scholarly journals Automatic Structure Elucidation through Data Base Search and 2D NMR Spectral Analysis

2006 ◽  
Vol 1 (1) ◽  
pp. 1934578X0600100 ◽  
Author(s):  
Jean-Marc Nuzillard ◽  
Vicente de Paulo Emerenciano
Keyword(s):  
Data Base ◽  
Structure Elucidation ◽  
Chemical Shifts ◽  
2D Nmr ◽  
Extraction Process ◽  
Structural Constraints ◽  
Nmr Data ◽  
Automatic Structure ◽  
Structure Generator ◽  
C Nmr

This work shows how two expert systems, LSD and SISTEMAT, can be used together to solve structure elucidation problems that were selected from recent literature articles. The LSD system is a structure generator that mainly relies on homo- and heteronuclear 2D NMR data. It lacks the knowledge of chemical shift values and of natural product chemistry. Conversely, the SISTEMAT data base contains about 20000 natural compounds and refers to both their 13C NMR chemical shifts and their botanical origin. When exploited by dedicated computer programs it yields structural constraints such as skeletal types and ring systems. The botanical and spectroscopic data in SISTEMAT proved to be very complementary in the constraints extraction process. Several application examples of the proposed methodology are described in detail.

NMR-spektroskopische Untersuchungen an 1,1-Thiophendioxid und verwandten Verbindungen / NMR Spectroscopical Investigations of Thiophene 1,1-Dioxide and Related Compounds

1984 ◽  
Vol 39 (7) ◽  
pp. 915-920 ◽  
Author(s):  
Herbert Meier ◽  
Thomas Molz ◽  
Heinz Kolshorn
Keyword(s):  
Computer Simulation ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Multiple Resonance ◽  
Nmr Data ◽  
Cyclic Diene ◽  
Related Compounds ◽  
C Nmr

The 1H and 13C NMR data of thiophene 1,1-dioxide (3) and related compounds, especially of the precursor 2 and the consecutive product 5 are evaluated by computer simulation and multiple resonance. Chemical shifts and coupling constants reveal that 3 has the character of a cyclic diene. Diatropic or paratropic effects can be excluded.

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 DP4-Assisted Structure Elucidation of Isodemethylchodatin, a New Norlichexanthone Derivative Meager in H-Atoms, from the Lichen Parmotrema tsavoense

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1527 ◽  
Author(s):  
Thuc-Huy Duong ◽  
Mehdi A. Beniddir ◽  
Joël Boustie ◽  
Kim-Phi-Phung Nguyen ◽  
Warinthorn Chavasiri ◽  
...  
Keyword(s):  
Computational Chemistry ◽  
13C Nmr ◽  
Structure Elucidation ◽  
Methoxy Group ◽  
Chemical Shifts ◽  
13C Nmr Chemical Shifts ◽  
Nmr Data ◽  
Phytochemical Investigation ◽  
Integrated Interpretation ◽  
Foliose Lichen

A phytochemical investigation of the foliose lichen Parmotrema tsavoense (Krog and Swinscow) Krog and Swinscow (Parmeliaceae) resulted in the isolation of a new trichlorinated xanthone, isodemethylchodatin. The structure elucidation of this new norlichexanthone derivative proved tricky owing to proton deficiency, and to the lack of NMR data of closely related analogues. The structure of this compound was determined based on an integrated interpretation of 13C-NMR chemical shifts, MS spectra, and DP4-based computational chemistry was also performed to provide an independent and unambiguous validation of the determined structure. Isodemethylchodatin represents the first chlorinated lichexanthone/norlichexanthone derivative bearing a methoxy group at C-5.

scholarly journals Two New Ballonigrin-type Diterpenoids from the Roots of Ballota limbata

2012 ◽  
Vol 7 (2) ◽  
pp. 1934578X1200700
Author(s):  
Umar Farooq ◽  
Afsar Khan ◽  
Ather Farooq Khan ◽  
Saleha Suleman Khan ◽  
Rizwana Sarwar ◽  
...  
Keyword(s):  
Structure Elucidation ◽  
2D Nmr ◽  
C Nmr

Two new ballonigrin type lactone diterpenoids, named ballonigrin lactone A and B, have been isolated from the roots of Ballota limbata. Structure elucidation of the isolated compounds was based on spectroscopic {IR, 1H- and 13C-NMR, and 2D-NMR (HMQC, HMBC, COSY and NOESY} and EI-MS data.

Juglomycins G-J: Isolation from Streptomycetes and Structure Elucidation

2005 ◽  
Vol 60 (2) ◽  
pp. 183-188 ◽  
Author(s):  
R. P. Maskey ◽  
H. Lessmann ◽  
S. Fotso ◽  
I. Grün-Wollny ◽  
H. Lackner ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Absolute Configuration ◽  
Structure Elucidation ◽  
Mass Spectra ◽  
2D Nmr ◽  
Cd Spectra ◽  
Streptomyces Spp ◽  
Nmr Data ◽  
Related Compounds ◽  
Weak Antibacterial Activity

From the Streptomyces spp. 815 and GW4184, four new 4-juglon-2-ylbutyric acid derivatives, the juglomycins G - J (3a, 4a, 4c, 5c), have been isolated and characterised. The structures were derived from the 1D and 2D NMR data and mass spectra and confirmed by comparison with structurally related compounds. The absolute configuration was deduced from the CD spectra. The new natural products exhibited weak antibacterial activity similar to juglomycin A (5a).

