Rates of Acid-Catalyzed NH Proton Exchange of Enaminones, an 1H NMR Study

Abstract

: <em>¹</em><em>H NMR spectra of a series of enaminones R-CO-CH=C(NHCH₂Ph)-R [1, R=CH₃; 2, R=C₆H₅; 3, R=CF₃; 4, R=CH₂CH₂CH₂; 5, R=CH₂C(CH₃)₂CH₂], were obtained in the presence of trifluoroacetic acid in CDCl₃ or DMSO-d₆ at 28 °C. Steric, solvent, electronic and hydrogen bonding effects on the rates of acid-catalyzed NH proton exchanges were investigated. Rate constants were calculated by ¹H NMR line shape analysis.</em>