Home About us Contact
|
Home About us Contact | ||
|
|
||
NOESY
Terms modified by NOESY Selected AbstractsSecondary Metabolites of Phomopsis sp.EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 18 2009XZ-2, an Endophytic Fungus from Camptothecaacuminate Abstract Eleven new metabolites, including nine lovastatin analogues [oblongolides N,V (1,2 and 5,11), which were defined as naphthalene-type fungal polyketides], one linear furanopolyketide (13) and a monoterpene named dihydroxysabinane (14), together with four known compounds including oblongolides B (3) and C (4), one linear furanopolyketide (12) and the sesterterpene terpestacin (15), were isolated from the endophytic fungal strain Phomopsis sp. XZ-26 of Camptotheca acuminate. Their structures were elucidated by spectroscopic analyses including HR-ESI-MS, 1H and 13C NMR, 2D NMR (HMQC, HMBC, 1H- 1H COSY and NOESY), and X-ray single-crystal analysis. The antimicrobial activities of 1,5, 8, 10 and 13,15 were evaluated, but none showed a substantial effect. Additionally, a hypothetical biosynthetic pathway for oblongolides was proposed.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Solution structure of the functional domain of Paracoccus denitrificans cytochrome c552 in the reduced stateFEBS JOURNAL, Issue 13 2000Primo, Pristov In order to determine the solution structure of Paracoccus denitrificans cytochrome c552 by NMR, we cloned and isotopically labeled a 10.5-kDa soluble fragment (100 residues) containing the functional domain of the 18.2-kDa membrane-bound protein. Using uniformly 15N-enriched samples of cytochrome c552 in the reduced state, a variety of two-dimensional and three-dimensional heteronuclear double-resonance NMR experiments was employed to achieve complete 1H and 15N assignments. A total of 1893 distance restraints was derived from homonuclear 2D-NOESY and heteronuclear 3D-NOESY spectra; 1486 meaningful restraints were used in the structure calculations. After restrained energy minimization a family of 20 structures was obtained with rmsd values of 0.56 ± 0.10 Ĺ and 1.09 ± 0.09 Ĺ for the backbone and heavy atoms, respectively. The overall topology is similar to that seen in previously reported models of this class of proteins. The global fold consists of two long helices at the N-terminus and C-terminus and three shorter helices surrounding the heme moiety; the helices are connected by well-defined loops. Comparison with the X-ray structure shows some minor differences in the positions of the Trp57 and Phe65 side-chain rings as well as the heme propionate groups. [source] The identity of the O-specific polysaccharide structure of Citrobacter strains from serogroups O2, O20 and O25 and immunochemical characterisation of C. youngae PCM 1507 (O2a,1b) and related strainsFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 1-2 2003gorzata Miesza Abstract Serological studies using SDS,PAGE and immunoblotting revealed that from five strains that are ascribed to Citrobacter serogroup O2, four strains, PCM 1494, PCM 1495, PCM 1496 and PCM 1507, are reactive with specific anti- Citrobacter O2 serum. In contrast, strain PCM 1573 did not react with anti- Citrobacter O2 serum and, hence, does not belong to serogroup O2. The LPS of Citrobacter youngae O2a,1b (strain PCM 1507) was degraded under mild acidic conditions and the O-specific polysaccharide (OPS) released was isolated by gel chromatography. Sugar and methylation analyses along with 1H- and 13C-NMR spectroscopy, including two-dimensional 1H,1H COSY, TOCSY, NOESY and 1H,13C HSQC experiments, showed that the repeating unit of the OPS has the following structure: NMR spectroscopic studies demonstrated that Citrobacter werkmanii O20 and C. youngae O25 have the same OPS structure as C. youngae O2. Sugar and methylation analyses of the core oligosaccharide