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1H and 13C NMR study of the enol–enolic tautomerism of some cyclic β-ketoaldehydes

✍ Scribed by N. N. Shapet'ko; I. L. Radushnova; Yu. S. Bogachev; S. S. Berestova; V. M. Potapov; G. V. Kiryuschkina; I. K. Talebarovskaya

Publisher
John Wiley and Sons
Year
1975
Tongue
English
Weight
268 KB
Volume
7
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

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.

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