A DFT approach on tioguanine: Exploring tio-tiol tautomers, frontier molecular orbitals, IR and UV spectra, and quadrupole coupling constants
2021; Elsevier BV; Volume: 334; Linguagem: Inglês
10.1016/j.molliq.2021.116018
ISSN1873-3166
AutoresKun Harismah, Adil Muala Dhumad, Heba Salman Ibraheem, Hasan Zandi, Hatem Jameel Majeed,
Tópico(s)Synthesis and biological activity
ResumoTioguanine (TG) is a drug for medication of several types of cancers with favorable efficacy and unfavorable side effects. TG is a modification of guanine nucleobase including two fused heterocyclic rings easy for contributing to tautomerism mechanism, which was investigated in this work based on density functional theory (DFT) calculations. The tautomerism processes of tio-tiol conversion could show serious impacts on the expected function of TG, in which the results of this work indicated that such tautomers could be easily formed with small magnitude of switching energy between the tautomers. Frontier molecular orbitals analyses showed serious variations in the electronic features of TG molecules in tautomeric forms, in which the results were further described by the atomic scale quadrupole coupling constant (Qcc) evaluations. Although the switching energy was small enough to see all the tautomers in the same mode, but molecular and atomic scale features revealed different achievements for such systems as possible reasons of side effects arising during medications. As a final remark of this work, it could be mentioned that TG drug might be modified to show improved efficacies for the patients with lower side effect impacts; otherwise, the tautomeric processes could lead to existence of different side effects.
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