rates of acid-catalyzed nh proton exchange of enaminones, an 1h nmr study

: 1h 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.