Premium
Keto–enol tautomerism in β‐ketoesters: CH 3 C(O)CHXC(O)OY (X = H, Cl; Y = CH 3 , C 2 H 5 ). Vibrational analyses, NMR spectra and quantum chemical calculations
Author(s) -
Schiavoni M. M.,
Di Loreto H. E.,
Hermann A.,
Mack H.G.,
Ulic S. E.,
Della Védova C. O.
Publication year - 2001
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.701
Subject(s) - tautomer , chemistry , enol , raman spectroscopy , ab initio , density functional theory , keto–enol tautomerism , ab initio quantum chemistry methods , infrared spectroscopy , nmr spectra database , fourier transform infrared spectroscopy , spectroscopy , crystallography , spectral line , stereochemistry , computational chemistry , molecule , catalysis , organic chemistry , physics , quantum mechanics , astronomy , optics
Abstract The tautomeric equilibria of the β‐ketoesters [CH 3 C(O)CH 2 C(O)OCH 3 ( I ), CH 3 C(O)CHClC(O)OCH 3 ( II ), CH 3 C(O)CH 2 C(O)OCH 2 CH 3 ( III ) and CH 3 C(O)CHClC(O)OCH 2 CH 3 ( IV )] were studied by NMR spectroscopy and, in the case of I and II , by quantum chemical calculations ( ab initio and density functional methods). In addition, liquid‐state Fourier transform infrared and Raman spectra were analysed for all four compounds. They revealed the existence of two tautomers, diketo and enol forms. In the NMR spectra only signals for the diketo form could be observed for I and III . However, the calculations for I and II predicted the enol structures to be the most stable species. Copyright © 2001 John Wiley & Sons, Ltd.