Dammarane and Ceanothane Triterpenes from Zizyphus glabrata

2006 ◽  
Vol 61 (1) ◽  
pp. 87-92 ◽  
Author(s):  
Seru Ganapaty ◽  
Pannakal S. Thomas ◽  
Kancharalapalli V. Ramana ◽  
Gloria Karagianis ◽  
Peter G. Waterman
Keyword(s):  
Bactericidal Activity ◽  
Chemical Constituents ◽  
2D Nmr ◽  
First Report ◽  
Nmr Data ◽  
C Nmr ◽  
Dammarane Glycoside

From the leaves of Zizyphus glabrata, a new dammarane-type triterpene, pseudojujubogenin -3-O- β -D-glucopyranoside, along with the known ceanothane triterpenes, granulosic acid, ceanothic acid and daucosterol were isolated. The structures of the compounds were fully characterized by detailed NMR investigations including 1H and 13C NMR, HSQC, COSY, HMBC and NOESY experiments. In addition, the dammarane glycoside was tested for its potential to inhibit various bacteria and was found to possess significant bactericidal activity. The 1H, 13C and full 2D-NMR data on granulosic acid has also been presented. This is the first report on the chemical constituents of the leaves of Z. glabrata.

Computer-assisted structure elucidation of natural products with limited 2D NMR data: application of the StrucEluc system

2003 ◽  
Vol 41 (5) ◽  
pp. 359-372 ◽  
Author(s):  
Kirill A. Blinov ◽  
Dean Carlson ◽  
Mikhail E. Elyashberg ◽  
Gary E. Martin ◽  
Eduard R. Martirosian ◽  
...  
Keyword(s):  
Natural Products ◽  
Structure Elucidation ◽  
2D Nmr ◽  
Computer Assisted ◽  
Nmr Data ◽  
Data Application ◽  
Computer Assisted Structure Elucidation

Alteration of O-specific polysaccharide structure of symbiotically defective Mesorhizobium loti mutant 2213.1 derived from strain NZP2213.

2008 ◽  
Vol 55 (1) ◽  
pp. 191-200 ◽  
Author(s):  
Anna Turska-Szewczuk ◽  
Hubert Pietras ◽  
Wojciech Borucki ◽  
Ryszard Russa
Keyword(s):  
Wild Type Strain ◽  
2D Nmr ◽  
Chain Structure ◽  
Wild Type ◽  
Immunoblot Assay ◽  
Mesorhizobium Loti ◽  
Nmr Data ◽  
Specific Polysaccharide ◽  
C Nmr

Mesorhizobium loti mutant 2213.1 derived from the wild-type strain NZP2213 by Tn5 mutagenesis showed impaired effectiveness of symbiosis with the host plant Lotus corniculatus (Turska-Szewczuk et al., 2007 Microbiol Res, in press). The inability of lipopolysaccharide (LPS) isolated from the mutant 2213.1 strain or de-O-acetylated LPS of the parental cells to inactivate phage A1 particles implicated alterations in the LPS structure. The O-specific polysaccharide of the mutant was studied by chemical analyses along with (1)H and (13)C NMR spectroscopy, which clearly confirmed alterations in the O-chain structure. 2D NMR data showed that the mutant O-polysaccharide consists of a tetrasaccharide repeating unit containing non-substituted as well as O-acetylated or O-methylated 6-deoxytalopyranose residues. Additionally, an immunogold assay revealed a reduced number of gold particles on the mutant bacteroid cell surface, which could result from both a diminished amount of an O-antigenic determinant in mutant LPS and modifications of structural epitopes caused by alterations in O-acetylation or O-methylation of sugar residues. Western immunoblot assay of alkaline de-O-acetylated lipophilic M. loti NZP2213 LPS showed no reactivity with homologous serum indicating a role of O-acetyl groups in its O-specificity.

scholarly journals Structure Revision and Protein Tyrosine Phosphatase Inhibitory Activity of Drazepinone

Marine Drugs ◽  
2021 ◽  
Vol 19 (12) ◽  
pp. 714
Author(s):  
Fei Cao ◽  
Li Pan ◽  
Wen-Bin Gao ◽  
Yun-Feng Liu ◽  
Cai-Juan Zheng ◽  
...  
Keyword(s):  
Detailed Analysis ◽  
Protein Tyrosine Phosphatase ◽  
Inhibitory Activity ◽  
Chemical Shifts ◽  
Tyrosine Phosphatase ◽  
2D Nmr ◽  
Nmr Data ◽  
Structure Revision ◽  
Ic50 Values

From the marine-derived fungus Penicillium sumatrense (Trichocomaceae), a pair of enantiomers [(+)-1 and (−)-1] were isolated with identical 1D NMR data to drazepinone, which was originally reported to have a trisubstituted naphthofuroazepinone skeleton. In this study, we confirmed the structures of the two enantiomers as drazepinone and revised their structures by detailed analysis of extensive 2D NMR data and a comparison of the calculated 13C chemical shifts, ECD, VCD, and ORD spectra with those of the experiment ones. (+)-1 and (−)-1 were evaluated for their PTP inhibitory activity in vitro. (−)-1 showed selective PTP inhibitory activity against PTP1B and TCPTP with IC50 values of 1.56 and 12.5 μg/mL, respectively.

Sign in / Sign up

Export Citation Format

Share Document