Carbon-13 magnetic resonance spectra of quaternary ammonium salts derived from enamino ketones

¹³C magnetic resonance spectra of nine quaternary ammonium salts of the general formula R¹C¹(O)C²H?C³HNR₃⁴Cl (where R¹, R⁴ = alkyl) were obtained and compared with those of the parent amino compounds. The chemical shift differences between these two classes of compounds are qualitatively accounted for by π-electron density changes. Steric effects and hyperconjugation of the alkyl substituents are also discussed.