-closo-3,1,2-RuC2B9H11, which could be isolated as the main product when the reaction was carried out at 80 °C.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2455–2459, November, 2005. 相似文献
18.
The crystal structure of the compound Li3Zn0.5GeO4 has been determined and refined by means of three-dimensionalFourier syntheses and least squares. Li3Zn0.5GeO4 crystallizes orthorhombic with space groupD
2h
16
-Pmnb (No. 62) and the lattice parametersa=6.29,b=10.74 andc=5.17 Å. The crystal structure consists of isolated [GeO4] tetrahedra, which are linked together by [(Li,Zn)O4] tetrahedra analogous to Li3PO4(h). An additional eight-fold position is partly occupied by two lithium atoms. The occupancy of this position may vary according to the observed range of composition, which lies between Li3.8Zn0.1GeO4 and Li2.6Zn0.7GeO4. 相似文献
19.
V. P. Feshin M. Yu. Kon'shin A. V. Radushev E. V. Feshina V. Yu. Gusev A. E. Lesnov V. I. Karmanov 《Russian Chemical Bulletin》1996,45(11):2505-2508
The basicity of hydrazides of the highest aliphatic carboxylic acids RC(O)NHNH2 (R = CnH2n+1,n = 5-12) has been studied by potentiometric titration, and IR and1H NMR spectroscopy.Ab initio Hartree-Fork calculations using the 6–31G* basis set with full optimization of geometry were carried out on the simplest acy1hydrazines and their possible protonated forms. Based on these calculations, and the 1R and1H NMR spectra, the tautomerism of alkylhydrazides and the structures of their protonated forms are discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2645–2649, November, 1996. 相似文献
20.
J. Couquelet M. Madesclaire F. Leal V. P. Zaitsev S. Kh. Sharipova 《Chemistry of Heterocyclic Compounds》2001,37(7):898-902
The reaction of (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediol with glutaraldehyde has been studied. It has been established on the basis of AM1 and PM3 calculations and 1H NMR spectra recorded in the presence of the shift reagent Eu(fod)3 that (1S,3S,4S,7R,11R)-3-(4-nitrophenyl)-11-aza-2,6-dioxatricyclo[5,3,1,04,11]undecane is formed as the result of the reaction. 相似文献