1 H and 13 C NMR assignments of sesquiterpenes from Dysidea fragilis

2015 ◽  
Vol 53 (12) ◽  
pp. 1057-1060 ◽  
Author(s):  
Nguyen Xuan Nhiem ◽  
Nguyen Thi Cuc ◽  
Dan Thi Thuy Hang ◽  
Do Thi Trang ◽  
Nguyen Hoai Nam ◽  
...  
Keyword(s):  
Nmr Assignments ◽  
C Nmr

scholarly journals Flavonoids from Curcuma longa Leaves and their NMR Assignments

2015 ◽  
Vol 10 (1) ◽  
pp. 1934578X1501000 ◽  
Author(s):  
Chia-Ling Jiang ◽  
Sheng-Fa Tsai ◽  
Shoei-Sheng Lee
Keyword(s):  
Nmr Assignments ◽  
Soluble Fraction ◽  
Curcuma Longa ◽  
2D Nmr ◽  
Etoh Extract ◽  
Spectroscopic Analyses ◽  
Nmr Data ◽  
The Common ◽  
Reported Data ◽  
C Nmr

Chemical investigation of the n-BuOH-soluble fraction of the EtOH extract of the aerial part of Curcuma longa led to the isolation of 11 flavonol glycosides and one dihydroflavonol glucoside (1) via chromatography over Sephadex LH-20 and Lobar RP-18 columns. Although they are known, the 1H and 13C NMR data recorded in CD3OD rather than the common DMSO- d6 are doubly checked via extensive 2D NMR spectroscopic analyses, leading to some revisions of the reported data, especially for the glycon part.

scholarly journals Structural Elucidation of Pimarane and Isopimarane Diterpenoids: The 13C NMR Contribution

2008 ◽  
Vol 3 (3) ◽  
pp. 1934578X0800300 ◽  
Author(s):  
Ana M. L. Seca ◽  
Diana C. G. A. Pinto ◽  
Artur M. S. Silva
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Nmr Assignments ◽  
Structural Elucidation ◽  
Synthetic Compounds ◽  
Chiral Centers ◽  
Pimarane Diterpenoids ◽  
Biosynthetic Studies ◽  
C Nmr ◽  
Natural And Synthetic

13C NMR spectroscopy is actually one of the first tools used for the structural elucidation of natural and synthetic compounds and it is also used in biosynthetic studies. The aim of this review is to present the 13C NMR assignments of a large number of pimarane diterpenoids, describing the most significant effects caused by different substitution patterns and different stereochemistry at their chiral centers.

scholarly journals 1 H and 13 C NMR assignments for (N -Methyl)-(−)-(α)-isosparteinium iodide and (N -Methyl)-(−)-sparteinium iodide

2018 ◽  
Vol 57 (1) ◽  
pp. 55-64 ◽  
Author(s):  
Kavoos Kolahdouzan ◽  
O. Maduka Ogba ◽  
Daniel J. O'Leary
Keyword(s):  
Nmr Assignments ◽  
C Nmr

1 H and 13 C NMR assignments of new ecdysteroids from Callisia fragrans

2015 ◽  
Vol 53 (5) ◽  
pp. 379-382 ◽  
Author(s):  
Dan Thi Thuy Hang ◽  
Nguyen Thi Minh Hang ◽  
Hoang Le Tuan Anh ◽  
Nguyen Xuan Nhiem ◽  
Cao Thi Hue ◽  
...  
Keyword(s):  
Nmr Assignments ◽  
C Nmr

Synthesis and characterization of a series of 4-methyl-1-[2-aryl-1-diazenyl]-1,4-diazepanes and 1,4-di-[2-aryl-1-diazenyl]-1,4-diazepanes

2004 ◽  
Vol 82 (12) ◽  
pp. 1725-1735 ◽  
Author(s):  
Shasta Lee Moser ◽  
Keith Vaughan
Keyword(s):  
Nmr Assignments ◽  
Diazonium Salt ◽  
Variable Temperature ◽  
2D Nmr ◽  
Diazonium Salts ◽  
X Ray Diffraction ◽  
X Ray ◽  
New Compounds ◽  
C Nmr

1-Methylhomopiperazine was coupled with a series of diazonium salts to afford the 4-methyl-1-[2-aryl-1-diazenyl]-1,4-diazepanes (6), a new series of triazenes. These compounds are, in the main, stable crystalline solids (some of the series are stable oils), and they have been characterized by 1H and 13C NMR spectroscopy, IR spectroscopy, and mass spectrometry. NMR assignments were determined by 2D NMR and variable-temperature NMR experiments and by comparison with model compounds. A second series of new compounds, namely, 1,4-di-[2-aryl-1-diazenyl]-1,4-diazepanes (5), were prepared by coupling unsubstituted homopiperazine (1,4-diazepane) with 2 molar equivalents of the diazonium salt and were similarly characterized. The crystal and molecular structure of the parent member of this bis-triazene series (5, X = H) has been determined by single-crystal X-ray diffraction analysis.Key words: triazene, bis-triazene, diazenyl, bis-diazenyl, diazonium salt, NMR, diazepane.

