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1.
N. I. Kalinovskaya T. A. Kuznetsova A. I. Kalinovsky V. A. Denisenko V. I. Svetashev L. A. Romaneko 《Russian Chemical Bulletin》2000,49(1):169-173
A mixture of 1(3),2-di-O-acyl-3(1)-O-β-gentiobiosylglycerols was isolated from a sea isolate ofBacillus pumilus. The components of the mixture were structurally characterized by mass spectrometry and1H and13C NMR spectroscopy data for the native compounds and their derivatives. The predominant component contains two C15 acyl groups, while the second component contains C15 and C17 fatty acids. Six minor components differ in residues of fatty acids and/or their combinations.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 166–170, January, 2000. 相似文献
2.
Ezzat T. M. Selim 《Journal of Chemical Sciences》1982,91(4):359-369
Using mass spectrometric technique, the effect of geometrical isomerism on the first and higher appearance energy values for
C4H3
+, C4H7
+ and C3H,3
+ ions obtained from cis-2-butene andtrans-2-butene is reported. The structure in the ionization efficiency curves (studied for 9 eV above threshold) for the same ions
obtained from the two isomers is reported and compared. It is believed that at threshold C4H7
+ fragment is formed from the two isomers as methallyl ion. For C3H3
+ fragment formed from the cw-isomer at threshold the proposed structure is the propargyl ion with ΔHf equal to 279-4 kcal/mole while for that ion obtained fromtransisomer the proposed structure is the allenyl ion with ΔHf equal to 296.6 kcal/mole. 相似文献
3.
Characterization of ganoderma spore lipid by stable carbon isotope analysis: implications for authentication 总被引:2,自引:0,他引:2
Liu X Xu SP Wang JH Yuan JP Guo LX Li X Huang XN 《Analytical and bioanalytical chemistry》2007,388(3):723-731
The ratios of stable carbon isotopes (13C/12C) of ganoderma fruiting body, ganoderma spore, ganoderma spore lipid (GSL) and individual fatty acids in GSL were determined
by gas chromatography–stable isotope ratio mass spectrometry and elemental analysis–stable isotope ratio mass spectrometry.
These values fall into a range from −26.9 to −23.3‰, suggesting that the cut log as the Ganoderma-cultivated substrate in Fujian, China, may belong to C3 plants. Eighteen fatty acids were identified and their abundances
measured by gas chromatography–mass spectrometry in the six GSL samples with C16:0, C18:0, C18:1 and C18:2 as major constituents, and C16:1 is evidently enriched compared with the other edible vegetable oils. On the basis of the compositions of fatty acids and
stable carbon isotopes in GSL, we have developed a novel method to detect the adulteration of GSL products with cheaper edible
vegetable oils. An example of ideal blending between GSL and C4 or C3 vegetable oil is further provided to expound the discrimination
procedures and corresponding sensitive indicators. Simultaneously, the carbon isotope fractionation in the biosynthesis of
individual fatty acids was observed, revealing that the formation of C18:0 from C16:0 in ganodema spores had no conspicuous 13C enrichment of +0.4‰ for Ganoderma sinensis spore and +0.1‰ for G. lucidum spore; the desaturation of C18:0 to C18:1 resulted in a distinct 13C depletion of −1.4‰ for G. sinensis spore and −0.9‰ for G. lucidum spore; and the next desaturation from C18:1 to C18:2 displayed no evident 13C fractionation of −0.1‰ for G. sinensis spore and −0.2‰ for G. lucidum spore.
Figure
Ganoderma lucidum has been widely used in traditional Chinese medicines. Ganoderma spore lipid (GSL) extracted from the spores of G. lucidum has been approved as a health food supplement. However, because of rarity, GSL has become a target for adulteration with
cheaper vegetable oils. 相似文献
4.
