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1.
Atricins A (1) and B (2), two new oleanane-type triterpenes have been isolated from the chloroform-soluble fractions of Perovskia atriplicifolia and their structures assigned from (1)H and (13)C-NMR spectra, Distortion Enhancement by Polarization Trasfer (DEPT) and by 2D-COSY, HMQC, Nuclear Overhauser Enhancement Spectroscopy (NOESY) and Hetronuclear mutiple-bond correlation (HMBC) experiments. 相似文献
2.
Silymins A (1) and B (2), the new pentacyclic triterpenes, have been isolated from ethyl acetate fraction of Silybum marianum and their structures assigned from 1H and 13C NMR spectra, DEPT and by 2D COSY, NOE and HMBC experiments. 相似文献
3.
Muhammad Imran Muhammad Ibrahim Naheed Riaz Prof. Dr. Abdul Malik 《Magnetic resonance in chemistry : MRC》2009,47(6):532-536
Aervins A‐D (1‐4), four new coumaronochromone analogues have been isolated from the CHCl3‐soluble fraction of the MeOH extract of the whole plant of Aerva persica. Their structures were assigned based on 1H NMR, 13C NMR spectra, DEPT, and by 2DNMR experiments. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
4.
Ahmad Z Mehmood S Fatima I Malik A Ifzal R Afza N Iqbal L Latif M Nizami TA 《Magnetic resonance in chemistry : MRC》2008,46(1):94-98
Salsolins A (1) and B (2), the new triterpenes, have been isolated from the chloroform soluble fraction of Salsola baryosma along with 2alpha,3beta,23,24-tetrahydroxyurs-12-en-28-oic acid (3) reported for the first time from this species. Their structures have been assigned from 1H and 13C NMR spectra, DEPT and by 2D COSY, NOESY, HMQC and HMBC experiments. The compounds 1-3 showed significant antioxidant activity. 相似文献
5.
Structural determination of kochiosides A-C, new steroidal glucosides from Kochia prostrata, by 1D and 2D NMR spectroscopy 总被引:1,自引:0,他引:1
Kochiosides A-C, three new steroidal glucosides, have been isolated from the ethyl acetate fraction of Kochia prostrata and their structures assigned from its (1)H and (13)C NMR spectra, DEPT and by 2D COSY, NOESY, HMQC and HMBC experiments. 相似文献
6.
单猪屎豆碱的2D NMR 总被引:2,自引:0,他引:2
H、13C和DEPT及2DNMR(gCOSY、NOESY、gHSQC和gHMBC)方法,进一步对单猪屎豆碱的核磁共振谱进行了全归属。 相似文献
7.
Azhar Mahmood Itrat Fatima Shaheen Kosar Rehana Ahmed Abdul Malik 《Magnetic resonance in chemistry : MRC》2010,48(2):151-154
Prunusins A (1) and B (2), the new C‐alkylated flavonoids, have been isolated from the seed kernels of Prunus domestica. Their structures were assigned from 1H and 13C nuclear magnetic resonating spectra, DEPT and by correlation spectroscopy, HMQC and HMBC experiments. 3, 5, 7, 4′‐Tetrahydroxyflavone (3) and 3, 5, 7‐trihydroxy‐8, 4′‐dimethoxyflavone (4) have also been reported from this species. Both compounds (1) and (2) showed significant antifungal activity against pathogenic fungus Trichophyton simmi. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
8.
Bakhat Ali Muhammad Imran Riaz Hussain Zaheer Ahmed Abdul Malik 《Magnetic resonance in chemistry : MRC》2010,48(2):159-163
Two new flavonoids, abutilin A and B, were isolated from the chloroform soluble fraction of Abutilon pakistanicum and their structures assigned from 1H and 13C NMR spectra, DEPT and by 2D COSY, HMQC and HMBC experiments. Ferulic acid (3), (E)‐cinnamic acid (4), 5‐hydroxy‐4′,6,7,8‐tetramethoxyflavone (5), kaempferol (6), luteolin (7) and luteolin 7‐O‐β‐D ‐glucopyranoside (8) have also been reported from this species. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
9.
