共查询到20条相似文献,搜索用时 31 毫秒
1.
R. I. Dzhalmakhanbetova S. A. Ivasenko A. T. Kulyyasov B. B. Khasenov N. B. Kurmankulov S. M. Adekenov 《Chemistry of Natural Compounds》2004,40(4):381-386
New phosphorus-containing derivatives of grosshemin were synthesized in 68-70% yield by reacting this guaianolide with dialkylphosphites. Their structures were established by IR, PMR, 13C NMR, and 31P NMR spectroscopies and two-dimensional 1H-1H NMR spectroscopy (COSY). The reaction of grosshemin with dialkylphosphites was found to be highly stereoselective. 相似文献
2.
R. I. Dzhalmakhanbetova B. B. Rakhimova N. A. Talzhanov G. K. Rustembekova A. T. Kulyyasov S. M. Adekenov 《Chemistry of Natural Compounds》2002,38(6):549-552
Novel isoalantolactone dialkylphosphonates were synthesized in 70-87% yields by reacting this eudesmanolide with dialkylphosphites. Their structures were proved by spectral analysis using IR, PMR, 13C and 31P NMR, and two-dimensional 1H-1H (COSY) spectroscopy. The reaction of isoalantolactone with dialkylphosphites is highly stereoselective. 相似文献
3.
Vladislav Yu. KorotaevAlexey Yu. Barkov Pavel A. SlepukhinMikhail I. Kodess Vyacheslav Ya. Sosnovskikh 《Tetrahedron letters》2011,52(23):3029-3032
A new type of ring-chain tautomerism, which consists of the reversible conversion of bicyclo[4.2.0]octane derivatives into trisubstituted enamines was found and studied by 1H NMR spectroscopy. The starting materials were prepared by the stereoselective reaction of (E)-3,3,3-trichloro-1-nitropropene with cyclohexanone enamines. 相似文献
4.
3-Methylfurazans with nitrogen-containing substituents at position 4 were studied by 1H, 13C, and 14N NMR spectroscopy. A correlation between the chemical shifts in 13C NMR spectra of these furazans and monosubstituted benzenes with the same substituents was found. The increments for a number of furazan-containing substituents were determined for the first time. 相似文献
5.
Arrigo Forni Irene Moretti Adele Mucci Fabio Prati Luisa Schenetti 《Chemistry of Heterocyclic Compounds》1995,31(9):1071-1078
A confrgurational and conformational study of NH, N-acetyl- and N-sulfonylaziridine carboxylates is performed by1H ,13C,17O, and15N NMR spectroscopy. The presence of acetyl and su fonyl groups on the ring nitrogen atom seems to reduce greatly the configurational stability at nitrogen.Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1226–1234, September, 1995. 相似文献
6.
A. A. Korlyukov N. V. Alekseev K. V. Pavlov O. V. Krivolapova V. G. Lakhtin E. A. Chernyshev M. Yu. Antipin 《Russian Chemical Bulletin》2005,54(7):1623-1626
The reaction of adamantane-1-carboxylic acid chloride with trichlorogermylmethanol afforded (trichlorogermyl)methyl adamantane-1-carboxylate,
whose molecular structure was established by 1H NMR spectroscopy and X-ray diffraction analysis.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1576–1579, July, 2005. 相似文献
7.
S. N. Tandura S. P. Kolesnikov M. P. Egorov K. S. Nosov O. M. Nefedov 《Russian Chemical Bulletin》1997,46(3):602-604
Assignment of all of the signals in the1H and13C NMR spectra of 1,1-dichloro-2,3,4,5-tetraphenyl-l-germacyclopenta-2,4-diene has been carried out using two-dimensional NMR
spectroscopy.
Translated fromIzvestiya Akademii Nauk Seriya Khimicheskaya, No. 3, pp. 623–625, March, 1997. 相似文献
8.
The Reaction Activity of Aromatic Carbonyl Compounds with Diphenylphosphine Oxide Studied by 31P NMR
Jinyun Zheng Xiangming Feng Yujian Yu Xiaomin Zhen Yufen Zhao 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):1080-1087
Abstract A series of α-hydroxyphosphine oxides were prepared by the reactions of diphenylphosphine oxide and aromatic carbonyl compounds and characterized by 1H NMR, 13C NMR, 31P NMR, FT-IR, ESI-MS, and HR-MS spectra. The reaction rates and experimental conditions of aromatic aldehydes and aromatic ketones were obviously different due to the activity of their carbonyls. The different substituents of the aromatic aldehydes affected the reaction rate too, and the quantitative reactivity of their substituent conformed to the Hammett equation. The results were confirmed by 31P NMR spectroscopy. 相似文献
9.
Stereochemistry of 7-aryl-1,7,8,8a-tetrahydro-3(2H)-indolizinones was studied by1H and13C NMR. Complete assignment of1H NMR signals and analysis of1H-1H coupling constants were performed using the iterative PANIC program. Values of3
J
6,7,3
J
7,8endo, and4
J
5,7 allow one to unambiguously identify the correspondingexo- andendo-stereoisomers. For stereoisomers with exo-orientation of H(7), complete assignment of13C NMR signals was performed on the basis of analysis of the13C-1H coupling constants using two dimensional heteronuclear shift-correlating spectroscopy.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 591–593, March, 1996. 相似文献
10.