fractions demonstrated structural differences in the lipopolysaccharide core regions of these strains, which may substantiate their classification in different serogroups. [source] 2,3-,-Epoxyjaeschkeanadiol 5-benzoate from Ferula hermonis BoissFLAVOUR AND FRAGRANCE JOURNAL, Issue 6 2001Youssef Diab Abstract The new 2,3-,-epoxyjaeschkeanadiol 5-benzoate has been isolated and its 1H- and 13C-NMR signals were completely assigned by the application of the modern NMR techniques. Its conformations are discussed on the basis of molecular modelling calculations and nuclear Overhauser effect spectroscopy (NOESY) spectra. Copyright © 2001 John Wiley & Sons, Ltd. [source] New Chemical Constituents from Borreria verticillata (Rubiaceae)HELVETICA CHIMICA ACTA, Issue 9 2010Vinicius F. Moreira Abstract A phytochemical study on Borreria verticillata has led to the isolation of two novel simple indole alkaloids, 6-methoxy-4-(3-methylbut-2-en-1-yl)-1H -indole, named verticillatine A (1), and 1-(1H -indol-6-yl)-3-methylbutan-1-one, named verticillatine B (2), one new iridoid, 6,- O -(2-glyceryl)scandoside methyl ester (3), with the glycerol unit linked to a glucose unit, and two known ones, asperuloside (4) and scandoside methyl ester (5). The structures of these compounds were elucidated on the basis of spectroscopic-data analyses, mainly 1H- and 13C-NMR, including 2D experiments (1H,1H-COSY, NOESY, HMBC, and HMQC), and HR-ESI-MS. [source] Two New Secolignans from the Roots of Urtica fissa E. PritzHELVETICA CHIMICA ACTA, Issue 5 2009Bao-Quan Ji Abstract Two new secolignans, {(3S,4S)-4-[bis(4-hydroxy-3-methoxyphenyl)methyl]-2-oxotetrahydrofuran-3-yl}methyl , - D -glucopyranoside (1) and its stereoisomer {(3S,4R)-4-[bis(4-hydroxy-3-methoxyphenyl)methyl]-2-oxotetrahydrofuran-3-yl}methyl , - D -glucopyranoside (2), have been isolated from the roots of Urtica fissa E. Pritz. Their structures were determined based on spectroscopic methods (HR-MS, 1D- and 2D-NMR, HMBC, HSQC, and NOESY). [source] Three New Lanostane Triterpenoids, Inonotsutriols A, B, and C, from Inonotus obliquusHELVETICA CHIMICA ACTA, Issue 8 2008Sayaka Taji Abstract Three new lanostane-type triterpenoids, inonotsutriols A (1), B (2), and C (3) were isolated from the sclerotia of Inonotus obliquus (Pers.: Fr.) (Japanese name: kabanoanatake; Russian name: chaga). Their structures were determined to be (3,,21R,24S)-21,24-cyclolanost-8-ene-3,21,25-triol (1), (3,,21R,24R)-21,24-cyclolanost-8-ene-3,21,25-triol (2), and (3,,21R,24S)-21,24-cyclolanosta-7,9(11)-diene-3,21,25-triol (3) on the basis of NMR spectroscopy including 1D and 2D experiments (1H,1H-COSY, NOESY, HMQC, and HMBC) and EI-MS. [source] New Sesquiterpenoids from Ligularia duciformisHELVETICA CHIMICA ACTA, Issue 6 2008Wen-Shu Wang Abstract From the whole plants of Ligularia duciformis, four new sesquiterpenoids, 3, -acetoxy-6, -methoxyeremophila-7(11),9(10)-dien-12,8, -olide (1), 3, -acetoxy-8, -hydroxy-6, -methoxyeremophila-7(11),9(10)-dien-12,8, -olide (2), 3, -acetoxy-10, -hydroxy-6,,8, -dimethoxyeremophil-7(11)-en-12,8, -olide (3), and 3, -acetoxy-6,,8,,10, -trihydroxyeremophil-7(11)-en-12,8, -olide (4) were isolated. Their structures were established by high-field NMR techniques (1H,1H-COSY, 13C-APT, HMQC, HMBC, and NOESY) and HR-ESI-MS analysis, together with comparison of the spectroscopic data with those of structurally related compounds. In addition, the cytotoxicity of the new compounds against human hepatic cancer cells Bel-7402, human pneumonic cancer cells A-549, and human colonic cancer cells HCT-8 were evaluated, the new compounds showed no cytotoxicity against the three tumor cells (all IC50 values >200,,M). [source] Triterpene Esters Isolated from Leaves of Maytenus salicifoliaReissekHELVETICA CHIMICA ACTA, Issue 4 2007Miranda, Rodrigues, Roqueline, Silva de Abstract