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Mass Spectral Data (mass + spectral_data)
Selected AbstractsAroma-impact compounds in Lysimachia foenum-graecum extractsFLAVOUR AND FRAGRANCE JOURNAL, Issue 1 2009Na Shu Abstract Two different extraction methods were used to obtain representative extracts from stems and leaves of Lysimachia foenum-graecum, a Chinese plant with a smoky, spicy, green, woody and caramel aroma. An extract was obtained by steam distillation followed by pentane back-extraction. Plants were also extracted with dichloromethane, and the non-volatile compounds were separated from volatiles by high-vacuum distillation (SAFE). Compared to the steam distillate extract, the SAFE-distilled extract was judged to be more similar to the aroma of the starting materials. The aroma-impact compounds of the SAFE extract were then determined using multidimensional GC. From the detection frequencies and the intensities of the peaks, 47 peaks with odour-activity were determined, using an adaptation of the GC,SNIFF method, to have an impact on the overall aroma of the extract. Fifty-four compounds responsible for the peaks presenting odour-activity were identified from mass spectral data, retention indices, olfactory character and co-injection of authentic standards. Copyright © 2008 John Wiley & Sons, Ltd. [source] Analysis of the essential oil of Lippia graveolens HBK from El Salvador,FLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2001Gaston Vernin Abstract Essential oils from two samples of Lippia graveolens HBK (South American or Mexican oregano, common in El Salvador), were obtained by hydrodistillation and studied by GC and GC,MS. Forty-five compounds, constituting 92,93% of the oil, were identified. The two major components in both samples were carvacrol (71% and 34.6%, respectively) and thymol (5,7%, respectively). In addition, two unusual isomers, 2-isopropyl-4-methylphenol and 4-isopropyl-2-methylphenol, were found and identified by comparison with mass spectral data and retention indices and tentatively synthesized. Copyright © 2001 John Wiley & Sons, Ltd. [source] A new family of platinum(II) complexes incorporating five- and six-membered cyclic phosphine ligandsHETEROATOM CHEMISTRY, Issue 2 2010Andrea Kerényi New platinum complexes of the type cis -Pt(L)2Cl2 have been synthesized from five- and six-membered cyclic phosphines, which were prepared after deoxygenating a series of phosphine oxides (3-phospholene oxides, phospholane oxides, a 1,4-dihydrophosphinine oxide, and a 1,2,3,6-tetrahydrophosphinine oxide). The complexes were characterized by NMR and mass spectral data, and their stereostructures were elucidated by B3LYP/6-31G(d)-LANL2DZ ECP calculations. The phosphine intermediates were characterized as the corresponding phosphine-boranes. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:63,70, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20579 [source] Tetrakis-phthalocyanines bearing electron-withdrawing fluoro functionality: Synthesis, spectroscopy, and electrochemistryHETEROATOM CHEMISTRY, Issue 5 2009Ahmet T. Bilgiçli In this study, 2,9,16,23-tetrakis-4,-(2,3,5,6-tetrafluoro)-phenoxy-phthalocyaninatometalfree and metal(II) complexes, (H2PcBzF16, ZnPcOBzF16, CuPcOBzF16, and CoPcOBzF16) (Bz: Benzene) (2H, Zn, Cu, and Co), have been prepared directly from the corresponding 4,-(2,3,5,6-fluorophenylthio)-phthalonitrile compounds in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in high boiling quinoline solvent. Tetrafluoro atoms on 2,3,5,6-position of benzene at the peripheral sites of phthalocyanines (Pcs) give rise interesting solubility to tetrakismetallophthalocyanines. Although all complexes were soluble in DCM, CHCl3, THF, DMF, and DMSO with increasing order, complexes synthesized, particularly H2PcBzF16, CuPcOBzF16, have very limited solubility in DMF and DMSO. The complexes have been characterized by elemental analysis, FTIR, 1H NMR, UV,vis, and MALDI,TOF mass spectral data. The cyclic voltammetry and differential pulsed voltammetry of the complexes show that while H2PcBzF16, CuPcOBzF16, and ZnPcOBzF16 give ligand-based reduction and oxidation processes, CoPcOBzF16 gives both ligand and metal-based redox processes, in harmony with the common metallophthalocyanine complexes. Redox processes due to both aggregated and disaggregated species were simultaneously observed during the first reduction process. The nature of the metal-based redox processes was confirmed using spectroelectrochemical measurements. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:262,271, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20545 [source] Synthesis and antimicrobial activity of 2-substituted-2,3-dihydro-5-propoxy-1H -1,3,2-benzodiazaphosphole 2-OxidesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 1 2001M. Venugopal Several 2-alkylcarbamato/thiocarbamato/aryloxy/trichloromethyl-2,3-dihydro-5-propoxy-1H -1,3,2-benzodiazaphosphole 2-oxides (4 and 6) were synthesised by reacting 4-propoxy- o -phenylenediamine (1) with various N -dichlorophosphinyl carbamates (3), aryl phosphorodichloridates (5a-f) and trichloromethyl phosphonic dichloride (5g) in the presence of triethylamine at 45-65 °C. Their ir, 1H, 13C, 31P nmr and mass spectral data are discussed. The compounds were screened for antifungal activity against Curvularia lunata and Aspergillus niger and for antibacterial activity against Bacillus subtilis and Escherichia coli. Most of these compounds exhibited moderate activity in the assays. [source] MassBank: