Structure of the antiviral stavudine using quantum chemical methods: Complete conformational space analysis, 3D potential energy surfaces and solid state simulations

Conformational Analysis, Molecular Structure and Solid State Simulation of the Antiviral Drug Acyclovir (Zovirax) Using Density Functional Theory Methods

“…It is because of the small difference in energy between both forms A1 and B2 . This global minimum in the syn form by MP2 is in accordance to that obtained in other nucleosides [ 33 , 34 , 35 ] but differs of the anti form expected for the natural nucleosides and nucleotides in biological systems [ 43 ]. The second most stable conformer is B1 with values of φ 1 = 70°, φ 2 = −152° and φ 3 = 94° by MP2.…”

“…DFT methods provide adequate compromise between the desired accuracy and the heavy demands put on computer time and power. Different studies have shown that the data obtained with DFT methods are in good agreement with those obtained by expensive computational methods as MP2 [31,32,33,34,35]. Also they give good results in many studies on nucleosides and on drug design [36,37] and they predict vibrational frequencies of DNA bases better than HF and MP2 [38,39,40,41,42].…”

“…By the same methodology, the relative energies of the different conformers have been determined in related nucleosides [ 34 , 46 , 47 , 48 ]. The global minimum calculated in these molecules by MP2/6-31G(d,p) was in accordance to that found by B3LYP/6-31G(d,p).…”

FT-IR spectra of the anti-HIV nucleoside analogue d4T (Stavudine). Solid state simulation by DFT methods and scaling by different procedures

“…In a previous study, and through 3D potential energy surface, 25 local minimum by MP2 and several DFT methods were determined [20]. From them, the three most stable conformers in the biological active anti-form are plotted in Fig.…”

“…Many studies related to the activity of d4T [16] as compared with other prodrugs have been reported [17][18][19], but little appears on the structure and spectroscopy of this compound. For this purpose, in a previous study the conformational analysis of the d4T structure [20] and other related prodrugs were carried out using MP2 and DFT methods [21][22][23]. However, the assignments of all the fundamental vibrations of the experimental spectra have not yet been reported, highlighting the importance of the present study.…”