title: Conformational, spectroscopic, and molecular dynamics DFT study of precursors for new potential antibacterial fluoroquinolone drugs.
abstract: Biological activity, functionality, and synthesis of (fluoro)quinolones is closely related to their precursors (for instance 3-fluoroanilinoethylene derivatives) (i.e., their functional groups, conformational behavior, and/or electronic structure). Herein, the theoretical study of 3-fluoroanilinoethylene derivatives is presented. Impact of substituents (acetyl, methyl ester, and ethyl ester) on the conformational analysis and the spectral behavior is investigated. The B3LYP/6-311++G** computational protocol is utilized. It is found that the intramolecular hydrogen bond N-H···O is responsible for the energetic preference of anti (a) conformer (anti position of 3-fluoroanilino group with respect to the C═C double bond). The Boltzmann ratios of the conformers are related to the differences of the particular dipole moments and/or their dependence on the solvent polarity. The studied acetyl, ethyl ester, and methyl ester substituted fluoroquinolone precursors prefer in the solvent either EZa, ZZa, or both conformers equally, respectively. In order to understand the degree of freedom of rotation of the trans ethyl ester group, B3LYP/6-311G** molecular dynamic simulations were carried out. Vibrational frequencies, electron transitions, as well as NMR spectra are analyzed with respect to conformational analysis, including the effect of the substituent. X-ray structures of the precursors are presented and compared with the results of the conformational analysis.
authors.affiliation: Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava , Radlinského 9, SK-812 37 Bratislava, Slovak Republic.
authors.forename: Sandra
authors.initials: S
authors.lastname: Dorotíková
authors.forename: Kristína
authors.initials: K
authors.lastname: Plevová
authors.forename: Lukáš
authors.initials: L
authors.lastname: Bučinský
authors.forename: Michal
authors.initials: M
authors.lastname: Malček
authors.forename: Peter
authors.initials: P
authors.lastname: Herich
authors.forename: Lenka
authors.initials: L
authors.lastname: Kucková
authors.forename: Miroslava
authors.initials: M
authors.lastname: Bobeničová
authors.forename: Stanislava
authors.initials: S
authors.lastname: Šoralová
authors.forename: Jozef
authors.initials: J
authors.lastname: Kožíšek
authors.forename: Marek
authors.initials: M
authors.lastname: Fronc
authors.forename: Viktor
authors.initials: V
authors.lastname: Milata
authors.forename: Dana
authors.initials: D
authors.lastname: Dvoranová
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004583:Electrons; D004952:Esters; D024841:Fluoroquinolones / Q000737:chemistry*; D006860:Hydrogen Bonding; D008968:Molecular Conformation; D013237:Stereoisomerism
chemical_list: D000900:Anti-Bacterial Agents; D004952:Esters; D024841:Fluoroquinolones