Biological evaluation of levofloxacin and its thionated derivatives: antioxidant activity, aldehyde dehydrogenase enzyme inhibition, and cytotoxicity on A549 cell line.

Levofloxacin (LVX) is among the fluoroquinolones antibiotics that has also been studied in vitro and in vivo for its anticancer effects. In this study, we used LVX and novel LVX thionated derivatives; compounds 2 and 3, to evaluate their antioxidant activity, aldehyde dehydrogenase (ALDH) enzymes activity inhibition, and anticancer activity. Combination treatments with doxorubicin (DOX) were investigated as well.

Design and Synthesis of Thionated Levofloxacin: Insights into a New Generation of Quinolones with Potential Therapeutic and Analytical Applications.

Levofloxacin is a widely used fluoroquinolone in several infectious diseases. The structure-activity relationship of levofloxacin has been studied. However, the effect of changing the carbonyl into thiocarbonyl of levofloxacin has not been investigated up to the date of this report.

Dual Function of β-Hydroxy Dithiocinnamic Esters: RAFT Agent and Ligand for Metal Complexation.

The reversible addition-fragmentation chain-transfer (RAFT) process has become a versatile tool for the preparation of defined polymers tolerating a large variety of functional groups. Several dithioesters, trithiocarbonates, xanthates, or dithiocarbamates have been developed as effective chain transfer agents (CTAs), but only a few examples have been reported, where the resulting end groups are directly considered for a secondary use besides controlling the polymerization. Herein, it is demonstrated that β-hydroxy dithiocinnamic esters represent a hitherto overlooked class of materials, which are originally designed for the complexation of transition metals but may as well act as reversible CTAs.

Novel [FeFe]-Hydrogenase Mimics: Unexpected Course of the Reaction of Ferrocenyl α-Thienyl Thioketone with Fe(CO).

The influence of the substitution pattern in ferrocenyl α-thienyl thioketone used as a proligand in complexation reactions with Fe(CO) was investigated. As a result, two new sulfur-iron complexes, considered [FeFe]-hydrogenase mimics, were obtained and characterized by spectroscopic techniques (H, C{H} NMR, IR, MS), as well as by elemental analysis and X-ray single crystal diffraction methods. The electrochemical properties of both complexes were studied and compared using cyclic voltammetry in the absence and in presence of acetic acid as a proton source.

Iron(0)-Mediated Stereoselective (3+2)-Cycloaddition of Thiochalcones via a Diradical Intermediate.

Reactions of α,β-unsaturated aromatic thioketones 1 (thiochalcones) with Fe (CO) leading to η -1-thia-1,3-diene iron tricarbonyl complexes 2, [FeFe] hydrogenase mimics 3, and the thiopyrane adduct 4 are described. Obtained products have been characterized by X-ray crystallography and by computational methods. Completely regio- and diastereoselective formation of the five-membered ring system in products 3, containing four stereogenic centers, can be explained by an unprecedented, stepwise (3+2)-cycloaddition of two thiochalcone molecules mediated by Fe (CO) .

[FeFe]-Hydrogenase H-Cluster Mimics with Various -S(CH)S- Linker Lengths (n = 2-8): A Systematic Study.

The effect of the nature of the dithiolato ligand on the physical and electrochemical properties of synthetic H-cluster mimics of the [FeFe]-hydrogenase is still of significant concern. In this report we describe the cyclization of various alkanedithiols to afford cyclic disulfide, tetrasulfide, and hexasulfide compounds. The latter compounds were used as proligands for the synthesis of a series of [FeFe]-hydrogenase H-cluster mimics having the general formulas [Fe(CO){μ-S(CH)S}] (n = 4-8), [Fe(CO){μ-S(CH)S}] (n = 6-8), and [Fe(CO){(μ-S(CH)S)}] (n = 6-8).

[FeFe]-Hydrogenase H-cluster mimics mediated by naphthalene monoimide derivatives of peri-substituted dichalcogenides.

Synthetic models of the active site of [FeFe]-hydrogenase containing naphthalene monoimide (NMI) of peri-substituted dichalcogenides as bridging linkers have been prepared and characterized using different spectroscopic methods. The influence of the imide functionality and the chalcogen atoms on the redox properties and the catalytic behaviour of complexes 7-10 was studied using cyclic voltammetry. The results revealed that the imide functionality has improved the chemical stability of the reduced species and the replacement of the S atoms by Se caused a cathodic shift in the oxidation peaks.

Selenium makes the difference: protonation of [FeFe]-hydrogenase mimics with diselenolato ligands.

The synthetic models of the active site of an [FeFe]-hydrogenase containing a Sn atom in the bridgehead of the diselenato ligand, namely [Fe(CO){μ-(SeCHSe)SnMe}], 3 and [Fe(CO){μ-(SeCH)SnMe}], 4 have been synthesized and characterized by different spectroscopic methods. The protonation properties of complex 4 have been investigated by monitoring the IR spectra in the carbonyl stretching region, H NMR in the hydride region as well as the Se{H} NMR upon addition of strong and moderate acids wherein the protonation of the active site of the [FeFe]-hydrogenase at one of its internal basic sites is considered an essential step in the catalytic cycle. Furthermore, we investigated the redox properties and the catalytic behaviour of complexes 3 and 4 in the presence of AcOH as a source of protons suggesting an ECE (E = electrochemical process, C = chemical process) mechanism.

[FeFe]-Hydrogenase H-Cluster Mimics with Unique Planar μ-(SCH ) ER Linkers (E=Ge and Sn).

Analogues of the [2Fe-2S] subcluster of hydrogenase enzymes in which the central group of the three-atom chain linker between the sulfur atoms is replaced by GeR and SnR groups are studied. The six-membered FeSCECS rings in these complexes (E=Ge or Sn) adopt an unusual conformation with nearly co-planar SCECS atoms perpendicular to the Fe-Fe core. Computational modelling traces this result to the steric interaction of the Me groups with the axial carbonyls of the Fe (CO) cluster and low torsional strain for GeMe and SnMe moieties owing to the long C-Ge and C-Sn bonds.