Theoretical Studies of Stability, and Local Molecular Properties of Allopurinol Isomers by Density Functional Theory
N. Surendra Babu, Sisay Tadeasse, T. A. Lelisho, Nimmagadda Padmaja
Density functional theory (DFT) were used to determine the relative energies, electronegativity(χ), hardness (η), softness(S), electrophilicity index (ω) and local reactivity descriptors such as Fukui function, for the Allopurinol isomers (A1, A2, A3, A4, A5 and A6). For this purpose, the DFT/B3LYP method, with the 6-311++G (d,p) basis set was utilized. The local reactivity has been analyzed through the condensed Fukui function using natural population analysis (NPA). The most stable isomer is A5 and A1 has lowest energy, with relative energy about 5.97 kcal mol-1 and other four isomers (A2, A3, A4 and A6) have highest energy, with relative energy about 11.58-37.40 kcal mol-1. On the frontier orbital energy gap, the reactivity order of the isomers are A1 > A4 > A5 > A3 > A2 > A6 respectively. The preferred site for nucleophilic attack, and electrophilic in all isomers are N3, N8, N8, N3, O1 and N5, C2, N9, N9, N9, C9, and N6, for the isomers A1, A2, A3, A4, A5, and A6 respectively.
Allopurinol, DFT, HOMO-LUMO, Hardness, Softness, Fukui Function
Cite This Article
N. Surendra Babu, Sisay Tadeasse, T. A. Lelisho, Nimmagadda Padmaja. (2014). Theoretical Studies of Stability, and Local Molecular Properties of Allopurinol Isomers by Density Functional Theory. International Journal for Pharmaceutical Research Scholars, 3(1), 557-565.