KETO–ENOL TAUTOMERISM IN β-DICARBONYLS STUDIED BY NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY: II. SOLVENT EFFECTS ON PROTON CHEMICAL SHIFTS AND ON EQUILIBRIUM CONSTANTS

Solvent Effects on Nuclear Magnetic Resonance

The known solvent dependence of J(Cc,Hf) and J(C1,Hf) couplings in acetaldehyde is studied from a theoretical viewpoint based on the density functional theory approach where the dielectric solvent effect is taken into account with the polarizable continuum model. The four terms of scalar couplings, Fermi contact, paramagnetic spin orbital, diamagnetic spin orbital and spin dipolar, are calculat...

Nuclear magnetic resonance spectroscopy. Ring-current effects on carbon-13 chemical shifts.

A comparison of the (13)C nuclear magnetic resonance chemical shifts of some 15,16-dialkyl-15,16-dihydropyrenes with the corresponding 15,16-dialkyl-2,7,15,16-tetrahydropyrenes provides a measure of the effect of ring current on carbon-13 chemical shifts in which other effects may be expected to be negligibly small. The general conclusion is that the absolute magnitude of the ring-current effec...

Proton Nuclear Magnetic Resonance Spectroscopy

Studies on Prototropic Tautomerism in Neutral and Monoanionic Forms of Pyrimidines by Nuclear Magnetic Resonance Spectroscopy

NMR methods have been applied to evaluation of prototropic tautomerism, N (1)H ^ N (3) H. in several selected pyrimidines, viz. the neutral forms of isocytosine and 2-alkylthiopyrimidone-4, and the monoanionic forms of uracil, 5-fluorouracil and 4-thiouracil. The predominant tautomeric species of the neutral forms could be estimated only qualitatively from chemical shifts. For the monoanionic f...

Rhabdomyolysis-related renal tubular damage studied by proton nuclear magnetic resonance spectroscopy of urine.