The triterpene ester (3,)-olean-18-en-3-yl stearate (1), together with (3,)-urs-12-en-3-yl stearate (2), and (3,)-lup-20(29)-en-3-yl stearate (3) were isolated from leaves of Maytenus salicifoliaReissek (Celastraceae). The structure of 1, a new compound, including its configuration, was established by 1H, 13C, and DEPT-135 NMR data, including 2D experiments (HSQC, HMBC, COSY, and NOESY). The molecular mass (692 Da) was confirmed by gas chromatography coupled with mass spectrometry (CG/MS). [source] The Stereostructure of Porphyra-334: An Experimental and Calculational NMR Investigation.HELVETICA CHIMICA ACTA, Issue 3 2007Evidence for an Efficient, Proton Sponge' Abstract The mycosporine-like amino acid (MAA) porphyra-334 (1) is subjected to extensive 1H- and 13C-NMR analysis as well as to density-functional-theory (DFT) calculations. All 1H- and 13C-NMR signals of 1 are assigned, as well as the resonances of prochiral proton pairs. This is achieved by 500-MHz standard COSY, HMQC, and HMBC experiments, as well as by one-dimensional (DPFGSE-NOE) and two-dimensional (NOESY) NOE experiments. Diffusion measurements (DOSY) confirm that 1 is monomeric in D2O solution. DFT Calculations yield 13C-NMR chemical shifts which are in good agreement for species 6 which is the imino N-protonated form of 1. An exceptionally high proton affinity of 265.7,kcal/mol is calculated for 1, indicating that 1 may behave as a very powerful ,proton sponge' of comparable strength as synthetic systems studied so far. Predictions of 13C-NMR chemical shifts by the ,NMRPredict' software are in agreement with the DFT data. The absolute configuration at the ring stereogenic center of 1 is concluded to be (S) from NOE data as well as from similarities with the absolute configuration (S) found in mycosporine-glycine 16. This supports the assumption that 1 is biochemically derived from 3,3- O -didehydroquinic acid (17). The data obtained question the results recently published by a different research group claiming that the configuration at the imino moiety of 1 is (Z), rather than (E) as established by the here presented study. [source] Semiautomatic sequence-specific assignment of proteins based on the tertiary structure,The program st2nmrJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 3 2002Primo, Pristov Abstract The sequence-specific assignment of resonances is still the most time-consuming procedure that is necessary as the first step in high-resolution NMR studies of proteins. In many cases a reliable three-dimensional (3D) structure of the protein is available, for example, from X-ray spectroscopy or homology modeling. Here we introduce the st2nmr program that uses the 3D structure and Nuclear Overhauser Effect spectroscopy (NOESY) peak list(s) to evaluate and optimize trial sequence-specific assignments of spin systems derived from correlation spectra to residues of the protein. A distance-dependent target function that scores trial assignments based on the presence of expected NOESY crosspeaks is optimized in a Monte Carlo fashion. The performance of the program st2nmr is tested on real NMR data of an ,-helical (cytochrome c) and ,-sheet (lipocalin) protein using homology models and/or X-ray structures; it succeeded in completely reproducing the correct sequence-specific assignments in most cases using 2D and/or 15N/13C Nuclear Overhauser Effect (NOE) data. Additionally to amino acid residues the program can also handle ligands that are bound to the protein, such as heme, and can be used as a complementary tool to fully automated assignment procedures. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 335,340, 2002 [source] Synthesis and structure of some imines containing furoxan ring derived from isosafroleJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 6 2004Nguyen Huu Dinh A series of 14 imines containing furoxan and benzene rings has been prepared starting from isosafrole. The structure of reported compounds have been confirmed by elemental analysis, EI MS, UV, IR, and NMR spectroscopy. It is shown that, on treatment with Na2S2O4, the nitro group on the benzene ring was reduced to amino group, but the N,O group of the furoxan ring was not. The 1H- and 13C NMR signals are assigned based on their spin-spin splitting patterns, in some cases, NOESY and HMBC spectra are used. The NOESY spectra indicate that for reported imines, the benzene and the furoxan rings could not be co-planar; the imine group has E -configuration. [source] Purification and identification of an impurity in bulk hydrochlorothiazideJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2001Xueguang Fang Abstract Hydrochlorothiazide (6-chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide) (HCTZ) 1 is a widely used diuretic and anti-hypertensive. Recently, the Pharmeuropa recognized a new impurity initially thought to be an HCTZ dimer 6, which consists of the active drug (HCTZ) linked via the former ,-ring methylene to a known degradate, 5-chloro-2,4-disulfamylaniline 2. In an effort to meet a new requirement, an analytical high-pressure liquid chromatography method was developed that was selective and sensitive to the subject impurity. The impurity was concentrated and purified using a combination of solid phase extraction and reverse-phase high-pressure liquid chromatography. Subsequently, the impurity has been identified as a specific HCTZ-CH2 -HCTZ isomer utilizing a variety of analytical techniques, including hydrolysis, ultraviolet spectroscopy, liquid chromatography/mass spectrometry, and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The data resulting from the application of these analytical techniques confirm the identity of the impurity as a methylene bridged pair of HCTZ molecules; however, a total of six possible isomers 7a,f exist because of the presence of three reactive amines/sulfonamides on each HCTZ molecule. One unique molecular structure (4-[{6-chloro-3,4,-dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide-1,1-dioxide}-methyl]-chloro-3-hydro-H-1,2,4-benzothiadiazine-7-sulfonamide-1,1-dioxide) 7f was identified using two-dimensional COSY, NOESY, and TOCSY 1H NMR experiments. © 2001 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90:1800,1809, 2001 [source] 1H and 13C NMR conformational study of 2-(benzotriazol-1-yl)-substituted tetrahydrofuransJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 3 2003Alan R. Katritzky Abstract Assignments of the proton and carbon NMR signals for 2-(benzotriazol-1-yl)tetrahydrofurans 1,6 are based on 1H,1H COSY, NOESY, 1H,13C heteronuclear HETCOR, 1H,13C heteronuclear long-range HETCOR-LR and nuclear Overhauser enhancement experiments, and supported by selective spin decoupling experiments. The electronic and steric effects of the 2-benzotriazolyl substituent on the 1H and 13C NMR chemical shifts are evaluated and discussed. Conformational isomers cis and trans are distinguished by the magnitude of the J(H,2,H,3) coupling constant, by one-bond 1J(C,2, H,2) coupling constants and by 13C chemical shifts of the C-2 anomeric carbon. The benzotriazol-1-yl group prefers the pseudo-axial orientation in each of 1,6. The stereochemistry and conformation of 6 are rigorously demonstrated by an x-ray structure. Copyright © 2003 John Wiley & Sons, Ltd. [source] Probing the solvation shell of organic molecules by intermolecular 1H NOESY,JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 12 2002Alessandro Bagno Abstract The solvation of some neutral and charged organic molecules (phenol, nitroanilines, tetraalkylammonium) in binary solvent mixtures was investigated by means of intermolecular 1H-NOESY NMR spectroscopy. The solvation