Structural Elucidation of a Novel Scalarane Derivative by Using High-Field (14.1T) N.M.R. Spectroscopy

1991 ◽  
Vol 44 (7) ◽  
pp. 995 ◽  
Author(s):  
PF Barron ◽  
RJ Quinn ◽  
DJ Tucker
Keyword(s):  
Long Range ◽  
Marine Sponge ◽  
High Field ◽  
Structural Elucidation ◽  
Roesy Spectrum ◽  
Complete Assignment

A novel scalarane derivative (2) has been isolated from the marine sponge Carteriospongia foliascens. A complete assignment of the 1H and 13C n.m.r. spectra of (2) was achieved by using cosy-90, 1H-detected 1H/13C correlation (HMQC sequence) and 1H-detected long-range 1H/13C correlation (HMBC sequence) experiments, all measured at 600 MHz. The assignment of stereochemistry at C4 was supported by a ROESY spectrum.

ChemInform Abstract: Isolation and Structural Elucidation of the Crellastatins I-M: Cytotoxic Bis-Steroid Derivatives from the Vanuatu Marine Sponge Crella sp.

ChemInform ◽  
2010 ◽  
Vol 31 (10) ◽  
pp. no-no
Author(s):  
Clelia Giannini ◽  
Angela Zampella ◽  
Cecile Debitus ◽  
Jean-Louis Menou ◽  
Christos Roussakis ◽  
...  
Keyword(s):  
Marine Sponge ◽  
Structural Elucidation

scholarly journals Very Long-Range Correlations (nJC,H n > 3) in HMBC Spectra

2008 ◽  
Vol 3 (3) ◽  
pp. 1934578X0800300
Author(s):  
Ramiro Araya-Maturana ◽  
Hernán Pessoa-Mahana ◽  
Boris Weiss-López
Keyword(s):  
Natural Products ◽  
Long Range ◽  
Organic Molecules ◽  
Heteronuclear Nmr ◽  
Structural Elucidation ◽  
Coupling Constants ◽  
Contour Plot ◽  
Long Range Correlations ◽  
Complex Organic

The structural elucidation of natural products and complex organic molecules relies heavily on the application of proton detected heteronuclear NMR. Among these techniques, the HMBC NMR experiment remains as the most popular among the methods that sample long range coupling constants. The HMBC (C-H) experiment allows the assignment of structural fragments through correlations between protons and carbons separated by more than one bond, usually two or three (2 JC,H and 3 JC,H). It is also possible to obtain valuable information, sometimes crucial, through very long-range, or nonstandard correlations, n JC,H n>3; they can, surprisingly, appear in standard HMBC spectra, or looked for by performing several HMBC experiments with different long-range delays and using a deeper threshold in the contour plot.

Entilins A and B, two novel heptanortriterpenoid derivatives from entandrophragma utile (meliaceae): Structural elucidation using 2d nmr long-range δC/δH correlation experiments

1990 ◽  
Vol 31 (31) ◽  
pp. 4505-4508 ◽  
Author(s):  
Jean C. Tchouankeu ◽  
Etienne Tsamo ◽  
B.Lucas Sondengam ◽  
Joseph D. Connolly ◽  
David S. Rycroft
Keyword(s):  
Long Range ◽  
2D Nmr ◽  
Structural Elucidation

On the chemistry and high field nuclear magnetic resonance spectroscopy of rapamycin

1980 ◽  
Vol 58 (6) ◽  
pp. 579-590 ◽  
Author(s):  
John A. Findlay ◽  
Lajos Radics
Keyword(s):  
High Field ◽  
Nmr Spectra ◽  
Resonance Spectroscopy ◽  
X Ray ◽  
Conformational Isomers ◽  
H Nmr ◽  
Neutral Compounds ◽  
Complete Assignment ◽  
Hydrolysis Of ◽  
C Nmr

Base catalysed hydrolysis of rapamycin (C51H79NO13) affords six neutral compounds identified by chemical and spectroscopic means as 2a, 3b, 3d, 5, 2,4-dimethylphenol, and L(−)-piperidine-2-carboxylic acid 6, and whose generation has been plausibly rationalized. These findings as well as detailed analyses of 13C nmr and 1H nmr spectra provide independent corroboration of the X-ray derived rapamycin crystal structure 1. Structurally homogeneous in the solid state, rapamycin is found to occur in solutions as a mixture of two conformational isomers (approximately 4:1). Through nearly complete assignment of the high field 1H (400 MHz) and 13C (100.6 MHz) nmr spectra, the isomerism is shown to be associated with trans–cis rotation of an amidic bond within the 31-membered macrolide ring. The predominant form corresponds to the conformer portrayed by X-ray analysis.

NMR effects of acetylation and long-range coupling as a tool for structural elucidation of hydroxychromenes

1967 ◽  
Vol 8 (43) ◽  
pp. 4201-4206 ◽  
Author(s):  
A. Arnone ◽  
G. Cardillo ◽  
L. Merlini ◽  
R. Mondelli
Keyword(s):  
Long Range ◽  
Structural Elucidation

Polyketides from a marine sponge-derived fungusMycelia steriliaand proton-proton long-range coupling

2008 ◽  
Vol 46 (12) ◽  
pp. 1148-1152 ◽  
Author(s):  
Gao Hao ◽  
Zhang Qing-Hua ◽  
Jiang Miao-Miao ◽  
Tang Jin-Shan ◽  
Miao Cheng-Du ◽  
...  
Keyword(s):  
Long Range ◽  
Marine Sponge ◽  
Proton Proton

Application of High-Field NMR and Cryogenic Probe Technologies in the Structural Elucidation of Poecillastrin A, a New Antitumor Macrolide Lactam from the SpongePoecillastraSpecies

2002 ◽  
Vol 4 (19) ◽  
pp. 3293-3296 ◽  
Author(s):  
Mohammad A. Rashid ◽  
Kirk R. Gustafson ◽  
Ronald C. Crouch ◽  
Amiram Groweiss ◽  
Lewis K. Pannell ◽  
...  
Keyword(s):  
High Field ◽  
Structural Elucidation ◽  
Cryogenic Probe
Sign in / Sign up

Export Citation Format

Share Document