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Chemical isomerism characterized by facile interconversion of isomeric forms in equilibrium, especially by migration of a hydrogen atom.

tau′to·mer (tô′tə-mər) n.
tau′to·mer′ic (tô′tə-mĕr′ĭk) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Elements & Compounds) either of the two forms of a chemical compound that exhibits tautomerism
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
References in periodicals archive ?
Only its Enol tautomer qualifies it to be a UVA filter with a [lambda]max of 357nm.
The minimized internal energies (total energy and binding energy) beside the formation energy (Tables 1 and 2) of 21 tautomers suggest their high stability which outweigh their production from the coupling reaction and indicate that the most stable tautomer is 21A.
Dziembowska et al., "Keto-enol tautomerism of two structurally related Schiff bases: Direct and indirect way of creation of the excited keto tautomer," Chemical Physics Letters, vol.
As a [beta]-diketone, curcumin also exists as a keto-enol tautomer that chelates transition metal ions with high affinity.
Using Pipeline Pilot of SciTegic to enumerate the tautomer, stereoisomers and protonation/deprotonation form at pH 7.4 of the active and decoy compounds.
Principle: Creatinine in alkaline medium reacts with picric acid to form a red tautomer of creatinine picrate, the intensity of which is measured by colorimeter at 520nm.
In deuterated acetone, regioisomer 14aS is mainly present as the thioxo tautomer II whose proton signals are downfield shifted with respect to tautomer I in nice keeping with the observations reported in literature for thiopurine derivatives [28].
The resulting 2-hydroxychromanone then may be in equilibrium with its tautomer, 2,4-dihydrochromene.
Therefore, we considered the additional two models of the dissociated (Figure 3(b), Scheme 2) and tautomer (Figure 3(c), Scheme 2) states and calculated the frequencies of these two models which are shown in Tables 3 and 4.
However, the predominant keto-enol tautomer in aprotic/apolar solvent exhibited an absorption peak at 420 nm [20].
[sup.1]H-NMR Spectra: In the [sup.1]H-NMR spectra of triazolothiadiazines (III), the characteristic downfield signal at [delta] 8.70 ppm attributed to the -N=C-SH (-NH-C=S of the tautomer) in compound II is present, as is a sharp signal at [delta] 7.32 ppm attributable to the N-N[H.sub.2] group in the parent triazole [14].