Jing Sun Guichen Chen Xianen Zhao Wenhua Xu Guoying Zhou Youji Han Jinmao You 《Chromatographia》2007,65(7-8):469-476
A simple and sensitive high-performance liquid chromatographic (HPLC) method with fluorescence detection and mass spectrometric
identification has been developed for analysis of 30 long-chain and short-chain free fatty acids (FFAs). The fatty acids were
derivatized to their esters with 1-[2-(p-toluenesulfonate)ethyl]-2-phenylimidazole-[4,5-f]-9,10-phenanthrene (TSPP) in N,N-dimethylformamide (DMF) at 90 °C with anhydrous K2CO3 as catalyst. A mixture of C1–C30 fatty acids was completely separated within 60 min by gradient elution on a reversed-phase C8 column. Qualitative identification of the acids was performed by atmospheric-pressure chemical ionization mass spectrometry
(APCI–MS) in positive-ion mode. The fluorescence excitation and emission wavelengths were 260 and 380 nm, respectively. Quantitative
determination of the 30 acids in two Tibetan medicines Gentiana straminea and G. dahurica was performed. The results indicated that the medicines contained many FFAs. Linear correlation coefficients for the FFA
derivatives were >0.9991. Relative standard deviations (RSDs, n = 6) for the fatty acid derivatives were <3%. Detection limits (at a signal-to-noise ratio of 3:1) were 3.1–38 fmol. When
the fatty acid derivatives were determined in the two real samples results were satisfactory and the sensitivity and reproducibility
of the method were good. 相似文献
5.
G. P. Smirnova 《Russian Chemical Bulletin》1990,49(1):159-164
Gangliosides were isolated from the starfishEvasterias echinosoma and their structures were elucidated by chemical and physicochemical methods. Two major gangliosides were found to be disialogangliosides,
whose carbohydrate chain is based on the trisaccharide β-N-acylgalactosaminyl-(l→3)-β-galactosyl-(l→4)-β-glucose (acyl is formyl or acetyl), both residue at of 8-O-methyl-N-acetylneuraminic acid being attached to theN-acylgalactosamine residue at positions 3 and 6. The minor components are disialogangliosides with linear carbohydrate chains
in which the terminal sialic acid residue is attached to the penultimateN-acetylneuraminic acid residue at positions 4, 8, or 9. The lipid part of the gangliosides consists of sphingenine and unsubstituted
fatty acids (mainly, palmitic and stearic acids).
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 156–161, January, 2000. 相似文献
6.
Radiation chemical reactions of•OH, O•−, N3
•and e
aq
t-
witho- and m-hydroxycinnamic acids were studied. The second-orderrateconstantsforthereaction of•OH with ortho and meta isomers in buffer solution at pH7 are 3.9±0.2 × 109 and 4.4 ± 0.3 × 109 dm3 mol-1 s-1 respectively. At pH 3 the rate with the ortho isomer was halved (1.6 ± 0.4 × 109 dm3 mol-1 s-1) but it was unaffected in the case of meta isomer (k = 4.2±0.6 × 109dm3mol-1 s-1). The rate constant in the reaction of N3
• with the ortho isomer is lower by an order of magnitude (k = 4.9 ± 0.4 × 108 dm3 mol-1s-1). The rates of the reaction of e
aq
t-
with ortho and meta isomers were found to be diffusion controlled. The transient absorption spectrum measured in the•OH witho-hydroxycinnamic acid exhibited an absorption maximum at 360 nm and in meta isomer the spectrum was blue-shifted (330 nm)
with a shoulder at 390 nm. A peak at 420 nm was observed in the reaction of Obb−with theo-isomer whereas the meta isomer has a maximum at 390 and a broad shoulder at 450 nm. In the reaction of the absorption peaks
were centred at 370–380 nm in both the isomers. The underlying reaction mechanism is discussed. 相似文献
7.
Uwe Himmelreich Reiner Häßner Philip Thomas Frank Tschwatschal Rolf Borsdorf 《Monatshefte für Chemie / Chemical Monthly》1990,121(11):923-930
Summary NMR-spectroscopic investigations of substituted dithiocarbacinic acid derivatives show the existence of configurational isomers relative to the C=N double bond, but no tautomerism. We applied chemical shift differences in the1H-,13C- and15N-NMR-spectra, N - H and C - H coupling constants and NOE difference measurements in the solvents CDCl3,DMSO-d
6 and partly CD3OD in order to discriminate between the isomers and to determine the configurational composition. Compounds4 and5 exist asE-isomers in all solvents, compounds1, 2 and3 as a mixture ofE/Z-isomers. InDMSO-d
6 theE-form is the preferred isomer. 相似文献
8.
The hydrogenation of 2-tert-butylphenol was studied in regard to possibilities of influencing selectivity, namely the ratio ofcis- andtrans-isomers of 2-tert-butylcyclohexanol in the final reaction mixture. The hydrogenation reactions were carried out using the catalyst Ni/Al2O3. During the hydrogenations, a higher content of thecis-isomer was attained, when simultaneously the final reaction mixture contained 2-tert-butylcyclohexanone. The content of this intermediate, which primarily hydrogenated to thecis-isomer, increased with a decreased pressure and after the addition of acetic acid into the reaction mixture. 相似文献
9.
