共查询到20条相似文献,搜索用时 31 毫秒
1.
《Magnetic resonance in chemistry : MRC》2002,40(11):752-754
An NMR study of five highly functionalized and rearranged abietane diterpenoids is described. In addition to 1D NMR methods, including 1D NOESY spectra, 2D shift‐correlated experiments [1H, 13C‐gHSQC‐1J (C,H) and 1H, 13C‐gHMBC‐nJ (C,H) (n = 2 and 3)] were used for the complete and unambiguous 1H and 13C chemical shift assignments of these substances. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
2.
《Magnetic resonance in chemistry : MRC》2002,40(9):618-621
The assignments of 1H and 13C NMR spectra for three new triterpene saponins from Silene vulgaris (gypsogenin 3‐O‐glucuronide, quillaic acid 3‐O‐glucuronide, and gypsogenin 3‐O‐glycoside) are reported. In addition to 1D NMR methods, 2D NMR techniques (COSY, HSQC, HMBC, and HSQC‐TOCSY) were used for the assignments. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
3.
Aline Lima de Oliveira Carlos Henrique Alves de Oliveira Laura Maia Mairink Francine Pazini Ricardo Menegatti Luciano Morais Lião 《Magnetic resonance in chemistry : MRC》2011,49(8):537-542
Complete assignment of 1H and 13C NMR chemical shifts and J(1H/1H and 1H/19F) coupling constants for 22 1‐phenyl‐1H‐pyrazoles' derivates were performed using the concerted application of 1H 1D and 1H, 13C 2D gs‐HSQC and gs‐HMBC experiments. All 1‐phenyl‐1H‐pyrazoles' derivatives were synthesized as described by Finar and co‐workers. The formylated 1‐phenyl‐1H‐pyrazoles' derivatives were performed under Duff's conditions. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
4.
《Magnetic resonance in chemistry : MRC》2003,41(3):206-212
Unambiguous and complete assignments of 1H and 13C NMR chemical shifts for 15 limonoids, eight of them found in natural sources and seven other synthetic derivatives, are presented. The assignments are based on 2D shift‐correlated [1H,1H‐COSY, 1H,13C‐gHSQC‐1J(C,H), 1H,13C‐gHMBC‐nJ(C,H) (n = 2 and 3)] and NOE experiments. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
5.
Jinhe Jiang Ying Liu Kang Min Bi Jing Liqin Wang Yan Zhang Yegao Chen 《Helvetica chimica acta》2010,93(6):1187-1191
Two new lycopodine alkaloids, (12β)‐12‐hydroxyhuperzine G ( 1 ) and (5β,6β,15α)‐15‐methyllycopodane‐5,6‐diol ( 2 ), were isolated from the whole plants of Huperzia serrata, together with six known compounds, huperzines A, B, and G, phlegmariurine B, (8β)‐8‐hydroxyphlegmariurine B, and lycoposerramine D. Their structures were elucidated on the basis of spectroscopic analysis, including HR‐ESI‐MS, 1H‐ and 13C‐NMR, DEPT, 1H,1H‐COSY, HSQC, HMBC, and NOESY data. 相似文献
6.
Aslan Esmurziev Nebojša Simić Eirik Sundby Bård Helge Hoff 《Magnetic resonance in chemistry : MRC》2009,47(5):449-452
Complete assignments of 1H‐ and 13C‐NMR resonances of five methyl tetra‐O‐benzoyl‐D‐pyranosides based on 1H, 13C, 2D DQF–COSY, HMQC, HMBC and HSQC–TOCSY experiments have been performed. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
7.
Roqueline Rodrigues Silva de Miranda Grácia Divina de Fátima Silva Lucienir Pains Duarte Sidney Augusto Vieira Filho 《Helvetica chimica acta》2007,90(4):652-658
The triterpene ester (3β)‐olean‐18‐en‐3‐yl stearate ( 1 ), together with (3β)‐urs‐12‐en‐3‐yl stearate ( 2 ), and (3β)‐lup‐20(29)‐en‐3‐yl stearate ( 3 ) were isolated from leaves of Maytenus salicifolia Reissek (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). 相似文献
8.
Valerie Huemer Gernot A. Eller Wolfgang Holzer 《Magnetic resonance in chemistry : MRC》2010,48(6):476-482
Various [5,6]pyrano[2,3‐c]pyrazol‐4(1H)‐thiones were synthesized in high yields by treatment of the corresponding [5,6]pyrano[2,3‐c]pyrazol‐4(1H)‐ones with Lawesson's reagent. Detailed NMR spectroscopic studies were undertaken of the title compounds. Complete and unambiguous assignment of chemical shifts (1H, 13C, 15N) and coupling constants (1H,1H; 13C,1H) was achieved by the combined application of various one‐ and two‐dimensional (1D and 2D) NMR spectroscopic techniques. Unequivocal mapping of most 13C,1H spin coupling constants is accomplished by 2D (δ, J) long‐range INEPT spectra with selective excitation. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
9.
