共查询到20条相似文献,搜索用时 15 毫秒
1.
Maria Conceição M. Torres José Gustavo L. Almeida Raimundo Braz‐Filho Edilberto R. Silveira Otília Deusdênia L. Pessoa 《Magnetic resonance in chemistry : MRC》2012,50(1):74-78
From the leaves of Solanum campaniforme, two new spirosolane alkaloids β‐acetoxyl‐(25S)‐22βN‐spirosol‐4‐en‐3‐one (1) and β‐hydroxyl‐(25S)‐22βN‐spirosol‐4‐en‐3‐one (4) were isolated along with two other known alkaloids of the same class (25S)‐22βN‐spirosol‐1,4‐dien‐3‐one (2) and (25S)‐22βN‐spirosol‐4‐en‐3‐one (3), which are reported for the first time as natural products. The structures of all alkaloids were established after an extensive analysis by 1D and 2D NMR spectroscopy (COSY, HSQC, HMBC and NOESY) as well as HRESIMS. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
2.
Chen Y Shao C Huang Z Zhang Y Cai X She Z Zhou S Lin Y 《Magnetic resonance in chemistry : MRC》2009,47(1):92-95
The structure elucidations and complete (1)H and (13)C NMR assignments are reported for two new natural products: 3-benzylidene-8,8a-dihydroxy-2-methyl-hexahydro-pyrrolo[1,2-a]pyrazine-1,4-dione(1) and 4-hydroxy-6-(hydroxy-phenyl-methyl)-N-(3-methyl-butyryl)-nicotinamide (2). Both of these secondary metabolites were isolated from the fermentation medium of a Mangrove endophytic fungus. High resolution electron impact mass spectrometry (HREIMS), FT-IR Spectroscopy and NMR experiments including gCOSY, gHMQC, gHMBC and NOE were used for determination of the structures and assignments of the amide alkaloids. 相似文献
3.
Wei Li Shisheng Wang Jiatao Feng Yuansheng Xiao Xingya Xue Hui Zhang Yaqin Wang Xinmiao Liang 《Magnetic resonance in chemistry : MRC》2009,47(10):902-908
Thirteen curcuminoids (1–13) were isolated from the rhizomes of Curcuma longa. Among them, 1,5‐dihydroxy‐1,7‐bis(4‐hydroxyphenyl)‐4,6‐heptadiene‐3‐one (1), 1,5‐dihydroxy‐1‐(4‐hydroxy‐3‐methoxyphenyl)‐7‐(4‐hydroxyphenyl)‐4,6‐heptadiene‐3‐one (2), 1,5‐dihydroxy‐1‐(4‐hydroxyphenyl)‐7‐(4‐hydroxy‐3‐methoxyphenyl)‐4,6‐heptadiene‐3‐one (3), and 3‐hydroxy‐1,7‐bis‐(4‐hydroxyphenyl)‐6‐heptene‐1,5‐dione (4) are new compounds, and 1‐(4‐hydroxyphenyl)‐7‐(3, 4‐dihydroxyphenyl)‐1, 6‐heptadiene‐3, 5‐dione (5) is isolated from natural sources for the first time. The structures of these compounds were elucidated by extensive spectroscopic analyses, especially 1D and 2D NMR spectroscopy. The 13C NMR data and complete 1H and 13C NMR assignments of some known compounds are reported for the first time. In addition, the errors of 1H and 13C assignments reported in the literature were corrected. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
4.
Alexsandro Fernandes Marinho Eduardo de Jesus Oliveira Josean Fechine Tavares Raimundo Braz Filho Jose Maria Barbosa‐Filho 《Magnetic resonance in chemistry : MRC》2013,51(5):312-315
des‐7′‐O‐methylroraimine (compound 1) and epi‐des‐7′‐O‐methylroraimine (compound 2), two new isomeric bisbenzylisoquinoline alkaloids were isolated and characterized as a mixture from the rhizomes of Cissampelos sympodialis Eichl. The unambiguous structural elucidation of both isomers was performed with the aid of HR‐ESI‐MS, FT‐IR, and NMR techniques including COSY, HMQC, HMBC, and NOESY. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
5.
Two new unusual xanthones, 5‐O‐β‐d ‐glucopyranosyl‐1,3,8‐trihydroxy‐5,6,7,8‐tetrahydroxanthone (1) and 1,3,5,8‐tetrahydroxy‐5,6,7,8‐tetrahydroxanthone (2), were isolated from Lomatogonium carinthiacum (Wulf) Reichb. Their structures were elucidated on the basis of spectroscopic methods including UV, IR, ESI‐MS, 1D NMR, and 2D NMR. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
6.
