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Prediction of tautomeric preferences and p K a values for oxyluciferin and its constituent heterocycles
Author(s) -
Dahlke Erin E.,
Cramer Christopher J.
Publication year - 2003
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.634
Subject(s) - tautomer , chemistry , computational chemistry , aqueous solution , stereochemistry
Well converged electronic structure calculations are employed to predict the relative energies of tautomers of thiazol‐5(4 H )‐one/5‐hydroxythiazole. Benchmarks established for this system are then employed to correct less complete levels of theory applied to the prediction of relative tautomer energies in substituted cases, including oxyluciferin. In the gas phase and aqueous solution, weak preferences for hydroxy and keto tautomers, respectively, are generally observed, but the magnitude is such that mixtures containing significant quantities of minor tautomers are predicted in most instances. The first p K a value for oxyluciferin is predicted to be 6.5, with phenolate tautomers dominating the anionic equilibrium. Copyright © 2003 John Wiley & Sons, Ltd.