Soufiane Touil Hedi Zantour 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):183-192
Abstract The reaction of imines 1 with monochlorophosphines leads to β-phosphorylketones obtained in the ketonic 2 or enolic forms 2′. The structure of all obtained products is confirmed by NMR and IR spectroscopy. 相似文献
11.
Jean-François Pilichowski Myriam Morel Farba Tamboura Stefan Chmela Jacques Lacoste 《Polymer Degradation and Stability》2010,95(9):1575-4515
4-13C-isoprene was prepared by the Wittig reaction. All reaction steps were optimised using unlabelled compounds. By reaction with triphenyl phosphine, 13C labelled methyl iodide afforded labelled methyl-triphenyl phosphine iodide in 84% yield. This reacted with meth acrolein with production of 4-13C-isoprene in 64% yield. Labelled polyisoprene was prepared by anionic polymerisation initiated by t-butyl lithium. Based on 13CH3I the overall yield is ca 30%. The polymer was characterized by 1H and 13C NMR spectroscopy. The contribution of each microstructure was [cis 1-4, 72%]; [trans 1-4, 10%]; [3-4, 18%]. 相似文献
12.
Rajendra K. JangidNeelima Gupta Raj K. Bansal Moritz von HopffgartenGernot Frenking 《Tetrahedron letters》2011,52(14):1721-1724
Theoretical calculations at the DFT (B3LYP/6-31+G**) level of the model Diels-Alder (DA) reactions of 1-methyl-3-(methoxycarbonyl)-2-phosphaindolizine with 1,3-butadiene in the presence of methylaluminium dichloride reveal that the co-ordination of organoaluminium reagent to the carbonyl oxygen increases the activation barrier compared to that for the uncomplexed 2-phosphaindolizine. On the other hand, co-ordination of the organoaluminium reagent to the σ2, λ3 P atom lowers the activation barrier by ∼6 kcal mol−1. 1-Methyl-2-phosphaindolizines having an electron-withdrawing group at the 3-position only undergo DA reaction with 2,3-dimethylbutadiene in the presence of the ethylaluminium dichloride catalyst in methylene chloride at a low temperature to afford [2+4] cycloadducts. The formation of an intermediate having the ethylaluminium reagent co-ordinated to σ2, λ3 P atom has been detected by 31P NMR. The products have been characterized by 31P and 1H NMR studies. 相似文献
13.
M. A. M. Khouna M. T. Ben Dhia M. R. Khaddar 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1673-1682
The two octahedral complexes SnCl4·2(O)PF(NR2)2 (R = Me or Et) were prepared from reaction of SnCl4 with the ligand (R2N)2P(O)F in anhydrous CHCl3. The new adducts have been characterized by elemental analysis, IR, and multinuclear (119Sn, 31P, 19F, and 1H) NMR spectroscopy. The NMR data show that the adducts exist in solution as a mixture of cis and trans isomers with markedly different proportions. When compared with previously described hexamethylphosphoramide (HMPA) and trimethylphosphate (TMPA) analogues, our results indicate that the cis isomer is the predominant species in solution. Low temperature 31P and 119Sn NMR spectra show that the compounds partially dissociate in dichloromethane. 相似文献
14.
S. A. Woznesensky A. A. Dudinov L. I. Belen'kii M. I. Struchkova V. N. Nesterov M. M. Krayushkin Yu. T. Struchkov 《Russian Chemical Bulletin》1997,46(3):501-506
The reactions of 1-aryl-5,5-dichloropenta-2,4-dien-1-ones with ethyl acetoacetate in the presence of EtONa give ethyl 4-aryl-6-(2,2-dichlorovinyl)-4-hydroxy-2-oxocyclohexane-carboxylates.
The structures of the reaction products were confirmed by1H and13C NMR spectroscopy and by X-ray diffraction analysis.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 相似文献
15.
Treatment of diphenylchloroborane with 1 equiv of pyridine or pyridine-N-oxide in CD2Cl2 formed the corresponding 1:1 adduct, which gave tricoordinate diphenylboron cation by electrophilic abstraction of chloride ion with the strong Lewis acid, SbCl5. The experimental 11B chemical shifts were in good agreement with the ab initio calculation results and the optimized structures were well explicable by 11B, 13C, and 121Sb NMR spectroscopy. 相似文献
16.
Data on the NMR spectroscopy of C, N, O, Si, P, and Sn donor atoms of platinum metal complexes in solutions are surveyed. The chemical shift of a donor atom mainly depends on the ligand in the trans-position (due to the trans-effect). The chemical shift of a donor atom on a particular coordinate of the complex (coordinate shift, CSh) is an attribute of this coordinate and can be used to identify such a coordinate in platinum metal complexes and to determine the structures of complexes. Based on the known data, CSh diagrams were composed for 1H, 13C, 14N, 17O, 19F, 31P, and 119Sn. Examples of using the CShs for determining the structures of platinum metal complexes in solutions are presented. 相似文献
17.