Zhongjing Huang Ruiyun Yang Xianhong Yin Zhigang She Yongcheng Lin 《Magnetic resonance in chemistry : MRC》2010,48(1):80-82
The structure elucidations and complete 1H and 13C NMR assignments are reported for two new xanthone derivatives: 1,7‐dihydroxy‐2‐methoxy‐3‐(3‐methylbut‐2‐enyl)‐9H‐xanthen‐9‐one (1) and 1‐hydroxy‐4,7‐dimethoxy‐6‐(3‐oxobutyl)‐9H‐xanthen‐9‐one (2). Both of these secondary metabolites were isolated from the fermentation medium of a mangrove endophytic fungus (No. ZH19). High‐resolution electron impact mass spectrometry (HREIMS), Fourier transform infrared (FT‐IR) absorption spectrometry, and NMR experiments including gCOSY, gHMQC, and gHMBC were used for the determination of the structures and NMR spectral assignments. Preliminary pharmacological test showed that compounds (1) and (2) inhibited KB cells with IC50 values of 20 and 35 µmol/ml, and KBV200 cells with IC50 values of 30 and 41 µmol/ml, respectively. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
7.
Denise Aline Casimiro Bezerra Josean Fechine Tavares Paula Ferreira dos Santos Marianna Vieira Sobral Castello Branco Maria de Fátima Agra Fernanda Lima Subrinho Raimundo Braz‐Filho Marcelo Sobral da Silva 《Magnetic resonance in chemistry : MRC》2013,51(8):497-499
A new pyrrolizidine alkaloid, named crotavitelin, was isolated from fruits of Crotalaria vitellina, Fabaceae (Papilionoideae). The structure was established by spectroscopic techniques such as one‐dimensional and two‐dimensional NMR, IR, and MS. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
8.
Two new saponins were isolated from leaves of Panax quinquefolium and their structures were elucidated as 3beta, 12beta, 20S-trihydroxy-25-methoxydammar-23-ene 3-O-{[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-20-O-[alpha-L-arabinopyranosyl(1-->6)]-beta-D-glucopyranoside (1) and 3beta, 20S-dihydroxy-12beta, 23R-epoxydammar-24-ene 3-O-{[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-20-O-[beta-D-xylopyanosyl(1-->6)]-beta-D-glucopyranoside (2) on the basis of (1)D and (2)D NMR (including (1)H, (13)C-NMR, (1)H-(1)H COSY, HSQC, TOCSY, HMBC, and NOESY), ESI-MS spectrometry and chemical methods. 相似文献
9.
One unusual triterpenoid derivative, ilekudinchoside E (1), was isolated from the leaves of Ilex kudincha. The structure was established by various spectroscopic techniques, including one‐ and two‐dimensional NMR, HRTOFMS and CD spectra. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
10.
Guan SH Xia JM Lu ZQ Chen GT Jiang BH Liu X Guo DA 《Magnetic resonance in chemistry : MRC》2008,46(2):186-190
Three new lignan glycosides (1-3) were isolated from the stems of Akebia trifoliata. Their structures were elucidated as (7R,8R,7'R,8'R)3,3',5,5'tetramethoxy-4,4'dihydroxy-7,9':7',9-diepoxylignan-4-O-beta-D-glucopyranoside (1), (7S,8S,8'R)-4,4',9-trihydroxy-3,3',5,5'-tetramethoxy-7,9'-epoxylignan-7'-one 9-O-beta-D-glucopyranoside (2), (7R,8R,8'S)-4,4',9-trihydroxy3,3',5,5'-tetramethoxy-7,9'-epoxylignan-7'-one 9-O-beta-D-glucopyranoside (3) by spectral analyses, primarily NMR, MS and CD. The NMR assignments for the compounds were carried out using 1H, 13C, DEPT, COSY, HSQC, HMBC and ROESY NMR experiments. 相似文献
11.
Two new furostanol glycosides, torvosides O (1) and P (2), were isolated from leaves of Solanum torvum. Their structures were completely and unambiguously assigned by one‐ and two‐dimensional NMR techniques (1H NMR, 13C NMR, TOCSY, HSQC, ROESY and HMBC), ESI‐MS spectrometry and chemical methods. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
12.
Two new sesquiterpene lactone xylosides, derivatives of the guaianolides 9alpha-hydroxyleucodin and 9alpha-hydroxy-11,13-dehydroleucodin, were isolated from roots of Lactuca triangulata. Their structures were established on the basis of (1)H and (13)C NMR spectra, 2D NMR (HMQC, HMBC, COSY, NOESY) techniques and comparison with the literature data. The compounds represent the first example of sesquiterpene lactone xylosides. 相似文献
13.
Two new pyrrolosesquiterpenes were isolated from cultures of the soil actinomycete Streptomyces sp. Hd7‐21. The structures of these compounds were elucidated by extensive spectroscopic analyses including MS and 1D and 2D NMR data. Their cytotoxic activity against a panel of human cancer cell lines were biologically evaluated. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
14.
Hong‐zhi Huang Wen‐bin Zhou Yang Zhao Cheng‐qi Xiong Da‐wei Tan Xin‐bo Song Bai‐ping Ma 《Magnetic resonance in chemistry : MRC》2012,50(1):79-83
Five new glucosylated steroidal glycosides, cantalasaponin I‐B1 (1), I‐B2 (2), I‐B3 (3), I‐B4 (4) and I‐B5 (5), were isolated and purified from the transformed product of the cantalasaponin I by using Toruzyme 3.0 l as biocatalyst. Their structures were elucidated on the basis of high‐resolution electrospray ionization mass spectrometry, one‐dimensional (1H and 13C NMR) and two‐dimensional [COSY, heteronuclear single‐quantum correlation (HSQC), HMBC and HSQC‐TOCSY] NMR spectral analyses and chemical evidence. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
15.