shell of the solute is, in most cases, selectively enriched in one of the cosolvents (preferential solvation). The origin of preferential solvation is discussed in terms of solute,solvent interactions and microheterogeneity in the solvent mixture. Copyright © 2002 John Wiley & Sons, Ltd. [source] 1H and 13C NMR study of a series of C-9-substituted 19-norsteroidsJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 1 2002Laurence Dallery Abstract The 1H and 13C NMR spectra of a series of 9-substituted 19-norsteroids were completely assigned using a series of 2D NMR experiments, which included 1H,1H COSY, NOESY and 1H,13C heteronuclear HETCOR and HMQC. For second-order spin systems, chemical shifts and coupling constants were obtained by simulation of the experimental spectrum. Criteria were deduced to characterize the stereochemistry of these different compounds (multiplet pattern of H-8, and variation of chemical shifts). The results allow the easy determination of the configuration at C-9. Conformational changes resulting from the substitution were studied by NMR and molecular modeling calculations (AM1). Copyright © 2001 John Wiley & Sons, Ltd. [source] A hyperbranched, rotaxane-type mechanically interlocked polymerJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2010Shijun Li Abstract Based on the dibenzo-24-crown-8/1,2-bis(pyridinium)ethane recognition motif, a hyperbranched mechanically interlocked polymer was prepared by polyesterification of an easily available dynamic trifunctional AB2 pseudorotaxane monomer. It was characterized by various techniques including 1H NMR, COSY, NOESY, GPC, viscosity, TGA, dynamic laser light scattering, AFM, and SEM. Its GPC Mn was determined to be 191 kDa with polydispersity 1.7 and its hydrodynamic diameter in a dilute solution in acetone was about 70 nm. This measured Mn value corresponds to about 93 repeating units. The study reported here presents not only a new polymer topology but also a novel and convenient way to prepare mechanically interlocked polymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4067,4073, 2010 [source] Structure elucidation and NMR assignments of two unusual monoterpene indole alkaloids from Psychotria stachyoidesMAGNETIC RESONANCE IN CHEMISTRY, Issue 9 2010Antonia Torres Ávila Pimenta Abstract Two unusual monoterpene indole alkaloids, stachyoside (1) and nor-methyl-23-oxo-correantoside (2), have been isolated from the aerial parts of Psychotria stachyoides. The structural elucidation of both compounds was performed by the aid of HRESIMS, FT-IR, and 1D- and 2D-NMR techniques including COSY, HSQC, HMBC, and NOESY. Copyright © 2010 John Wiley & Sons, Ltd. [source] Acylated manoyl oxide diterpenes of Stemodia trifoliataMAGNETIC RESONANCE IN CHEMISTRY, Issue 6 2010Wildson Max B. da Silva Abstract Two new labdane diterpenes, 6,-malonyloxy-ethyl ester manoyl oxide and bis-6,-dioxymanoylmalonate, together with the known 6,-hydroxymanoyl oxide, 6,-malonyloxymaloyl oxide and betulinic acid were isolated from leaves of Stemodia trifoliata. Their structures were elucidated by spectroscopic studies (IR and HR-ESI-MS), including an extensive NMR (COSY, HSQC, HMBC and NOESY) analysis. Copyright © 2010 John Wiley & Sons, Ltd. [source] 1H and 13C NMR assignments for two new steroids from the coral Chromonephthea sp.MAGNETIC RESONANCE IN CHEMISTRY, Issue 4 2009Hua-Wei Geng Abstract Two new steroids isolated from EtOH extracts of the South China Sea soft coral Chromonephthea sp. were identified. One-dimensional (1D) and two-dimensional (2D) NMR experiments including COSY, HSQC, HMBC and NOESY were used for the determination of their structure. Copyright © 2008 John Wiley & Sons, Ltd. [source] Complete assignment of 1H and 13C NMR data of pravastatin derivativesMAGNETIC RESONANCE IN CHEMISTRY, Issue 1 2009Markus Bacher