Intramolecular Specific Interaction C-H···O in 1-Vinyl-5-pyrazolecarboxylic Acid Revealed by ~1H NMR Spectroscopy Data

摘要

The presence of intramolecular hydrogen bond C— H···N in 2-vinyloxy(vinylthio)pyridine and 2-vinyloxy (vinylthio)quinoline was shown earlier [1]. Structural studies of a wide series of vinylimidazoles on the basis of ~1H and ~(13)C NMR spectroscopy revealed the presence of intramolecular specific interactions (ISI) C-H···N in some molecules [2-4]. By the ~1H and ~(13)C NMR spectra data, the intramolecular specific interactions, namely, the weak hydrogen bonds of the C-H···O type between vinyl α-proton and carbonyl oxygen atom occur also in 1-vinyl-2-formylimidazole and 1-vinyl-2-formylbenzimidazole [5].