title: The keto-enol tautomerization of ethyl butylryl acetate studied by LC-NMR.
abstract: The keto-enol tautomerism of ethyl butylryl acetate was studied in mixed solvents under a variety of experimental conditions. The direct measurement of ketonization of the enol tautomer was performed by using the hyphenated technique LC-NMR. The keto and enol tautomers can be separated by using HPLC and their interconversion is a slow process on the NMR timescale. The ketonization reaction was found to be acid catalyzed and the solvent isotope effect, kH2O/kD2O, in an acetonitrile/water mixture, is 5.4. The ketonization rate constants were also measured at different compositions of binary solvents, such as CH3CN/D2O, CD3OD/D2O, and CH3CN/CD3OD. The rate constant and water percentage were found to have an exponential relationship. The reaction rate as a function of solvent polarity will be discussed in this paper.
authors.affiliation: D-R418, Structural Chemistry, Global Pharmaceutical Research and Development, Abbott Laboratories, North Chicago, IL 60064, USA. chun.zhou@abbott.com
authors.forename: Casey Chun
authors.initials: CC
authors.lastname: Zhou
authors.forename: David R
authors.initials: DR
authors.lastname: Hill