Compounds 1-7 form a novel group of dithiocarbamates, first synthesized from the reaction of a series of primary amines with carbon disulfide and 3-bromo ethyl pyruvate in the presence of anhydrous potassium phosphate. Structure elucidation of this group of compounds was accomplished using extensive 1D and 2D NMR spectroscopic studies, including (1)H, (13)C, COSY, NOESY, HSQC, and gHMBC experiments. The distinction between the linear structures I, II and the cyclic structure III was made mainly on the basis of the analysis of the cross peak between H-2 and H-4a in the COSY spectra, in combination with the long-range correlation between H-2 and C-4, 6 in the gHMBC spectra. 相似文献
10.
Regioselective synthesis of 2-[1-(2-oxo-2-phenylethyl)-1H-[1,2,3]triazol-4-ylmethoxy]-benzaldehyde derivatives was achieved by [3 + 2] cycloaddition reaction of 2-(prop)-2-ynyloxy-benzaldehyde derivatives with phenacyl azide. The regiochemistry and the spectral assignments of the synthesized triazole derivatives were studied using both 1D and 2D NMR spectral techniques in solution. 相似文献
11.
《Magnetic resonance in chemistry : MRC》2003,41(2):145-146
A new prenylated benzopyrancarboxylic acid, 1a (3,4‐dihydro‐5‐hydroxy‐2,7‐dimethyl‐8‐(2‐methyl‐2‐butenyl)‐ 2‐(4‐methyl‐1, 3‐pentadienyl)‐2H‐1‐benzopyran‐6‐carboxylic acid) was isolated from Peperomia amplexicaulis and fully characterized by 1D and 2D NMR and high‐resolution mass spectrometry. In the course of this investigation, the structure of a related compound (minus the carboxylic acid group) which was previously assigned as 2b was corrected to structure 1b . Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
12.
Trifunović S Milosavljević S Vajs V Macura S Todorović N 《Magnetic resonance in chemistry : MRC》2008,46(5):427-431
From detailed study of 1D and 2D NMR spectra of ten natural 1,2-epoxyguaianolides (bis-1,2:3,4-epoxyguaianolides and guaianolide-1,2-epoxychlorohydrins), we identified general spectral traits helpful for stereochemical assignment of such sesquiterpene lactones. We found that the chemical shifts of certain (1)H and (13)C nuclei are consistently dependent on the configuration of 1,2-epoxy-ring which could be used as a simple rule for establishing this configuration. Then, from 1D and 2D (COSY, NOESY, HMQC, HMBC) NMR data, applying the observed rule, the structure and stereochemistry of two new, diastereomeric guaianolide-1,2-epoxychlorohydrins, isolated from Achillea serbica, are determined. The NMR data, namely, nuclear overhauser enhancement (NOE) correlations, pointed out two conformations of guaianolide's cycloheptane ring. The semiempirical calculations (AM1 and PM3 methods), performed in order to gain additional information regarding conformations, resulted in three geometries of investigated lactones. Even so, the conformations derived from the NMR data agreed well with those calculated by semiempirical methods. 相似文献
13.
Muhammad Saleem Naseem Akhter Muhammad Shaiq Ali Mamona Nazir Naheed Riaz Muhammad Moazzam Muhammad Arshad Abdul Jabbar 《Magnetic resonance in chemistry : MRC》2009,47(3):263-265
Chromatographic analysis of the alcoholic extract from Salsola imbricata yielded two new secondary metabolites, salisomide (1) and salisoflavan (2). Their structures were established with the help of spectroscopic techniques including COSY, HMQC and HMBC NMR experiments. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
14.