Abstract The complete 1H and 13C NMR data of 27 pravastatin derivatives are presented. Assignment was achieved by use of 1D and 2D NMR experiments (selective 1D NOE, COSY, NOESY, HSQC, HMBC). Copyright © 2008 John Wiley & Sons, Ltd. [source] Structural elucidation of four new furostanol saponins from Tupistra chinensis by 1D and 2D NMR spectroscopyMAGNETIC RESONANCE IN CHEMISTRY, Issue 1 2009Kun Zou Abstract Four new furostanol saponins (1,4), two pairs of diastereoisomers, were isolated from methanolic extracts of Tupistra chinensis rhizomes and their structures were assigned from 1H and 13C NMR spectra, DEPT, and by 2D COSY, NOESY, HMQC, and HMBC experiments. Copyright © 2008 John Wiley & Sons, Ltd. [source] NMR elucidation of a novel (S)-pentacyclo-undecane bis-(4-phenyloxazoline) ligand and related derivativesMAGNETIC RESONANCE IN CHEMISTRY, Issue 12 2008Grant A. Boyle Abstract The NMR elucidation of a novel ligand (S)-pentacyclo-undecane bis-(4-phenyloxazoline) and related pentacyclo-undecane (PCU) derivatives is reported. Two-dimensional NMR proved to be a powerful technique in overcoming the difficulties associated with the elucidation of these compounds when only one-dimensional NMR data is utilized. A chiral substituent was introduced to both ,arms' of the PCU skeleton to produce derivatives 1,3. These derivatives display C1 symmetry with all thecage atoms being nonequivalent. Owing to overlapping of peaks in the 1H spectra, identification of these diastereomeric protons was very difficult. The 13C spectra gave rise to clear splitting of the nonequivalent carbons. This is unusual compared to similar PCU derivatives with chiral substituents as splitting of all the diastereomeric cage carbons has not yet been reported. Nuclear Overhauser enhancement spectroscopy (NOESY) correlations of derivatives 1,3 confirm the different conformations of the molecule in which the side ,arms' occupy different orientations with respect to cage moiety. Copyright © 2008 John Wiley & Sons, Ltd. [source] Conformational properties of the macrocyclic trichothecene mycotoxin verrucarin A in solutionMAGNETIC RESONANCE IN CHEMISTRY, Issue 12 2008Georgia Fragaki Abstract Phase-sensitive nuclear Overhauser enhancement spectroscopy (NOESY) experiments, 3J couplings and computational molecular modeling (MM2* and MMFF force fields) were employed to examine the conformational properties of verrucarin A in chloroform solutions. The MMFF force field calculations resulted in a family of 12 low-energy structures along with their populations, the latter being determined by the NMR analysis of molecular flexibility in solution(NAMFIS) deconvolution analysis. The concluded model was capable of reproducing successfully the experimental NOESY cross-peak volumes and the proton-coupling constants. Among the 12 conformers, the one which was similar to the structure of verrucarin A in the solid state was the predominant accounting for 75% of the total relative population, although other low-energy conformations contributed to a lesser degree in order to explain the experimental data. Copyright © 2008 John Wiley & Sons, Ltd. [source] 1H and 13C NMR assignments for new heterocyclic TAM leuco dyes, (2Z,2,E)-2,2,-(2-phenyl propane-1,3-diylidene) bis(1,3,3-trimethylindoline) derivatives.MAGNETIC RESONANCE IN CHEMISTRY, Issue 9 2008Part II Abstract The 1H and 13C NMR spectra of the novel heterocyclic Leuco-TAM dyes, (2Z, 2,E)-2,2,-(2-phenyl propane-1,3-diylidene) bis(1,3,3-trimethylindoline) derivatives 1,4 as precursors of triarylmethane (TAM)+ (Malachite Green FB-analog) dyes were completely assigned by 1D and 2D NMR experiments, including DEPT, COSY, HSQC, HMBC, and NOESY. Especially, the diastereotopic gem -dimethyl protons at the C3 and C3, positions of the FB rings were definitively assigned. The (Z,E) isomers adopt