Study of spontaneous E/Z isomerization of bis[(Z)‐cyanomethylidene]‐diazapentacyclodienedicarboxylates by 1H, 13C,and 15N NMR spectroscopy,X‐ray,and quantum chemical calculation data
下载免费PDF全文
![点击此处可从《Magnetic resonance in chemistry : MRC》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Andrei V. Afonin Alexander V. Vashchenko Alexander I. Albanov Valentina V. Nosyreva Anastasiya G. Mal'kina Boris A. Trofimov 《Magnetic resonance in chemistry : MRC》2017,55(6):563-569
X‐ray data show that the diethyl 6,13‐bis[(Z)‐cyanomethylidene]‐5,5,14,14‐tetramethyl‐4,15‐dioxa‐7,12‐diazapentacyclo[9.5.2.02,10.03,7.012,16]octadeca‐8,17‐diene‐10,17‐dicarboxylate is formed as the ZZ isomer and diastereomer with the (1R*,2R*,3R*,10S*,11R*,12R*,16R*) configuration. The 1H, 13C, and 15N NMR data exhibit that on standing in chloroform‐d solution, there is a spontaneous isomerization of this compound resulting in a thermodynamically stable mixture of the ZZ, ZE, EE, and EZ isomers with the same backbone. Using the 2D [1H–1H] COSY, [1H–13C] HSQC, and [1H–13C, 1H–15N] HMBC NMR techniques and quantum chemical calculations makes it possible a complete assignment of signals in the 1H, 13C, and 15N NMR spectra of each of the isomers. Such isomerization does not occur for similar compounds with the more bulky substituents at the 1,3‐oxazolidine rings. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
10.
A new megastigmane palmitate, 9‐oxomegastigm‐5(13)‐ene‐2β‐palmitate ( 1 ), and a new oleanane triterpenoid, (3β)‐3,23,28‐trihydroxyolean‐12‐en‐11‐one ( 2 ), together with three known oleanane‐type triterpenoids, β‐amyrin ( 3 ), erythrodiol ( 4 ), and (3β)‐olean‐12‐ene‐3,23,28‐triol ( 5 ), were isolated from the aerial parts of Aster yomena (Asteraceae). Their structures were identified based on 1D‐ and 2D‐NMR analysis, including 1H,1H‐COSY, HSQC, HMBC, and NOESY techniques. 相似文献
11.
《Magnetic resonance in chemistry : MRC》2002,40(8):551-553
Phytochemical investigation of the dichloromethane extract from the leaves of Daphne gnidium L. afforded 2‐(4‐hydroxy‐3,5‐dimethoxyphenyl)‐3‐hydroxymethyl‐2,3‐dihydro‐1,4,5‐trioxaphenanthren‐6‐one, and its structure was determined by a combination of spectral methods (1D and 2D 1H, 13C NMR and HRMALDI and EI mass spectrometry). The new compound was found to possess moderate antibacterial activity against Staphylococcus aureus and Bacillus cereus. However, it showed no cytotoxic activity against KB cells. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
12.
《Magnetic resonance in chemistry : MRC》2002,40(8):541-544
Two novel oligosaccharides, mono‐ and difructosyllactosucrose {[O‐β‐D ‐fructofuranosyl‐(2 → 1)]n‐β‐D ‐fructofuranosyl‐O‐[β‐D ‐galactopyranosyl‐(1 → 4)]‐α‐D ‐glucopyranoside, n = 1 and 2} were synthesized using 1F‐fructosyltransferase purified form roots of asparagus (Asparagus officinalis L.). Their 1H and 13C NMR spectra were assigned using several NMR techniques. The spectral analysis was started from two anomeric methines of aldose units, galactose and glucose, since they showed separate characteristic signals in their 1H and 13C NMR spectra. After assignments of all the 1H and 13C signals of two units of aldose, they were discriminated as galactose and glucose using proton–proton coupling constants. The HMBC spectrum revealed the galactose residue attached to C‐4 of glucose, fructose residue attached to the C‐1 of glucose, and further fructosyl fructose linkage extended from the glucosyl fructose residues. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
13.
《Journal of heterocyclic chemistry》2017,54(1):570-574
Reactions of indole‐2,3‐diones with biuret afforded 1,3‐dihydro‐3‐ureidoformimido‐2H‐indol‐2‐ones and spiro[3H‐indole‐3,2′(1′H )‐(1,3,5)triazine]‐2,4′,6′(1H ,3′H ,5′H )‐triones indicated these to be solvent dependent. The chemical structures of the products were elucidated by their comprehensive spectroscopic (IR, 1H‐NMR, 13C‐NMR, 19F‐NMR, and Mass) as well as analytical analysis. 相似文献
14.
