Revised structure of a delta-aminolevulinic acid derivative

1993 ◽  
Vol 39 (9) ◽  
pp. 1867-1871 ◽  
Author(s):  
M Kajiwara ◽  
K Hara ◽  
K Takatori ◽  
K Matsumoto
Keyword(s):  
Aminolevulinic Acid ◽  
Nuclear Overhauser Effect ◽  
Correlation Spectroscopy ◽  
Molecular Formula ◽  
X Ray ◽  
Overhauser Effect ◽  
13C Nuclear Magnetic Resonance ◽  
Relative Arrangement ◽  
Effect Difference ◽  
Nuclear Overhauser

Abstract The structure of the fluorescent derivative formed in the method of Okayama et al. (Clin Chem 1990; 36:1494-7) for determining delta-aminolevulinic acid (ALA) concentrations was reinvestigated after esterification. The molecular ion peak at m/z 303.1473 corresponded to the molecular formula of C17H21NO4 (calcd 303.1470). The infrared spectrum showed the presence of carbonyl and carboxyl groups. This compound contained two acetyl groups, two methyl groups, and one methoxycarbonylethyl group, as revealed by 1H and 13C nuclear magnetic resonance and 13C-1H shift-correlated spectroscopy. Experiments with correlation spectroscopy via long-range coupling indicated that the main skeleton is 3H-pyrrolizine. The relative arrangement of functional groups was determined by means of nuclear Overhauser effect difference experiments. We were led to the conclusion that the methyl ester of the derivative is 2,6-diacetyl-1,5-dimethyl-7-(2-methoxycarbonylethyl)-3H-pyrrolizine. This structure was unequivocally confirmed by x-ray analysis; therefore, the structure of the derivative itself is 2,6-diacetyl-1,5-dimethyl-7-(2-carboxyethyl)-3H-pyrrolizine.

The isolation, structure, and stereochemistry of traversiadiene. The precursor hydrocarbon of traversianal biosynthesis

1989 ◽  
Vol 67 (8) ◽  
pp. 1302-1304 ◽  
Author(s):  
Albert Stoessl ◽  
G. L. Rock ◽  
J. B. Stothers
Keyword(s):  
Magnetic Resonance ◽  
Biosynthetic Pathway ◽  
Nuclear Overhauser Effect ◽  
Difference Spectra ◽  
Heteronuclear Correlation ◽  
Magnetic Resonance Studies ◽  
Overhauser Effect ◽  
Effect Difference ◽  
Nuclear Overhauser ◽  
Magnetic Resonance Spectra

A tricyclic diene, traversiadiene, isolated from cultures of Cercosporatraversiana has been shown to have the structure and stereochemistry of the previously postulated hydrocarbon intermediate on the biosynthetic pathway to traversianal (1). Detailed:1H and 13C magnetic resonance studies, including homo- and heteronuclear correlation spectra, led to the gross structure, and the stereochemistry was established through a series of nuclear Overhauser effect difference spectra. Keywords: diterpene, traversiadiene, 1H and 13C magnetic resonance spectra.

Determination of configuration and conformation of isoxazolidines by nuclear Overhauser effect difference spectroscopy

1982 ◽  
Vol 47 (23) ◽  
pp. 4397-4403 ◽  
Author(s):  
Philip DeShong ◽  
C. Michael Dicken ◽  
Ronald R. Staib ◽  
Alan J. Freyer ◽  
Steven M. Weinreb
Keyword(s):  
Nuclear Overhauser Effect ◽  
Difference Spectroscopy ◽  
Overhauser Effect ◽  
Effect Difference ◽  
Nuclear Overhauser ◽  
Configuration And Conformation

A proton magnetic resonance nuclear Overhauser enhancement study. Application to vitamin D derivatives D2 and D3

1980 ◽  
Vol 58 (12) ◽  
pp. 1206-1210 ◽  
Author(s):  
George Kotovych ◽  
Gerdy H. M. Aarts ◽  
Klaus Bock
Keyword(s):  
Conformational Equilibrium ◽  
Nuclear Overhauser Effect ◽  
Coupling Constants ◽  
Nuclear Overhauser Enhancement ◽  
Conformational Interconversion ◽  
Overhauser Effect ◽  
Effect Difference ◽  
Nuclear Overhauser ◽  
Unambiguous Assignment ◽  
Study Application