A complex mixture of fluoro-polyphosphates (FPPs) and polyphosphates was prepared by heating a mixture of NaF and sodium tripolyphosphate (STPP) at 600 °C in nitrogen atmosphere. Two-dimensional 31P-19F heteronuclear correlation spectroscopy (HETCOR) NMR was developed in identifying the atomic connection between F and P in the mixed FPPs. 19F, 31P and 31P-31P correlation spectroscopy (COSY) NMR methods were employed to identify the components of the mixture and measure the chain length of each FPP ingredient. NMR results clearly demonstrated that the mixture contains four kinds of fluoro-phosphates with different chain length of polyphosphate, which are monofluoro-phosphate (MFP), monofluoro-dipolyphosphate (MFDPP), monofluoro-tripolyphosphate (MFTPP) and difluoro-tripolyphosphate (DFTPP). Other phosphates and polyphosphates also were found in the mixture. 相似文献
18.
K. Doudin 《Polymer Degradation and Stability》2009,94(10):1599-1614
Grafted GMA on EPR samples were prepared in a Thermo-Haake internal mixer by free radical melt grafting reactions in the absence (conventional system; EPR-g-GMACONV) and presence of the reactive comonomer divinyl benzene, DVB (EPR-g-GMADVB). The GMA-homopolymer (poly-GMA), a major side reaction product in the conventional system, was almost completely absent in the DVB-containing system, the latter also resulted in a much higher level of GMA grafting. A comprehensive microstructure analysis of the formed poly-GMA was performed based on one-dimensional 1H and 13C NMR spectroscopy and the complete spectral assignments were supported by two-dimensional NMR techniques based on long range two and three bond order carbon-proton couplings from HMBC (Heteronuclear Multiple Bond Coherence) and that of one bond carbon-proton couplings from HSQC (Heteronuclear Single Quantum Coherence), as well as the use of Distortionless Enhancement by Polarization Transfer (DEPT) NMR spectroscopy. The unambiguous analysis of the stereochemical configuration of poly-GMA was further used to help understand the microstructures of the GMA-grafts obtained in the two different free radical melt grafting reactions, the conventional and comonomer-containing systems. In the grafted GMA, in the conventional system (EPR-g-GMACONV), the methylene protons of the GMA were found to be sensitive to tetrad configurational sequences and the results showed that 56% of the GMA sequence in the graft is in atactic configuration and 42% is in syndiotactic configuration whereas the poly-GMA was predominantly syndiotactic. The differences in the microstructures of the graft in the conventional EPR-g-GMACONV and the DVB-containing (EPR-g-GMADVB) systems is also reported 相似文献
19.
Shigehiko Takegami Kisho Watanabe Atsuko Konishi Tatsuya Kitade 《Journal of Dispersion Science and Technology》2018,39(7):1040-1046
We prepared novel ionic liquid submicron particles (ILSPs) in water by emulsifying the ionic liquid (IL) N-(2-methoxyethyl)-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr12O1TFSI), which is immiscible with water, with the nonionic surfactants Tween 20 and Span 80. The mean particle size and zeta potential of the ILSPs were about 580?nm and ?30?mV, respectively. The ILSPs were characterized using 1H and 19F nuclear magnetic resonance (NMR) spectroscopic methods. The chemical shifts of the Pyr12O1+ cation and TFSI? anion in the 1H and 19F NMR spectra of the ILSP suspension were consistent with those corresponding to pure Pyr12O1TFSI. This indicated that most of the Pyr12O1TFSI was still in the IL state in the ILSP suspension. In addition, 1H–1H nuclear Overhauser effect correlated spectroscopic measurements showed that the ILSP droplets contained Pyr12O1TFSI in the neat IL steric state even in the ILSP suspension, and Pyr12O1TFSI species localized in the droplet surfaces interacted with the hydrophobic acyl side chains of the surfactants. These NMR spectroscopic results show that the ILSPs formed an IL-in-water microemulsion in which droplets of neat Pyr12O1TFSI were surrounded by the two surfactants, that is, Tween 20 and Span 80. 相似文献
20.
The degraded Eucalyptus pellita kraft lignin from the black liquor of KP-AQ pulping was precipitated directly at pH ∼2.0 without further purifying, since the lignin obtained is more representative with a whole distribution of molecular weight. The precipitated lignin was fractionated into six fractions by successive extraction with organic solvents. A comparison study of the lignin heterogeneity between the fractions was made in terms of fractional yield, content of associated polysaccharides, alkaline nitrobenzene oxidation, molecular weight distribution, 1H NMR and 13C NMR spectroscopy and thermal stability. It was found that the lignin fractions contained higher associated hemicelluloses and ratios of non-condensed syringyl/guaiacyl units which were extracted by organic solvents with higher Hildebrand solubility parameters. The results from GPC and TGA showed that the polydispersity and the thermal stability of the lignin fractions increased with increasing molecular weight. In the low molecular weight fraction, small amounts of β-aryl ether bond (β-O-4) surviving the KP-AQ pulping were detected by both 1H and 13C NMR spectra. 相似文献