Kun Zou Jun‐zhi Wang Zhi‐yong Guo Ming Du Jun Wu Yuan Zhou Fei‐jun Dan Chuang Liu 《Magnetic resonance in chemistry : MRC》2009,47(1):87-91
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. 相似文献
15.
Fazuo Wang Tianjiao Zhu Min Zhang Aiqun Lin Weiming Zhu Qianqun Gu 《Magnetic resonance in chemistry : MRC》2010,48(2):155-158
Three new furan and pyran derivatives named aspericins A? C (1–3), as well as a known asperic acid (4), have been isolated from the marine‐derived fungus Rhizopus sp. 2‐PDA‐61. The complete 1H and 13C NMR assignments for the new compounds were carried out using 1H, 13C, DEPT, COSY, HMQC, HMBC, and NOESY NMR experiments. Compounds 1–3 were evaluated for their cytotoxic activities on P388, A549, HL‐60, and BEL‐7420 cell lines by the MTT and SRB methods. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
16.
《Magnetic resonance in chemistry : MRC》2003,41(4):246-252
The solution conformations of the novel estrogen receptor ligands (17α,20E)‐(p‐trifluoromethylphenyl)vinylestradiol ( 1 ) and (17α,20E)‐(o‐trifluoromethylphenyl)vinylestradiol ( 2 ) were investigated in 2D and 1D NOESY studies and by comparison of 13C NMR chemical shifts with theoretical shieldings. The 1H and 13C assignments of 1 and 2 were determined by DEPT, COSY and HMQC experiments. The conformations of the 17α‐phenylvinyl substituents of 1 and 2 are of interest because of their differing receptor binding affinities and effects in in vivo uterotrophic growth assays. A statistical method of evaluating contributing conformers of 1 and 2 from predicted 13C shifts of possible structures correlated fairly well with conformational conclusions derived from the NOE data. The 17α substituents of 1 and 2 apparently exist in similar conformational equilibria, suggesting that while 1 and 2 would occupy a similar receptor volume, interactions with the protein may shift the equilibrium and thereby influence the expression of the ligand. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
17.
Xiongming Luo Shuhua Qi Hao Yin Zhihui Xiao Si Zhang 《Magnetic resonance in chemistry : MRC》2009,47(12):1110-1114
Four new coumarins, micromelosides A–D, together with four known coumarins were isolated from the stem bark of Micromelum falcatum. The complete assignments of the 1H and 13C NMR chemical shifts for these new compounds were achieved by means of 1D and 2D NMR techniques, including 1H‐1H COSY, HSQC, HMBC and NOE difference. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
18.
A procedure for the estimation of the mixing time between the last two 90° pulses in the classic three-pulse sequence NOESY/EXSY is proposed and tested and some considerations for the treatment of the two-dimensional (2D) 1H NMR exchange spectra are given. The rate constants are thus obtained with reasonable precision. This procedure was followed to obtain the 2D spectra of the model compound α-[bis(dimethylamino)methylene]-4-nitrophenylacetonitrile, which represents a four-site exchange system. The barriers to restricted rotations found in this compound were also determined from one-dimensional (1D) 1H NMR spectra, which were processed with the iterative complete lineshape analysis (CLSA) method. The double-fit approach was incorporated in the CLSA method. It is shown that the results from the 2D dynamic NMR spectral studies corroborate those obtained by the CLSA double-fit method. 相似文献
19.
Guo Z Shao C She Z Cai X Liu F Vrijimoed LL Lin Y 《Magnetic resonance in chemistry : MRC》2007,45(5):439-441
The complete (1)H and (13)C NMR assignments are reported for the novel natural product Bacillosporin D together with the known compound Bacillosporin C. These compounds containing seven rings were isolated from the mangrove endophytic fungus SBE-14 from the South China Sea. 1D and 2D NMR experiments, including COSY, HMQC and HMBC were used to the determination of the structures and NMR assignments. It is proposed that 1 was biogenetically produced by transforming 2. Transforming a lactone to an anhydride is unusual in nature. 相似文献