the energetically favored three-bladed propeller conformation in solution. Copyright © 2008 John Wiley & Sons, Ltd. [source] Five new bidesmoside triterpenoid saponins from Stauntonia chinensisMAGNETIC RESONANCE IN CHEMISTRY, Issue 7 2008Gao Hao Abstract Eleven triterpenoid saponins (1,11) were isolated from Stauntonia chinensis DC. (Lardizabalaceae), including five new compounds, yemuoside YM21,25 (1,3, 6, 7) structures of which were elucidated by chemical methods and a combination of MS, 1D- and 2D- NMR experiments including DEPT, 1H1H COSY, HSQC, HMBC, TOCSY, and NOESY as 3- O -,- L -arabinopyranosyl-(1 , 3)-[,- L -rhamnopyranosyl-(1 , 2)-],- L -arabinopyranosyl-akebonicacid-28- O -,- L -rhamnopyranosyl-(1 , 4)-,- D -glucopyranosyl-(1 , 6)-,- D -glucopyranosyl ester (1), 3- O -,- D -xylopyranosyl-(1 , 3)-,- L -rhamnopyranosyl-(1 , 2)-,- L -arabinopyranosyl-akebonic acid-28- O -,- L -rhamnopyranosyl-(1 , 4)-,- D -glucopyranosyl-(1 , 6)-,- D -glucopyranosyl ester (2), 3- O -,- D -glucopyranosyl-(1 , 3)-,- L -arabinopyranosyl-akebonic acid-28- O -,- L -rhamnopyranosyl-(1 , 4)-,- D -glucopyranosyl-(1 , 6)-,- D -glucopyranosyl ester (3), 3- O -,- L -arabinopyranosyl-(1 , 3)-[,- L -rhamnopyranosyl-(1 , 2)-],- L -arabinopyranosyl-akebonic cid-28- O -,- D -glucopyranosyl-(1 , 6)-,- D -glucopyranosyl ester (6), 3- O -,- L -arabinopyranosyl-(1 , 3)-[,- L -arabinopyranosyl-(1 , 2)-],- L -arabinopyranosyl-akebonic acid-28- O -,- D -glucopyranosyl-(1 , 6)-,- D -glucopyranosyl ester (7). Copyright © 2008 John Wiley & Sons, Ltd. [source] Complete 1H and 13C NMR assignments and Z/E-stereoconfiguration determination of isomers of 1,4-diketone derivativesMAGNETIC RESONANCE IN CHEMISTRY, Issue 1 2008Guohua Xu Abstract Complete 1H and 13C NMR assignments and Z/E-stereoconfiguration determination for a series of new isomers of 1,4-diketone derivatives obtained via self-sorting tandem reaction were accomplished by means of one- and two-dimentional NMR experiments including 1H, 13C, gCOSY, gHSQC, gHMBC, and NOESY. Copyright © 2008 John Wiley & Sons, Ltd. [source] Secondary metabolites from Paronychia argenteaMAGNETIC RESONANCE IN CHEMISTRY, Issue 1 2008Alessandra Braca Abstract Two new oleanane saponins (1 and 2) and one new flavonol glycoside (3) together with six known flavonoids, were isolated from the aerial parts of Paronychia argentea. Their structures were elucidated by 1D and 2D NMR experiments including 1D-TOCSY, DQF-COSY, NOESY, HSQC, and HMBC spectroscopy, as well as ESI-MS analysis. Copyright © 2007 John Wiley & Sons, Ltd. [source] 3-Oxo-12,-hydroxyfriedelane from Maytenus gonoclada: structure elucidation by 1H and 13C chemical shift assignments and 2D-NMR spectroscopyMAGNETIC RESONANCE IN CHEMISTRY, Issue 10 2007Mauro Lúcio G. Oliveira Abstract The compounds 3-oxofriedelane (1), 3,-hydroxyfriedelane (2), 3,11-dioxofriedelane (3), 3,16-dioxofrie delane (4) and 3-oxo-12,-hydroxyfriedelane (5) were isolated from the hexane extract of Maytenus gonoclada Mart. (Celastraceae) leaves. Structural formula and the stereochemistry of the new pentacyclic triterpene 3-oxo-12,-hydroxyfriedelane (5) were established through 1H and 13C NMR and DEPT 135 spectral data including 2D experiments (HMBC, HMQC, COSY, and NOESY) and mass spectrometry (GC-MS). Copyright © 2007 John Wiley & Sons, Ltd. [source] Structural determination of kochiosides A,C, new steroidal glucosides from Kochia prostrata, by 1D and 2D NMR spectroscopyMAGNETIC RESONANCE IN CHEMISTRY, Issue 9 2007Muhammad Imran Abstract Kochiosides A,C, three new steroidal glucosides, have been isolated from the ethyl acetate fraction of Kochia prostrata and their structures assigned from its 1H and 13C NMR spectra, DEPT and by 2D COSY, NOESY, HMQC and HMBC experiments. Copyright © 2007 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||||||||||||||