Please use this identifier to cite or link to this item: https://doi.org/10.1021/jo0266792
Title: Tautomeric equilibria of pyridoxal-5′-phosphate (vitamin B6) and 3-hydroxypyridine derivatives: A theoretical study of solvation effects
Authors: Kiruba, G.S.M. 
Wong, M.W. 
Issue Date: 4-Apr-2003
Source: Kiruba, G.S.M., Wong, M.W. (2003-04-04). Tautomeric equilibria of pyridoxal-5′-phosphate (vitamin B6) and 3-hydroxypyridine derivatives: A theoretical study of solvation effects. Journal of Organic Chemistry 68 (7) : 2874-2881. ScholarBank@NUS Repository. https://doi.org/10.1021/jo0266792
Abstract: The tautomeric equilibria of a series of 3-hydroxypyridine derivatives including pyridoxal-5′-phosphate (PLP), the active form of vitamin B6, have been studied using density functional calculations (B3LYP/6-311+G**//B3LYP/6-31G*) in the gas phase and in different solvents. Three different approaches, namely continuum, discrete, and hybrid (combined discrete/SCRF), were employed to investigate the effects of solvation on the tautomeric equilibria. In all cases, the neutral hydroxy form is significantly more stable than the zwitterionic oxo form (by 43-56 kJ mol-1) in the gas phase. The tautomeric energies reduce substantially in the presence of a polarizable dielectric medium. However, the neutral form is calculated to be the dominant form in nonpolar and aprotic polar solvents. On the other hand, a reversal of tautomeric equilibrium, in favor of the zwitterionic form, is predicted in an aqueous medium. This study highlights the role of both water molecules and bulk solvent effect in influencing the tautomeric equilibria of the PLP related compounds. A combination of explicit microsolvation and continuum reaction field is required to account fully for the energetic effect of aqueous solvation. The tautomeric free energy differences (δG298) of PLP in the gas phase and in aprotic polar (ε = 40) and aqueous media are predicted to be 47, 22, and -29 kJ mol-1, respectively.
Source Title: Journal of Organic Chemistry
URI: http://scholarbank.nus.edu.sg/handle/10635/95196
ISSN: 00223263
DOI: 10.1021/jo0266792
Appears in Collections:Staff Publications

Show full item record
Files in This Item:
There are no files associated with this item.

SCOPUSTM   
Citations

25
checked on Feb 20, 2018

WEB OF SCIENCETM
Citations

23
checked on Nov 19, 2017

Page view(s)

17
checked on Feb 24, 2018

Google ScholarTM

Check

Altmetric


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.