S. Chidangil et al., A MOLECULAR ELECTROSTATIC POTENTIAL MAPPING STUDY OF SOME FLUOROQUINOLONE ANTIBACTERIAL AGENTS, JOURNAL OF MOLECULAR MODELING, 4(8), 1998, pp. 250-258
Molecular electrostatic potential (MEP) maps of some fluoroquinolones
having varying degrees of activity against the bacterium Staphylococcu
s Aureus have been studied using the optimized hybridization displacem
ent charges (HDC) combined with Lowdin charges obtained by the AM1 met
hod. The roles of different substitutions at the N-1-position in the p
arent quinolone ring have been studied. The conformation of the carbox
ylic group attached to the quinolone ring was shown to be such that th
ere is an intramolecular hydrogen bonding between the hydrogen atom of
this group and the oxygen atom of the carbonyl group of the quinolone
moiety. The carbonyl oxygen atom of the quinolone moiety, hydroxyl ox
ygen atom of the carboxylic group and the terminal nitrogen atom of th
e piperazin ring attached to the quinolone ring appear to be involved
in the action of the drugs through electrostatic interactions while th
e N-1-alkyl substituents seem to be involved in the same through hydro
phobic interactions.