a public repository for sharing mass spectral data for life sciencesJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 7 2010Hisayuki Horai Abstract MassBank is the first public repository of mass spectra of small chemical compounds for life sciences (<3000 Da). The database contains 605 electron-ionization mass spectrometry(EI-MS), 137 fast atom bombardment MS and 9276 electrospray ionization (ESI)-MSn data of 2337 authentic compounds of metabolites, 11 545 EI-MS and 834 other-MS data of 10 286 volatile natural and synthetic compounds, and 3045 ESI-MS2 data of 679 synthetic drugs contributed by 16 research groups (January 2010). ESI-MS2 data were analyzed under nonstandardized, independent experimental conditions. MassBank is a distributed database. Each research group provides data from its own MassBank data servers distributed on the Internet. MassBank users can access either all of the MassBank data or a subset of the data by specifying one or more experimental conditions. In a spectral search to retrieve mass spectra similar to a query mass spectrum, the similarity score is calculated by a weighted cosine correlation in which weighting exponents on peak intensity and the mass-to-charge ratio are optimized to the ESI-MS2 data. MassBank also provides a merged spectrum for each compound prepared by merging the analyzed ESI-MS2 data on an identical compound under different collision-induced dissociation conditions. Data merging has significantly improved the precision of the identification of a chemical compound by 21,23% at a similarity score of 0.6. Thus, MassBank is useful for the identification of chemical compounds and the publication of experimental data. Copyright © 2010 John Wiley & Sons, Ltd. [source] linear free energy relationships;JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 11 2007UB3LYP/6-31G(d The substituent effect on the reactivity of the CN bond of molecular ions of 4-substituted N -(2-furylmethyl)anilines toward two dissociation pathways was studied. With this aim, six of these compounds were analyzed by mass spectrometry using electron ionization with energies between 7.8 and 69.9 eV. Also, the UB3LYP/6-31G (d,p) and UHF/6-31G (d, p) levels of theory were used to calculate the critical energies (reaction enthalpies at 0 K) of the processes that lead to the complementary ions [C5H5O]+ and [M , C5H5O]+, assuming structures that result from the heterolytic and homolytic CN bond cleavages of the molecular ions, respectively. A kinetic approach proposed in the 1960s was applied to the mass spectral data to obtain the relative rate coefficients for both dissociation channels from ratios of the peak intensities of these ions. Linear relationships were obtained between the logarithms of the relative rate coefficients and the calculated critical energies and other thermochemical properties, whose slopes showed to be conditioned by the energy provided to the compounds within the ion source. Moreover, it was found that the dissociation that leads to [C5H5O]+ is a process strongly dependent upon the electron withdrawing or donating properties of the substituent, favored by those factors that destabilize the molecular ion. On the contrary, the dissociation that leads to [M , C5H5O]+ is indifferent to the polar electronic effects of the substituent. The abundance of both products was governed by the rule of Stevenson,Audier, according to which the major ion is the one of less negative electronic affinity. Copyright © 2007 John Wiley & Sons, Ltd. [source] Evaluation of the reduction of imidazophenazine dye derivatives under fast-atom-bombardment mass-spectrometric conditions,JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 1 2006Marina V. Kosevich Abstract Satellite [M + 2]+, and [M + 3]+ peaks accompanying the common peak of the protonated molecule [M + H]+ that are known to indicate the occurrence of a reduction process were observed in the fast atom bombardment (FAB) mass spectra of imidazophenazine dye derivatives in glycerol matrix. The distribution of the abundances in the [M + nH]+ peak group varied noticeably for different derivatives. This indicated different levels of the reduction depending on the different structure variations of the studied molecules. In the search for correlations between the mass spectral pattern and the structural features of the dyes, ab initio HF/6-31++G** quantum chemical calculations were performed. They revealed that the abundances of the [M + 2]+, and [M + 3]+ ions show growth proportional to the decrease of the energy of the lowest unoccupied molecular orbital, i.e. proportional to the increase of the electron affinity of the dye molecule. A method for rapid screening of reductive properties of sets of dye derivatives on the basis of the FAB mass spectral data is discussed. Copyright © 2005 John Wiley & Sons, Ltd. [source] Detection of intact megaDalton protein assemblies of vanillyl-alcohol oxidase by mass spectrometryPROTEIN SCIENCE, Issue 3 2000Willem J. H. Van Berkel Abstract Well-resolved ion signals of intact large protein assemblies, with molecular masses extending above one million Dalton, have been detected and mass analyzed using electrospray ionization mass spectrometry, with an uncertainty in mass of <0.2%. the mass spectral data seem to reflect known solution-phase behavior of the studied protein assembly and have therefore been directly used to probe the protein assembly topology and stability as a function of ionic strength and ph. [source] ICPLQuant , A software for