Megastigmane Glycosides from Polygala hongkongensis Hemsl

Two new megastigmane glycosides,7Z-roseoside,and 7Z-trifostigmanoside Ⅰ,as well as,four known compounds,trifostigmanoside Ⅱ,epimedin C,3',7-dihydroxy-4'-methoxyisoflavone-7-D-glucopyranoside,and formenonetin,were isolated from Polygala hongkongensis Hemsl.The structures of the isolated compounds were established on the basis of UV,IR,NMR,and MS spectral data.Megastigmane glycosides(1-3)were isolated from the family Polygalaceae for the first time.     

Synthesis of 2-En-l-one-ebelactonyl Benzoates of Territrem B Analogues from Jujubogenin

Two series of territrem B analogues (10a-10c and 18) have been designed and synthesized from jujubogenin 5a which was prepared from jujubogenin glycosides 5b obtained from the leaves of Zizyphusjujuba. The structures of the new compounds were confirmed by 1H-,13C-NMR and MS data. Compounds 10c and 18 showed weak inhibitory effect on AChE at 10^-4 mol/E.     

1，3—Dipolar Cycloaddition of Substituted Benzonitrile Oxide to 5—（R）—（1—Menthyloxy）—2（5H）—furanone

Several isoxazoline compounds were obtained by the 1,3-dipolar cycloaddition of benzonitrile oxide to 5-(R)-(1-menthyloxy)-2(5H)-furanone. The reaction condition was investigated preliminarily, the structures of these compounds have been established via the analysis of NMR data (involved NOEID or HMBC) and the reaction seems occurred regioselectively.     

Two New C—21 Steroidal Glycosides from Cynanchum aurichulatum

Two new C-21 steroidal glycosides, cynanauriculoside I and cynanauriculoside Ⅱ, were isolated from the roots of Cynanchum aurichulatum. Their structures were established using spectroscopic methods including one and two-dimensional NMR.     

Synthesis and Vasodilatory Activities of New Pyrazolo[3,4—d] pyrimidin—4—one Derivatives

A series of pyrazole[3,4-d] pyrimidin-4-one derivatives were synthesized and tested for vasodilatory activities. All of them were new compounds and their structures were confirmed by IR,^1H NMR,MS and elemental analysis.     

The Synthesis and Regioselective Hydrolysis of Dialkyl 2—Phenylfuran （an 2—Phenyltetrahydrofuran）—3,4—dicarboxylates

Dialkyl 2-phenylfuran (and 2-phenyltetrahydrofuran)-3,4-dicarboxylates (1,2,5-7), wich are potential precursors of the synthesis of furofuran and tetrahydrofurofuran lignans, can be selectively hydrolyzed to monoacid(3,8) by potassium hydroxide. The regioselective hydrolysis was affected significantly by the 2-phenyl group of the furan or tetrahydrofuran skeleton. The geometric structures of 3,8 and related compounds were elucidated and verified by NMR spectra.     

Regioselective Synthesis and Base Catalyzed Transacylation of Substituted 1H—Pyrazole—4—carboxamides

New type of substituted 1H-pyrazole-4-carboxamides were obtained by regioselective synthesis under the catalysis of different based.The stuctures of the title compounds were confirmed by elemental analysis,^1H NMR,IR,MS and X-ray crystallography.Compounds 1 were transcaylated into their corresponding.Compounds 1 were transacylated into their corresponding amides 3 in the prsence of sodium hydride.Preliminary bioassays indicated that some compounds showed fungicidal activities against Rhizoctonia solani and Sclerotinia sclerotiorum.     

从富宁藤中得到的两类新的强心苷以及它们之间的可能的生源转化途径

Five novel cardiac glycosides with two types of unusual aglycone [funingenin A (2a) and B], named funingenosides E-I (2-6), together with a known compound, funingenoside B (1), were isolated from the aerial part of Parepigynumfuningense Tsiang et P. T. Li (Apocynaceae). The structures of 2-6 were elucidated by means of MS, IR, NMR spectral analyses and chemical degradation. The possible biogenetic pathway of the two types of cardiac glycosides was also discussed.     

Synthesis of 3—Biaryl—1—ferrocenyl—2—propene—1—ones

The novel structures of organometallic compounds 3-biaryl-1-ferrocenyl-2-propene-1-ones 5 were synthesized for nonlinear optical chromophores by Suzuki cross-coupling reaction.Their structures were determined with elemental analyses,^1H NMR spectra and ^13C NMR spectra.     

