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1 H and 13 C NMR study of the enol–enolic tautomerism of some cyclic β‐ketoaldehydes
Author(s) -
Shapet'ko N. N.,
Radushnova I. L.,
Bogachev Yu. S.,
Berestova S. S.,
Potapov V. M.,
Kiryuschkina G. V.,
Talebarovskaya I. K.
Publication year - 1975
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270071104
Subject(s) - tautomer , chemistry , chemical shift , enol , aldehyde , enthalpy , keto–enol tautomerism , ketone , computational chemistry , stereochemistry , organic chemistry , physics , thermodynamics , catalysis
Aldehyde (δCH) and enolic (δOH) proton chemical shifts, the corresponding spin–spin coupling constants ( J CH,OH) and the 13 C chemical shifts (δC) have been measured for three cyclic β‐ketoaldehydes as a function of temperature. A tautomeric equilibrium has been shown to exist between the aldo–enol ( A ) and hydroxymethylene ketone ( B ) forms. The chemical shifts δCH δOH and δC for the two pure tautomeric forms A and B have been calculated. The enthalpy changes Δ H in the tautomeric process A ⇄ B and the percentages of the tautomeric forms have been determined.