TITLE:
Theoretical Study by Density Functional Theory Method (DFT) of Stability, Tautomerism, Reactivity and Prediction of Acidity of Quinolein-4-One Derivatives
AUTHORS:
Affoué Lucie Bédé, Amon Benjamine Assoma, Kicho Denis Yapo, Mamadou Guy-Richard Koné, Soleymane Koné, Mawa Koné, Boka Robert N’Guessan, El-Hadji Sawaliho Bamba
KEYWORDS:
Quinolein-4-One, Tautomers, Equilibrium Constants, Global Descriptors, Dual Descriptors
JOURNAL NAME:
Computational Chemistry,
Vol.6 No.3,
July
25,
2018
ABSTRACT: A theoretical study of the reactivity of quinoline-4-one derivatives is undertaken
in order to understand the involved mechanisms. The calculations were
carried out in gas phase and in N, N-Dimethylformamide (DMF) solution.
The Density Functional Theory (DFT) with B3LYP functional associated to
6-311G (d) and 6-311+G (d) bases is used to perform these calculations. The
results of the thermodynamic parameters showed that there is an equilibrium
relation between the different tautomers. This equilibrium can be used to explain
the failure to obtain tetrahydroquinoline from
5,8-dimethoxy-quinolin-4-one. Reactivity analysis from Frontier Molecular
Orbitals theory and Fukui function calculations revealed that ketone forms are
less reactive than enol ones. The methoxyl substituent decreases the acidity of
the nitrogen and oxygen atoms of quinolin-4-one while the bromine increases
the acidity of the same sites. These results foresee that nitrogen deprotonation
in the case of the brominated compound is easier than in the case of methoxylated
ones.