Syntheses and Olfactory Characters of Some Endo-α-Substituted-Bicyclo[2. 2. 2]-Octenyl (or Octanyl) Methanols

Sixteen title compounds were synthesized, twelve of which are new ones. Their structures were determined by 1H NMR, IR and MS, the refractive indices or melting points were measured. Odors of all the title compounds were evaluated and the structure-odor relationship was briefly discussed.     

Identification of C-21 steroidal glycosides from the roots of Cynanchum chekiangense by high-performance liquid chromatography/tandem mass spectrometry

High-performance liquid chromatography coupled with electrospray tandem mass spectrometry (HPLC/ESI-MS/MS) was used to identify C-21 steroidal glycosides with immunological activities in roots of Cynanchum chekiangense. In the MS/MS spectra, fragmentation reactions of the [M + Na]⁺ were recorded to provide structural information about the glycosyl and aglycone moieties. To further confirm the fragments structures, off-line Fourier transform ion cyclotron resonance tandem mass spectrometry (FT-ICR-MS/MS) was also performed. In the study, four known steroidal glycosides cynascyroside C, chekiangensosides A and B, glaucoside H, and four novel steroidal glycosides chekiangensosides C, D, E and chekiangensoside A isomer were identified based on mass spectral data, NMR spectral data and standards. This is the first report on identifying steroidal glycosides in roots of C. chekiangense by HPLC/ESI-MS/MS directly, which could save time and material consuming efforts in traditional phytochemistry analysis.     

Studies of iridoid glycosides using liquid chromatography/electrospray ionization tandem mass spectrometry

Fragmentation pathways of five iridoid glycosides have been studied by using electrospray ionization multi-stage tandem mass spectrometry (ESI-MS(n)). The first-stage MS data of the five iridoid glycosides were compared. The MS spectra showed that the adduct ions of iridoid glycosides and the formate anion were diagnostic ions to distinguish iridoid glycosides with a carboxyl group at the C-4 position or an ester group at the C-4 position. The MS fragmentation pathways of the five iridoid glycosides were also studied. Analyzing the product ion spectra of iridoid glycosides, some neutral losses were observed, such as H(2)O, CO(2) and glucose residues, which were very useful for the identification of the functional groups in the structures of iridoid glycosides. Furthermore, specific loss of one molecule of methyl 3-oxopropanoate or 3-oxopropanic acid was firstly discussed, which corresponded to the isomerization of the hemiacetal group in the structure of iridoid aglycone. According to the fragmentation mechanisms and HPLC/MS(n) data, the structures of five iridoid glycosides in a crude extract of Gardenia jasminoisdes fruit have been identified. Three compounds were compared with standards and the other two were identified as shanzhiside and genipin gentibioside by their MS(n) data without standard compounds. In order to further validate the veracity of the deduction, genipin gentiobioside was isolated from the extract of Gardenia jasminoisdes fruit using Purification Factory and was further identified by C- and H-NMR.     

N-linked oligosaccharide analysis of rat brain Thy-1 by liquid chromatography with graphitized carbon column/ion trap-Fourier transform ion cyclotron resonance mass spectrometry in positive and negative ion modes

We have previously described the site-specific glycosylation analysis of rat brain Thy-1 by LC/multistage tandem mass spectrometry (MS(n)) using proteinase-digested Thy-1. In the present study, detailed structures of oligosaccharides released from Thy-1 were elucidated by mass spectrometric oligosaccharide profiling using LC/MS with a graphitized carbon column (GCC-LC/MS). First, using model oligosaccharides, we improved the oligosaccharide profiling by ion trap mass spectrometry (IT-MS) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Sequential scanning of a full MS(1) scan with FT-ICR-MS followed by data-dependent MS(n) with IT-MS in positive ion mode, and a subsequent full MS(1) scan with FT-ICR-MS followed by data-dependent MS(n) with IT-MS in negative ion mode enabled the monosaccharide composition analysis as well as profiling and sequencing of both neutral and acidic oligosaccharides in a single analysis. The improved oligosaccharide profiling was applied to elucidation of N-linked oligosaccharides from Thy-1 isolated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It was demonstrated that Thy-1 possesses a significant variety of N-linked oligosaccharides, including Lewis a/x, Lewis b/y, and disialylated structure as a partial structure. Our method could be applicable to analysis of a small abundance of glycoproteins, and could become a powerful tool for glycoproteomics.     