The 2-cyclohexenones1 a andd resp. react with urea in HCl/EtOH to give 1-hydroxy-4-methyl-7-phenyl- and 1-hydroxy-2,4-diazabicyclo[3.3.1]nonane-3-ones3a and3d resp., whereas the 2-cyclohexenones1b andc resp. transformed by urea to 1,7-dimethyl- and 1-methyl-4-ureido-2,4-diazabicyclo[3.3.1]nonan-3-ones9b andc resp. In the condensation of isophorone1e with urea a product C13H28N8O4 of indisdinct structure was formed, whereas the bicyclus3e could not be isolated.Reaction ofAcOAc with3a yielded the 5-methyl-3-oxo-7-phenyl-2,4-diazabicyclo[3.3.1]non-1-ylacetate (15); on heating of3a with acids decomposition to1a and urea took place. NoWagner-Meerwein-rearrangement was observed. The MS-spectra of3a andd are discussed; NMR- and IR-data are reported.No significant herbicidal, fungicidal or insecticidal activity was found in screening-tests on3a. 相似文献
10.
Verardo G Pagani E Geatti P Martinuzzi P 《Analytical and bioanalytical chemistry》2003,376(5):659-667
The composition of the surface waxes of three apple ( Malus domestica L.) cultivars ("Florina", "Golden B" and "Ozark Gold") has been studied by means of spectroscopic and GC–MS analysis of the class-fractionated mixture of components. Odd n -alkanes, mainly C27 and C29 molecules, are prevalent in the saturated fraction. Small concentrations of alkenes were also found; the C28:1 component is strongly (72%) in excess over the other 1-alkenes. Straight-chain esters (mainly of palmitic acid) of saturated primary alcohols (C18–C30) were also detected; whereas the acyl moiety is made up essentially of an even number of carbons, the alcohol counterpart does not exhibit this characteristic. Aldehydes are present (C20–C30) with the homologue patterns C26–C30 most strongly represented. Straight-chain free secondary alcohols characterize the waxes of "Florina" and "Ozark Gold"; the hydroxy function is located far from the extremity of the carbon framework. Outstanding is the presence of three alcohols with 29 carbon centres. These alcohols are accompanied by free straight-chain primary alcohols, mainly with even-numbered carbon chains in the range C26–C30. Free fatty acids are present; all of have a framework of even-numbered carbon chains mainly in the range C16–C20. C18:1 (oleic acid) is well represented. 相似文献
11.
Ferrous phosphites FeHPO3·3 H2O, FeH2P2O5, FeH4P2O6·1/2 H2O and FeH10P4O12·4 H2O were studied using X-ray powder patterns, thermography, electron reflectance spectroscopy, magnetic susceptibility measurements andRaman and infrared molecular spectra. The results obtained indicate that all the phosphites studied contain an approximately octahedral coordination sphere consisting of oxygen atoms, which produces a weak crystal field around the iron atom. Phosphite FeHPO3·3 H2O contains an HPO3
2– anion with the symmetry decreased from point groupC
3v toC
s. Ferrous diphosphite FeH2P2O5 contains a non-linear P–O–P bond with a valence angle of 159°. The hydrogen bonds between the water molecule and the HPO3
2– anion indicate a positive hydratation of the phosphite anion. Medium-strong or strong hydrogen bonds, 258–270 pm long, correspond to mutual interactions of the anions in the crystal lattice of hydrogenphosphites. Hydrogen bonding in hydrogenphosphites causes a decrease in theDq values. 相似文献
12.
Raman and infrared spectra of polycrystalline6Li2C2O4 and7Li2C2O4 have been investigated in the wavenumber region from 1,800 to 40 cm–1. The internal C2O4
–2 vibrations have been studied on the basis of a D2h molecular structure and the correlation field splittings have been found to be about 40 cm–1 for the stretching modes and about 15 cm–1 for the bending modes. The external vibrations of the Li+ and C2O4
–2 sites have been discussed by considering the results of the factor group analysis and the6Li/7Li isotope effect on the normal vibrations.
