Determination of deuterium fraction in heavy water by proton chemical shifts

1979 ◽  
Vol 51 (8) ◽  
pp. 1335-1336
Author(s):  
Aarre. Kellomaki ◽  
Mirjami. Jutila
Keyword(s):  
Heavy Water ◽  
Chemical Shifts ◽  
Proton Chemical Shifts

1H Chemical Shifts of Protons Directly Bonded to Phosphorus

1970 ◽  
Vol 25 (5) ◽  
pp. 451-461 ◽  
Author(s):  
Doureid Houalla ◽  
Raymond Marty ◽  
Robert Wolf
Keyword(s):  
Chemical Shifts ◽  
Proton Chemical Shifts

Over 100 δH values of H- (P) obtained in our laboratory, as well as values from the literature, have been tabulated and discussed. These data are useful, not only in the study of molecules containing a P-H bond but also, more generally, in the determination of the factors which influence the value of proton chemical shifts.

scholarly journals Stereochemical Determination of Fistularins Isolated from the Marine Sponge Ecionemia acervus and Their Regulatory Effect on Intestinal Inflammation

Marine Drugs ◽  
2021 ◽  
Vol 19 (3) ◽  
pp. 170
Author(s):  
Yeong Kwang Ji ◽  
Seon Min Lee ◽  
Na-Hyun Kim ◽  
Nguyen Van Tu ◽  
Yun Na Kim ◽  
...  
Keyword(s):  
Marine Sponge ◽  
Intestinal Inflammation ◽  
Nuclear Translocation ◽  
Chemical Shifts ◽  
Stereochemical Structure ◽  
Mapk Phosphorylation ◽  
Tnf Α ◽  
Inflammatory Bowel ◽  
Proton Chemical Shifts

By activity-guided fractionation based on inhibition of nitric oxide (NO) and prostaglandin E2 (PGE2), six fistularin compounds (1–6) were isolated from the marine sponge Ecionemia acervus (order Astrophorida). Based on stereochemical structure determination using Mosher’s method, fistularin-3 was assigned as a new stereoisomer. On the basis of the stereochemistry of fistularin-3, the stereochemical homogeneity of all six compounds was established by comparing carbon and proton chemical shifts. For fistularin-1 (1) and -2 (2), quantum calculations were performed to confirm their stereochemistry. In a co-culture system of human epithelial Caco-2 cells and THP-1 macrophages, all six isolated compounds showed potent anti-inflammatory activities. These bioactive fistularins inhibited the production of NO, PGE2, TNF-α, IL-1β, and IL-6 induced by lipopolysaccharide and interferon gamma. Inducible NO synthase and cyclooxygenase-2 expression and MAPK phosphorylation were downregulated in response to the inhibition of NF-κB nuclear translocation. Among the compounds tested, fistularin-1 (1) and 19-deoxyfistularin-3 (4) showed the highest activity. These findings suggest the potential use of the marine sponge E. acervus and its metabolites as pharmaceuticals for the treatment of inflammation-related diseases including inflammatory bowel disease.

NUCLEAR MAGNETIC RESONANCE STUDIES: VIII. DETERMINATION OF THE THERMODYNAMIC PARAMETERS GOVERNING ASSOCIATIONS OF SUBSTITUTED BENZALDEHYDES IN TOLUENE SOLUTION

1966 ◽  
Vol 44 (1) ◽  
pp. 37-44 ◽  
Author(s):  
R. E. Klinck ◽  
J. B. Stothers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Temperature Dependence ◽  
Chemical Shifts ◽  
Toluene Solution ◽  
Kcal Mole ◽  
Magnetic Resonance Studies ◽  
Substituted Benzaldehydes ◽  
Proton Chemical Shifts

The temperature dependence of the proton chemical shifts of four substituted benzaldehydes in toluene solution has been measured. From these results, estimates have been made of the enthalpies and entropies of formation of the stereospecific solute–solvent complexes which were previously shown to exist in these systems. These calculations indicate that the ΔH and ΔS values are −0.9 ± 0.2 kcal/mole and −4.9 ± 1.3 e.u., respectively. No correlation with substitution is apparent; the results are compared with other available data.

Carbon-13 and nitrogen-14 NMR spectra of 1-(substituted phenyl)pyridinium salts

1980 ◽  
Vol 45 (10) ◽  
pp. 2766-2771 ◽  
Author(s):  
Antonín Lyčka
Keyword(s):  
Heavy Water ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Pyridinium Salts ◽  
Nmr Signals ◽  
C Nmr

The 13C and 14N NMR spectra of 1M solutions of 1-(substituted phenyl)pyridinium salts (4-CH3, 4-OCH3, H, 4-Cl, 4-Br, 4-I, 3-NO2, 4-NO2, 2,4-(NO2)2 (the 13C NMR only)) have been measured in heavy water at 30 °C. The 13C and 14N chemical shifts, the 1J(CH) coupling constants, some 3J(CH) coupling constants, and values of half-widths Δ 1/2 of the 14N NMR signals are given. The 13C chemical shifts of C(4) correlate with the σ0 constants (δC(4) = (1.79 ± 0.097) σ0 + (147.67 ± 0.041)), whereas no correlation of the nitrogen chemical shifts with the σ constants has been found. The half-widths Δ 1/2 correlate with the σ0 constants (Δ 1/2 = (76.2 ± 4.9) σ0 + (106.4 ± 2.2)) except for 1-phenylpyridinium chloride.

Gradient-Enhanced Inverse-Detected NMR Techniquesfor Determination of 1H-15N Coupling Constants in 2,2-Dimethylpenta-3,4-dienal Derivatives

1997 ◽  
Vol 62 (11) ◽  
pp. 1747-1753 ◽  
Author(s):  
Radek Marek
Keyword(s):  
Double Bond ◽  
Chemical Shifts ◽  
Multiple Bond ◽  
Coupling Constants ◽  
Single Quantum ◽  
Nmr Techniques ◽  
Phase Sensitive ◽  
Heteronuclear Coupling

Determination of 15N chemical shifts and heteronuclear coupling constants of substituted 2,2-dimethylpenta-3,4-dienal hydrazones is presented. The chemical shifts were determined by gradient-enhanced inverse-detected NMR techniques and 1H-15N coupling constants were extracted from phase-sensitive gradient-enhanced single-quantum multiple bond correlation experiments. Stereospecific behaviour of the coupling constants 2J(1H,15N) and 1J(1H,13C) has been used to determine the configuration on a C=N double bond. The above-mentioned compounds exist predominantly as E isomers in deuteriochloroform.

Sign in / Sign up

Export Citation Format

Share Document