Screening non-colored phenolics in red wines using liquid chromatography/ultraviolet and mass spectrometry/mass spectrometry libraries

Liquid chromatography/ultraviolet (LC/UV) and mass spectrometry/mass spectrometry (MS/MS) libraries containing 39 phenolic compounds were established by coupling a LC and an ion trap MS with an electrospray ionization (ESI) source, operated in negative ion mode. As a result, the deprotonated [M-H]- molecule was observed for all the analyzed compounds. Using MS/MS hydroxybenzoic acid and hydroxycinnamic acids showed a loss of CO2 and production of a [M-H-44]- fragment and as expected, the UV spectra of these two compounds were affected by their chemical structures. For flavonol and flavonol glycosides, the spectra of their glycosides and aglycones produced deprotonated [M-H]- and [A-H]- species, respectively, and their UV spectra each presented two major absorption peaks. The UV spectra and MS/MS data of flavan-3-ols and stilbenes were also investigated. Using the optimized LC/MS/MS analytical conditions, the phenolic extracts from six representative wine samples were analyzed and 31 phenolic compounds were detected, 26 of which were identified by searching the LC/UV and MS/MS libraries. Finally, the presence of phenolic compounds was confirmed in different wine samples using the LC/UV and LC/MS/MS libraries.     

Steroidal glycosides from Veronica chamaedrys L. Part I. The structures of chamaedrosides C, C1, C2, E, E1 and E2

Two new spirostane glycosides, chamaedrosides C (1) and C1 (2), two new furostane glycosides, chamaedrosides E (4) and E1 (5), and two new furospirostane glycosides, chamaedrosides C2 (3) and E2 (6), have been isolated from Veronica chamaedrys L. plants. Their structures were determined on the basis of chemical evidence and extensive spectroscopic methods, including 1D- and 2D-NMR experiments, as well as MS analysis. The given compounds have been found for the first time.     

Six New C21 Steroidal Glycosides from Cynanchum bungei Decne

Six new C₂₁ steroidal glycosides 1 – 6 were isolated from the stem parts of Cynanchum bungei Decne . The structures of the new glycosides were determined on the basis of spectroscopic analysis, including 1D‐ and 2D‐NMR and HR‐ESI‐MS techniques as well as by comparison of their spectral data with those of related compounds.     

Profiling of grape monoterpene glycosides (aroma precursors) by ultra‐high performance‐liquid chromatography‐high resolution mass spectrometry (UHPLC/QTOF)

A ‘suspect screening analysis’ method for grape metabolomics by ultra‐high performance‐liquid chromatography (UHPLC) and high‐resolution quadrupole‐time of flight (QTOF) mass spectrometry was recently developed. This method was applied to study grape monoterpene glycosides, the main grape aroma precursors. Since standard compounds were not available, they were tentatively identified by overlapping various analytical approaches, in agreement with the indications recommended in mass spectrometry (MS)‐based metabolomics. Accurate mass and isotopic pattern, MS/MS fragmentation, correlation between fragments observed and putative structures and between liquid chromatography coupled with mass spectrometry (LC/MS) and gas chromatography/mass spectrometry signals were studied. Seventeen monoterpene glycosides were identified without performing the hydrolytic artifacts commonly used to study these compounds which may affect sample profile. This is the first time that a detailed study of these aroma precursors has been carried out by direct LC/MS analysis. Copyright © 2014 John Wiley & Sons, Ltd.     

New Anthraquinone and Iridoid Glycosides from the Stems of Hedyotis hedyotidea

Five new anthraquinone glycosides, hedanthrosides A–E ( 1 – 5 , resp.) and two new iridoid glycosides, hediridosides A and B ( 6 and 7 , resp.), along with two known anthraquinones and four known iridoids, were isolated from the stems of Hedyotis hedyotidea (DC.) Merr . The structures of the new compounds were elucidated on the basis of 1D‐ and 2D‐NMR, and HR‐MS analysis and chemical methods.     

The glycosides from Lomatogonium rotatum

A new phenyl glycoside, 2-(3'-O-beta-D-glucopyranosyl)benzoyloxygentisic acid (1), along with seven known glycosides 2-8 was isolated from Tibetan herbal medicine Lomatogonium rotatum. The structures of the compounds were elucidated by spectroscopic methods including 1D and 2D NMR techniques and MS data.