Raman- und Infrarot-Spektren von6Li2C2O4 und7Li2C2O4
Zusammenfassung Es wurdenRaman- und IR-Spektren von polykristallinem6Li2C2O4 und7Li2C2O4 im Bereich der Wellenzahlen von 1800 bis 40 cm–1 untersucht. Die internen Schwingungen wurden auf der Basis einer D2h Molekülstruktur analysiert. Für die Streckschwingungen wurde eine Korrelationsaufspaltung von etwa 40 cm–1 gefunden, für die Deformationsschwingungen etwa 15 cm–1. Die Diskussion der externen Schwingungen von Li+ und C2O4 –2 erfolgte unter Berücksichtigung der Resultate der Faktorgruppenanalyse und des6Li/7Li Isotopeneffekts auf die Normalschwingungen.相似文献
13.
Several plant products are known to exhibit immense medicinal value against human diseases. Our earlier studies showed that
dry stem crude extract (DSCE) ofTinospora cordifolia contained a polyclonal B cell mitogen, G1-4A. DSCE as well as G1-4A also enhanced immune response in mice. In order to explore
the possibility of using G1-4A/PPI (partially purified immunomodulator) to modulate radiation induced immunosuppression, the
antioxidant effect of PPI from this plant was examined against reactive oxygen and nitrogen species (ROS/RNS), generated by
photosensitization/peroxynitrite. Levels of lipid peroxidation products, superoxide dismutase (SOD) and catalase in liver/spleen
homogenate from mouse were monitored. Photosensitization induced significant increase in thiobarbituric acid reactive substances
(TBARS) in liver. The activities of SOD and catalase were reduced considerably. PPI, present during photosensitisation, prevented
lipid peroxidation and restored the activities of both the enzymes. Likewise, oxidative damage induced by peroxynitrite was
inhibited by PPI. The degradation of proteins due to photosensitization as assessed by SDS-PAGE was effectively reduced by
simultaneous treatment with PPI during photosensitization. Selective inhibitors of ROS like mannitol, SOD, sodium azide and
antioxidants, GSH and vitamin C brought about significant inhibition of formation of TBARS suggesting possible involvement
of O2
•,•OH and1O2. Photosensitization in deuterated buffer enhanced formation of TBARS thus indicating generation of1O2. Thus, the action of PPI may be against oxidative damage through Type I and II photosensitization mechanisms. Therefore,
the immunomodulator fromTinospora cordifolia may also be beneficial as an antioxidant. 相似文献
14.
M. S. Yunusov E. M. Tsyrlina E. D. Khairitdinova L. V. Spirikhin A. Yu. Kovalevsky M. Yu. Antipin 《Russian Chemical Bulletin》2000,49(9):1629-1633
A new alkaloid, anhydrolycaconitine (C36H46N2O9), was isolated from roots ofAconitum septentrionale K. Based on the results of1H and13C NMR and IR spectroscopy and mass spectrometry of the alkaloid and the product of its alkaline hydrolysis and on the data
of X-ray diffraction analysis of the hydrolysis product, the structure of 1α, 6β, 14α, 16β-tetramethoxy-7-oxo-18-succinylanthranoyloxy-17-(7→8)abeo-aconane was assigned to anhydrolycaconitine.
Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1640–1644, September, 2000. 相似文献
15.
A. S. Lobach A. A. Perov A. I. Rebrov O. S. Roshchupkina V. A. Tkacheva A. N. Stepanov 《Russian Chemical Bulletin》1997,46(4):641-648
Fullerene hydrides were prepared by hydrogenation of fullerences C60 and C70 using proton transfer from 9,10-dihydroanthracene to fullerene and were studied by mass spectrometry (electron impact, field
desorption), IR, UV, and1H and13C NMR spectroscopy. The main product of the hydrogenation of C60 is C60H36, which is sufficiently stable. Hydrogenation of fullerene C70 gives a series of polyhydrides C70H
n
(n=36–46), and the main product is C70H36. The dehydrogenation of C60H36 by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone is not quantitative and results in the formation of fullerene derivatives along
with C60. The comparison of the IR and1H and13C NMR spectral data for solid C60H36 with the theoretical calculations suggests that the fullerene hydride has aT-symmetric structure and contains four isolated benzenoid rings located at tetrahedral positions on the surface of the closed
skeleton of the molecule.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 4, pp. 671–678, April, 1997. 相似文献
16.
