Tautomerism and acidity in 4-quinolone-3-carboxylic acid derivatives

Article abstract of DOI:10.1016/S0040-4020(01)89860-4

Prototropic tautomerism in 4-quinolone-3-carboxylic acid derivatives has been studied with particular emphasis on the influence of the ring substituents on the equilibrium. The techniques used include UV, ¹H-NMR, ¹³C-NMR (solution and ¹³C-NMR CP/MAS (solid state) and semiempirical and ab initio calculations. The pK_a values of some quinolone derivatives have been determined and correlated with data obtained from semiempirical methods.