Demirkiran O Topcu G Hussain J Ahmad VU Choudhary MI 《Magnetic resonance in chemistry : MRC》2011,49(10):673-677
Two new unusual monoterpene glycosides, (Z)-3,6-dimethyl-3-(β-D-O-glucosylmethylene)cyclohept-4-ene-1-one (1) and 3,6-dimethyl-3-(β-D-O-glucosylmethylene)cycloheptanone (2) have been isolated along with five known compounds, 3-hydroxy-4-methoxybenzoic acid, 6,7-dihydroxycoumarin, luteolin, apigenin 5-O-αl-L-rhamnoside, and pinocembrin-7-O-rutinoside from ethyl acetate extract of Euphorbia decipiens. The structures of the isolated compounds were elucidated by extensive 1D- and 2D-NMR, and mass spectroscopic analyses. 相似文献
16.
dos Santos CC Sousa Lima MA Braz-Filho R de Simone CA Silveira ER 《Magnetic resonance in chemistry : MRC》2005,43(12):1012-1015
The structural characterization of two new, unusual kaurene diterpenes isolated from roots of Erythroxylum barbatum is described. 1D NMR and several 2D shift-correlated NMR pulse sequences (1H,1H-COSY, HMQC, HMBC and NOESY) were used for structure elucidation and the unambiguous 1H and 13C chemical shifts assignments. Single crystal X-ray diffraction analysis was also used to confirm the final relative configuration of the compounds possessing the C-20 methyl and the CH2-15 methylene groups in cis-orientation. 相似文献
17.
Ying Guo De‐Qiang Dou Ting‐Guo Kang Shi‐Cheng Wang Hai‐Xue Kuang 《Magnetic resonance in chemistry : MRC》2009,47(11):982-988
Two new saponins were isolated from husks of Xanthoceras sorbifolia Bunge and their structures were elucidated as 3‐O‐[β‐D‐galactopyranosyl(1→2)]‐α‐L‐arabinofuranosyl(1→3)‐β‐D‐methyl glucuronic acid‐21‐O‐(3,4‐diangeloyl)‐α‐L‐rhamnose‐3β, 16α, 21β, 22α, 28β‐pentahydroxyl‐22‐acetoxy‐olean‐12‐ene(1) and 3‐O‐[β‐D‐galactopyranosyl(1→2)]‐α‐L‐arabinofuranosyl(1→3)‐β‐D‐methyl glucuronic acid‐21,22‐O‐diangeloyl‐3β,15α,16α,21β,22α,28β‐hexahydroxyl‐olean‐12‐ene(2) on the basis of 1D and 2D NMR (including 1H, 13C‐NMR, 1H? 1H COSY, HSQC, HMBC and DEPT), ESI‐MS spectrometry and chemical methods. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
18.
Four new diterpenoids, named smaditerpenic acid A-D, together with five known compounds, were isolated from the H(2)O extract of the leaves of Smallantus sonchifolius (yacon) cultivated in Liaoning, China and their structures were elucidated on the basis of one- and two-dimensional NMR (including (1)H, (13)C-NMR, (1)H-(1)H COSY, HSQC, TOCSY, HMBC, and ROESY), electrospray ionization mass spectrometry (ESI-MS), and chemical methods. 相似文献
19.
Valentin A. Semenov Dmitry O. Samultsev Leonid B. Krivdin 《International journal of quantum chemistry》2020,120(19):e26348
The PBE0/pcSseg-2//pcseg-2 calculations of 1H and 13C NMR chemical shifts were performed for a classical series of 12 Strychnos alkaloids (except for the earlier studied parent strychnine), namely akuammicine, isostrychnine, rosibiline, tsilanine, spermostrychnine, diaboline, cyclostrychnine, henningsamide, strychnosilidine, strychnobrasiline, holstiine, and icajine. It was found that the calculated 1H and 13C NMR chemical shifts show markedly good correlations with available experimental data, as characterized by a mean absolute error of 0.22 ppm for the range of 8 ppm for protons and 1.97 ppm for the range of 180 ppm for carbons. Complementarily, the present results provide essential NMR update and fill a gap in the NMR data of this distinguished group of vitally important natural products. 相似文献
20.
Giangiacomo Beretta Giulio Vistoli Enrico Caneva Cecila Anselmi Roberto Maffei Facino 《Magnetic resonance in chemistry : MRC》2009,47(5):456-459
The complete 1H, 13C and 15N NMR spectral assignments of two new alkaloids isolated from chestnut honey and structurally related to kynurenic acid have been made using 1‐D and 2‐D NMR techniques, including COSY, HMQC and HMBC experiments. The new compounds have been identified as 3‐(2′‐pyrrolidinyl)‐kynurenic acid and its γ‐lactam derivative. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献