二氧化锰(MnO2)材料具有比容量大、电极电位高、储量丰富以及价格低廉等优势,成为水系锌电池正极最受关注的一类材料,然而其仍然存在着结构稳定性差和电化学储存机理复杂的问题。因此,我们通过两步合成法制备了一种花苞状结构的MnO2负载在Ti3C2Tx表面形成Ti3C2Tx/MnO2复合材料,通过X射线粉末衍射(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)对复合样品的结构、成分和形貌进行表征。通过将Ti3C2Tx/MnO2复合材料作为正极,与锌负极匹配组装成水系锌电池,研究了其分别在2 mol·L-1 ZnSO4、2 mol·L-1 ZnSO4+0.1 mol·L-1 MnSO4、30 mol·L-1三氟甲基磺酸四乙基铵(TEAOTf)+1 mol·L-1三氟甲烷磺酸锌(ZnOTf)和3 mol·L-1 ZnOTf四种电解液中的电化学性能。结果表明,Ti3C2Tx/MnO2在2 mol·L-1 ZnSO4中的比容量较高,但循环稳定性很差。将TEAOTf盐和ZnOTf盐共溶于水中,设计了一种新型的含惰性阳离子的超高浓度盐包水电解液(30 mol·L-1 TEAOTf+1 mol·L-1 ZnOTf),不仅提高了Ti3C2Tx/MnO2材料的可逆性,而且有效抑制了电极材料在循环过程中的溶解。 相似文献
17.
Starch materials of different amylose content were allowed to react with saturated and unsaturated fatty acids of varying
chain length from C14 to C18 under homogeneous conditions applying the solvent N,N-dimethyl acetamide in combination with LiCl. As reagent the corresponding acid chlorides and, alternatively, carboxylic acids
in situ activated with toluene-4-sulfonyl chloride and N,N′-carbonyldiimidazole (CDI) were studied. Using fatty acid chlorides (FACl) and toluene-4-sulfonyl chloride-activated acids
an almost complete substitution of the starch occurs. By in situ activation of the fatty acids with CDI, products with a degree of substitution up to 2 were obtained, which, in particular,
represents a simple and very mild procedure. 相似文献
18.
1H MAS NMR and15N NMR studies of adsorbed N2 and N2O molecules were used to characterize Br?nsted and Lewis acidic sites of unmodified γ-Al2O3 and γ-Al2O3 modified with NaOH. Changes in the concentrations of surface hydroxyls with the increase in the number of more “basic” OH
groups for NaOH/γ-Al2O3 have been found by1H MAS NMR experiments. Two different types of Lewis acidic sites in γ-Al2O3 have been revealed using15N NMR studies. The strongest sites are poisoned even at small NaOH concentrations (ca. 0.05 wt.%). Not only the number of electron-accepting sites but also their strength are supposed to decrease for modified
γ-alumina. 相似文献
19.
E. I. Yudanova D. V. Konarev L. L. Gumanov R. N. Lyubovskaya 《Russian Chemical Bulletin》1999,48(4):718-721
Complexes of fullerenes C60 and C70 with cobalt(II) and manganese(II) tetraphenylporphyrinates of compositions Mn(TPP)·(C60)2(CS2)1.5 (1), Mn(TPP)·C70(CS2)
x
, wherex<=1.25 (2), Co(TPP)·C60(CS2)0.5 (3), and Co(TPP)·C70(CS2)
x
, wherex<0.25 (4), were synthesized and studied by ESR spectroscopy. At 77 K, complexes1 and2 have singlet ESR spectra characteristic of the low-spin (S=1/2) state of MnII, withg=2.002 and linewidths of 250 G and 300 G, respectively, and differing significantly from that of the initial MnII(TPP) (g
1=5.9 andg=2.0,S=5/2). The spectra of complexes1 and2 exposed to oxygen exhibit hyperfine structure due to interaction with55Mn and14N nuclei. The ESR spectra of complexes3 and4 are asymmetric (<g>=2.4, ΔH
pp=(500–600) G), which is due to the overlap of parallel and perpendicular spectral components. The absence of ESR signals from
C60
.− and C70
.− radical anions makes it possible to conclude that the formation of complexes1–4 is not accompanied by electron transfer from Co(TPP) and Mn(TPP) to fullerences C60 and C70.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 722–725, April, 1999. 相似文献
20.
Horst Bögel 《Theoretical chemistry accounts》1983,63(5):395-399
Nickel(0)-olefine π-complexes such as Ni(C2H4)3 and Ni(C2H4)(PR3)2 [6] prepared by conventional ligand replacement reaction are diamagnetic and stable up to room temperature. Similar π-complexes
e.g. Ni(C2H4)
n
(withn = 1, 2 or 3) generated by cryo-condensation technique [3] may exist in a paramagnetic state which derives from the triplet
ground state of the atomic nickel. The stability of (η2-ethylene) nickel has been explained byab initio-MO calculations relating the energies of the complexes to different terms (1
S and3
F) of the nickel atom.
相似文献