《Magnetic resonance in chemistry : MRC》2003,41(9):718-720
A novel dihydroisocoumarin, 3,4‐dihydro‐6,8‐dihydroxy‐3‐(2′‐acetyl‐3′‐hydroxy‐5′‐methoxy)methyl‐1H‐[2]benzopyran‐1‐one, was isolated from the chloroform extract of the sap of the traditional herb Aloe vera. Its structure was determined by high‐resolution negative fast atom bombardment mass spectrometry (MS), 2D NMR spectroscopy and x‐ray crystallography. The molecular structure was elucidated by 2D NMR analysis. The complete assignment of the 1H and 13C NMR spectra of this compound was performed by using 1H detected one‐bond heteronuclear multiple quantum correlation (HMQC) and long‐range (two and three bonds) heteronuclear multiple quantum bond correlation (HMBC) experiments. Detailed analyses of the one‐ and two‐dimensional NMR techniques are presented in additional to the spectral properties (MS, IR and UV). Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
15.
《Magnetic resonance in chemistry : MRC》2003,41(8):629-632
3α‐Acetyl‐20(29)‐lupene‐24‐oic acid ( 1 ) was isolated from the gum resin of Boswellia serrata. Its presence evidently suggests, that the oxidosqualene triterpene pathway of Boswellia serrata closely resembles the biosynthetic route already found in other plants. Complete 1H and 13C spectral assignments were derived from 1D and 2D NMR spectra. This is the first compound with the lupene backbone combining a 3α‐hydroxy or 3α‐acetyl group with the 24‐carboxyl group, a configuration which is typical of the classical boswellic acids. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
16.
Anew and 20 known compounds were isolated from Bidens pilosa L. var. minor (Blume) Sherff. The new compound was determined as 7‐phenyl‐hepta‐4,6‐diyne‐2‐ol by various physical techniques (MS, IR, UV, 1H‐, 13C‐NMR, and 2D‐NMR). 相似文献
17.
18.
Dionisia Sanz Almudena Perona RosaM. Claramunt Elena Pinilla M.Rosario Torres Jos Elguero 《Helvetica chimica acta》2006,89(7):1290-1303
The new N‐salicylideneheteroarenamines 1 – 4 were prepared by reacting the biologically relevant 3‐hydroxy‐4‐pyridinecarboxaldehyde ( 5 ) with 1H‐imidazol‐1‐amine ( 6 ), 1H‐pyrazol‐1‐amine ( 7 ), 1H‐1,2,4‐triazol‐1‐amine ( 8 ), and 1H‐1,3,4‐triazol‐1‐amine ( 9 ). Solution 1H‐, 13C‐, and 15N‐NMR were used to establish that the hydroxyimino form A is the predominant tautomer. A combination of 13C‐ and 15N‐CPMAS‐NMR with X‐ray crystallographic studies confirms that the same form is present in the solid state. The stabilities and H‐bond geometries of the different forms, tautomers and rotamers, are discussed by using B3LYP/6‐31G** calculations. 相似文献
19.
《Magnetic resonance in chemistry : MRC》2003,41(4):260-264
Complete 1H and 13C resonance assignments were carried out for a new type of carboxyl‐linked glucosides of chenodeoxycholic (3α,7α‐dihydroxy‐5β‐cholan‐24‐oic) and hyodeoxycholic (3α,6α‐dihydroxy‐5β‐cholan‐24‐oic) acids by using several homonuclear (1H–1H) and heteronuclear (1H–13C) 2D NMR techniques. Differences in the 1H and 13C resonances between the α‐ and β‐anomers of the ester glucosides of bile acids were clarified for the first time. A comparison of the 1H and 13C signal shifts induced by β‐D ‐glucosidation at the 24‐carboxyl and 3α‐hydroxyl groups in the parent 5β‐cholanoic acid was also made. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
20.
A novel 30‐nortriterpenoid saponin, (3β)‐3‐hydroxy‐30‐noroleana‐12,20(29)‐dien‐28‐oic acid 3‐(β‐D ‐glucopyranosiduronic acid 6‐methyl ester) ( 1 ), and a known compound, (3β)‐oleanolic acid 3‐(β‐D ‐glucopyranosiduronic acid 6‐methyl ester) ( 2 ), were isolated from the aerial parts of Wedelia chinensis. The structures were established by their spectral data including 1H‐ and 13C‐NMR, 1H,1H‐COSY, HMBC, HSQC, NOESY, and HR‐FAB‐MS data. 相似文献