sbornik_s_2011.pdf

XI. Workshop of Physical Chemists and Electrochemists´11 Brno
THE SPECTROSCOPIC STUDY OF
PHOTOINDUCED REACTIONS OF N-
HETEROCYCLIC COMPOUNDS
Miroslava BOBENIČOVÁ 1 , Jana TABAČIAROVÁ 1 , Kristína PLEVOVÁ 2 , Dana
DVORANOVÁ 1
1 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
2 Institute of Organic Chemistry, Catalysis and Petrochemistry, Faculty of Chemical and Food Technology,
Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37 Bratislava, Slovak Republic
Abstract
The work is focused on the photochemical transformation of novel fluoroquinolones in
aprotic media by means of UV-Vis spectroscopy and EPR spin trapping technique.
Investigated molecules behave as photosensitizers and UVA irradiation in the presence of
air led to the formation of reactive oxygen species.
1. INTRODUCTION
N-Heterocyclic compounds, mainly quinoline derivatives, are known for their
importance in therapeutical treatment. Although these substances contain basic quinoline
skeleton, their biological activity depends on their substitution character and position.
The 4-oxoquinoline derivatives represent one of the largest classes of antimicrobial agents
and they are known for their inhibition of Topoisomerase II. From them, the 4oxoquinoline
derivatives possessing a fluorine atom at position 6 as a substituent have
been classified as most efficient in biological activity [1,2]. The molecules contain
extended π-electron system which could be activated by UVA irradiation and molecules
could behave as photosensitizers. The photoactivation in the presence of oxygen leads to
the formation of reactive oxygen species (ROS) as superoxide radical anion, singlet oxygen
or hydroxyl radical [3,4], which could activated the undesirable side reactions, frequently
coupled with drop of biological activity of drug. Our study was focused on novel
fluoroquinolnoes (Table 1) with main attention on their photochemical transformation
using EPR and UV-Vis spectroscopy.
Tab. 1: Structures of investigated fluoroquinolones
F
O
N
R2
R1
- 49 -
R1 R2
F7Q2 COOC2H5 H
F7Q3 COOCH3 H
F7Q4 COOH H
F7EQ2 COOC2H5 C2H5