1 H and 13 C NMR assignments for two new cordiaquinones from roots of Cordia leucocephala

2008 ◽  
Vol 47 (2) ◽  
pp. 190-193 ◽  
Author(s):  
Jaécio Carlos Diniz ◽  
Francisco Arnaldo Viana ◽  
Odaci Fernandes Oliveira ◽  
Maria Aparecida M. Maciel ◽  
Maria da Conceição de Menezes Torres ◽  
...  
Keyword(s):  
Nmr Assignments ◽  
C Nmr

Calculated and Experimental 1 H and 13 C NMR Assignments for Cannabicitran

2021 ◽  
Author(s):  
Jared S. Wood ◽  
William H. Gordon ◽  
Jeremy B. Morgan ◽  
R. Thomas Williamson
Keyword(s):  
Nmr Assignments ◽  
C Nmr

Stereoselective synthesis and stereochemistry of r-2-alkoxycarbonyl-c-3-o-substituted phenyl-1,4-thiazane 1,1-dioxides

2005 ◽  
Vol 83 (3) ◽  
pp. 202-208
Author(s):  
N Bhavani ◽  
S Perumal ◽  
R Banureka
Keyword(s):  
Long Range ◽  
Trans Isomer ◽  
Stereoselective Synthesis ◽  
Nmr Assignments ◽  
Chair Conformation ◽  
Coupling Constant ◽  
Vicinal Coupling Constant ◽  
Relative Configuration ◽  
Cis Isomer ◽  
C Nmr

r-2-Alkoxycarbonyl-c-3-aryl-1,4-thiazane 1,1-dioxides were obtained as the stereoselective product, when the aldehyde used was o-substituted benzaldehyde while the p-substituted benzaldehydes gave a trans product. The relative configuration of the adjacent alkoxycarbonyl and aryl groups was assigned from the vicinal coupling constant, 3J = 10.6 Hz in the trans isomer and 3.2 Hz in the cis isomer, and from the multiplicity pattern, i.e., a doublet for the H-2 proton of the trans isomer and a triplet for the H-2 proton of the cis isomer. The unusual, large long-range coupling (4J = 2.8 Hz) because of the "W" arrangement between H-2e and H-6e across the ring type was very useful for confirming the cis configuration and chair conformation of the isomer. The various 1H and 13C NMR assignments were made with the help of 1H–1H COSY, 1H–13C COSY, HMBC, and NOESY spectral analyses.Key words: 1H and 13C NMR, 1H–1H COSY, 1H–13C COSY, HMBC, NOESY, stereoselectivity, 1,4-thiazane.

Notizen: Synthese und NMR-spektroskopische Eigenschaften von Benzyl-2,3-anhydro-4-desoxy-4-[N]-pyridinium-pyranosiden/Synthesis and NMR Spectroscopic Properties of Several Benzyl 2,3-Anhydro-4-deoxy-4-[N]-pyridinium Pyranosides

1992 ◽  
Vol 47 (4) ◽  
pp. 589-590 ◽  
Author(s):  
Wolfgang Kowollik ◽  
Wolfgang Voelter
Keyword(s):  
Room Temperature ◽  
Nmr Assignments ◽  
Spectroscopic Properties ◽  
Single Frequency ◽  
Group Effect ◽  
C Nmr

Benzyl 2,3-anhydro-4-0-triflyl-β-L-ribopyranoside (1) and benzyl 2,3-anhydro-4-O-triflyl-α-D-lyxopyranoside (3) react with pyridine to give benzyl 2,3-anhydro-4-deoxy-4-[N]-pyridinium - α-D-lyxopyranoside triflate (2) and benzyl 2,3-anhydro-4-deoxy-4-[N]-pyridinium -β-L-ribopyranoside triflate (4). Similar reactions with thiourea and dimethylsulfoxide are mentioned. Compound 2 is stable at room temperature, whereas compound 4 decomposes in a few hours (neighbouring group effect). The 13C NMR assignments of 2 are proved by 13C {1H} single frequency decoupling experiments.

scholarly journals Bromotyrosine Alkaloids with Acetylcholinesterase Inhibitory Activity from the Thai Sponge Acanthodendrilla sp

2015 ◽  
Vol 10 (11) ◽  
pp. 1934578X1501001 ◽  
Author(s):  
Natchanun Sirimangkalakitti ◽  
Opeyemi J. Olatunji ◽  
Kanokwan Changwichit ◽  
Tongchai Saesong ◽  
Supakarn Chamni ◽  
...  
Keyword(s):  
Inhibitory Activity ◽  
Nmr Assignments ◽  
Therapeutic Potential ◽  
2D Nmr ◽  
Inhibition Kinetics ◽  
Ache Inhibitory Activity ◽  
First Time ◽  
Kinetics Of ◽  
Resolution Mass ◽  
C Nmr

Twenty bromotyrosine alkaloids, including a new compound, 13-oxosubereamolline D (5), were isolated from the Thai sponge Acanthodendrilla sp. Their structures were determined by analyses of 1D- and 2D-NMR, high-resolution mass, and circular dichroism data. The complete 1H and 13C NMR assignments of 5,7β-dichlorocavernicolin (19) and 5,7α-dichlorocavernicolin (20) are described herein for the first time. The acetylcholinesterase (AChE) inhibitory activity of all isolated compounds was evaluated. Only homoaerothionin (7) and fistularin 1 (10) exhibited inhibitory activity against human recombinant AChE ( hrAChE) with IC50s of 4.5 and 47.5 μM, respectively. The hrAChE inhibition kinetics of 7, the most potent alkaloid, showed increased K m and unchanged V max values, suggesting its competitive mode of inhibition. The spirocyclohexadienylisoxazole and the length of the alkyl diamine linkage were proposed as the crucial parts for its strong inhibitory activity. This finding indicates a therapeutic potential for 7 in acetylcholine-related diseases, most importantly Alzheimer's disease.

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