3-Hydroxy-4-methyl-4-pentenonitrile and 4-methyl-3-oxo-4-pentenonitrile: Study of the tautomerics equilibria in gas phase and in solution

The 1H NMR spectra gave the additional evidence for the coexistence of the tautomers ketonitrile and enolnitrile for 4-methyl-3-oxo-4-pentenonitrile. The nitrile-ketenimine equilibrium for both compounds could not be observed by 1H NMR spectra because of the low sensibility of this method. The ketonitrile-enolnitrile tautomerization heat of 4-methyl-3-oxo-4-pentenonitrile has been calculated and compared with the corresponding one in gas phase to evaluate the solvent effect.