Nuclear Overhauser effect difference experiments on vitamins D2 and D3 at 400 MHz allow an unambiguous assignment to be made for the HE and HZ protons bonded to the C-19 carbon. This assignment is especially important since the A ring, and hence the C-19 atom, undergoes a conformational interconversion. The results indicate the importance of proton nOe difference experiments in determining points of configuration and they indicate that the assignment of resonances based on allylic coupling constants in a molecule undergoing a conformational equilibrium can be incorrect.

The isolation and structural elucidation of a new iridoid glycoside from Cymbaria dahurica L.

2018 ◽  
Vol 73 (6) ◽  
pp. 377-379 ◽  
Author(s):  
Cui-Lan Bai ◽  
Qing-Hu Wang ◽  
Yan-Hua Xu ◽  
Jun-Sheng Han ◽  
Yin-Ping Bao
Keyword(s):  
Quantum Coherence ◽  
Nuclear Overhauser Effect ◽  
Multiple Bond ◽  
2D Nmr ◽  
Iridoid Glycoside ◽  
Correlation Spectroscopy ◽  
Etoac Extract ◽  
Overhauser Effect ◽  
Nuclear Overhauser ◽  
C Nmr

AbstractA new iridoid glycoside, namely, cymdahoside A (1), together with two known ones, 2 and 3, were isolated from the EtOAc extract of Cymbaria dahurica. The structure elucidation of 1 was carried out by one-dimensional (1D) NMR (1H and 13C NMR) and 2D NMR (correlation spectroscopy, heteronuclear single-quantum coherence, heteronuclear multiple-bond correlation and nuclear Overhauser effect spectroscopy) spectral analyses.

Determination of the stereochemistry of isoxazolidinium salts by nuclear Overhauser effect difference spectroscopy

1988 ◽  
Vol 26 (11) ◽  
pp. 974-979 ◽  
Author(s):  
A. Liguori ◽  
R. Ottanà ◽  
G. Romeo ◽  
E. Rotondo ◽  
G. Sindona ◽  
...  
Keyword(s):  
Nuclear Overhauser Effect ◽  
Difference Spectroscopy ◽  
Overhauser Effect ◽  
Effect Difference ◽  
Nuclear Overhauser

The structure, stereochemistry, and biosynthetic origin of a diterpenoid fungal metabolite, traversianal, established by 1H, 2H, and 13C magnetic resonance

1988 ◽  
Vol 66 (5) ◽  
pp. 1084-1090 ◽  
Author(s):  
Albert Stoessl ◽  
G. L. Rock ◽  
J. B. Stothers ◽  
R. C. Zimmer
Keyword(s):  
Magnetic Resonance ◽  
Nuclear Overhauser Effect ◽  
Acetate Incorporation ◽  
Fungal Metabolite ◽  
Difference Spectra ◽  
Methyl Group ◽  
Heteronuclear Correlation ◽  
Overhauser Effect ◽  
Effect Difference ◽  
Nuclear Overhauser

The structure of traversianal, a tricyclic diterpenoid fungal metabolite of Cercospora traversiana, has been elucidated through detailed 1H and 13C magnetic resonance studies, including homo- and heteronuclear correlation spectra of the natural product and examination of 13C-labelled material obtained by [1,2-13C2]acetate incorporation experiments. Its stereochemistry was established from a series of nuclear Overhauser effect difference spectra. The tricyclic carbon skeleton of traversianal is that of the fusicoccin/cotylenin and ophiobolane terpenes although the oxygenation pattern closely resembles the latter. Incorporation experiments with [2,2,2-2H3, 1-13C1]acetate revealed that traversianal arises by a sequence that differs substantially from that established for the fusicoccanes but rather resembles that previously shown for the ophiobolanes, in the retention of hydride at C-2, -10, and -14. However, the opposite configuration of the methyl group at C-3 suggests that the route to traversianal involves a terminal trans-geranylgeranyl unit instead of the cis unit implicated in ophiobolin generation.

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