non-isobaric isotopic labeling proteomicsPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 2 2010Achim Brunner Abstract The main goal of many proteomics experiments is an accurate and rapid quantification and identification of regulated proteins in complex biological samples. The bottleneck in quantitative proteomics remains the availability of efficient software to evaluate and quantify the tremendous amount of mass spectral data acquired during a proteomics project. A new software suite, ICPLQuant, has been developed to accurately quantify isotope-coded protein label (ICPL)-labeled peptides on the MS level during LC-MALDI and peptide mass fingerprint experiments. The tool is able to generate a list of differentially regulated peptide precursors for subsequent MS/MS experiments, minimizing time-consuming acquisition and interpretation of MS/MS data. ICPLQuant is based on two independent units. Unit 1 performs ICPL multiplex detection and quantification and proposes peptides to be identified by MS/MS. Unit 2 combines MASCOT MS/MS protein identification with the quantitative data and produces a protein/peptide list with all the relevant information accessible for further data mining. The accuracy of quantification, selection of peptides for MS/MS-identification and the automated output of a protein list of regulated proteins are demonstrated by the comparative analysis of four different mixtures of three proteins (Ovalbumin, Horseradish Peroxidase and Rabbit Albumin) spiked into the complex protein background of the DGPF Proteome Marker. [source] IntelliMS: A platform to efficiently manage and visualize tandem mass spectral dataPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 23-24 2008Min-Seok Kwon Abstract With the development of high-speed mass spectrometric techniques, it becomes important to manage large amounts of spectrometric data accurately. We have developed a new data management system with a visualization function named IntelliMS, which can load data into a search engine, filter out the insignificant data, create diagrams of the identification process from spectra to protein and share all the resulting datasets. This software can be used to efficiently manage complicated mass spectral data and the corresponding protein identification information obtained from various proteomics analyses. [source] A method for the identification of the double-bond position of isomeric linear tetradecenols and related compounds based on mass spectra of dimethyl disulfide derivativesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 1 2002Gu Yuan A simple method is presented for calculation of the double-bond position in linear tetradecenols based on mass spectral data of dimethyl disulfide derivatives. In this approach, the m/z ratios of the molecular ion and of one (or both) of the two most abundant fragment ions were utilized to calculate the double-bond position, without the requirement to identify both fragment ions resulting from carbon-carbon cleavage across what was originally the double bond. The approach was tested with mass spectra of dimethyl disulfide derivatives of 12 isomeric tetradecenols, and the double-bond position in each isomer was successfully identified by this method. The method was shown to work also for the corresponding acetates. Copyright © 2001 John Wiley & Sons, Ltd. [source] Antitumour activity of synthetic curcuminoid analogues (1,7-diaryl-1,6-heptadiene-3,5-diones) and their copper complexesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 8 2006V. D. John Abstract Four new curcuminoid analogues, 1,7-bis(4-hydroxyphenyl)-1,6-heptadiene-3,5-dione, 1a; 1,7-di(2-furyl)-1,6-heptadiene-3,5-dione, 1b; 1,7-di(2-naphthyl)-1,6-heptadiene-3,5-dione, 1c; 1,7-bis(2-chlorophenyl)-1,6-heptadiene-3,5-dione, 1d; and their copper(II) complexes of ML2 stoichiometry were synthesized and characterized by UV, IR, 1H NMR, ESR and mass spectral data. The compounds were investigated for their possible cytotoxic and antitumour activities. It was found that copper chelates are remarkably active compared with free curcuminoid analogues. All the compounds were found to be cytotoxic towards Ehrlich ascites carcinoma cells and cultured L929 (lung fibroblast cells). In the case of culture studies, concentrations needed for 50% cell death were around 5 µg/ml for copper complexes and 10 µg/ml for curcuminoid analogues. Copper complex of 1a with hydroxyl group in the phenyl ring was found to be most active towards L929cells (1 µg/ml produced 43.3 ± 1.3% cell death). Compound 1b, which possesses a furyl ring system, was found to show least activity towards increase in life span of tumour-bearing mice (increase in life span 39.31%). Copper chelates of all curcuminoid analogues showed a significant reduction (p < 0.001) of solid tumour volume in mice. Copyright © 2005 John Wiley & Sons, Ltd. [source] Synthesis of 4-(4-Methylsulfonylphenyl)-3-phenyl-2(3H)-thiazole Thione Derivatives as New Potential COX-2 InhibitorsCHINESE JOURNAL OF CHEMISTRY, Issue 6 2006Saeed Emami Abstract Synthesis of novel 4-(4-methylsulfonylphenyl)-3-phenyl-2(3H)-thiazole thione derivatives with functionalized diarylheterocycle pharmacophore as potential COX-2 inhibitors was described. The title compounds were synth- esized by cyclocondensation of corresponding dithiocarbamate and 2-bromo-1-(4-methylsulfonylphenyl)ethanone, followed by dehydration with H2SO4. All of the target compounds were characterized by 1H NMR, IR and mass spectral data. [source] | ||||||||||||||||||||||