Energetic Study of 4(3H)-Pyrimidinone: Aromaticity of Reactions, Hydrogen Bond Rules, and Support for an Anomeric Effect

• Type: Article in International Scientific Journal
• Date: 2014

Authors

Tiago L P Galvao (Author) Other; Ines M Rocha (Author) Other; Maria D M C R Ribeiro da Silva (Author) FCUP; Manuel A V R Ribeiro da Silva (Author) Other

Journal

Title: Journal of Physical Chemistry A

Vol. 118

Pages: 3360-3366

ISSN: 1089-5639

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 10 Citations

Scopus - 10 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-009-DNB

DOI: 10.1021/jp502468s

Abstract (EN): 4(3H)-Pyrimidinone is observed in nature in equilibrium with other tautomeric forms, mimicking the tautomeric equilibrium in pyrimidine nucleobases. In this work, the enthalpy of formation in the gaseous phase of 4(3H)-pyrimidinone was derived from the combination of the enthalpy of formation in the crystalline phase, obtained by static bomb combustion calorimetry, and the enthalpy of sublimation, obtained by Knudsen effusion. The gaseous phase enthalpy of formation of 4(3H)-pyrimidinone was interpreted in terms of isodesmic reactions that consider the enthalpic effects of hydroxypyridines and pyrimidine. After comparison of the experimental and computational results, the same type of isodesmic reactions was used to study the substituent effects of the hydroxyl functional group of 2-, 4-, and 5-hydroxypyrimidines. The influence of aromaticity on the energetics of hydroxypyrimidines was evaluated using the variation of nucleus-independent chemical shifts for several reactions. The influence of intramolecular hydrogen bonds was investigated using the quantum theory of atoms in molecules and the geometric rule of Baker and Hubbard to identify hydrogen bonds. The energetic results obtained were also interpreted in terms of an in plane anomeric effect in the pyrimidine ring.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7