Synthesis and biological evaluation of novel isoxazole derivatives from acridone.

The present study was carried out in an attempt to synthesize a new class of potential antibacterial agents. In this context, novel isoxazoles were synthesized and evaluated for their potential antibacterial behavior against four pathogenic bacterial strains. The synthesized compounds exhibited moderate-to-good antibacterial activity against these strains. The highest antibacterial activity was observed against the Escherichia coli strains, particularly for compounds 4a and 4e with phenyl and para-nitrophenyl groups on the isoxazole-acridone skeleton; they showed promising minimum inhibitory concentration values of 16.88 and 19.01 µg/ml, respectively, compared with the standard drug chloramphenicol (22.41 µg/ml). The synthesized compounds were subjected to in silico docking studies to understand the mode of their interactions with the DNA topoisomerase complex (PDB ID: 3FV5) of E. coli. The molecular docking results showed that compounds 4a-l occupy the active site of DNA topoisomerase (PDB ID: 3FV5), stabilized via hydrogen bonding and hydrophobic interactions, which may be the reason behind their interesting in vitro antibacterial activity.

A highly turn-on fluorescent CHEF-type chemosensor for selective detection of Cu2+ in aqueous media.

An efficient "turn on" fluorescence chemosensor Schiff base LH based on the combination of 2-Hydroxy-5-(p-tolyldiazenyl)benzaldehyde and N-(3-Aminopropyl)imidazole was prepared and characterized then evaluated for its selective fluorescent sensing of Cu2+ amongst other metal ions. The CN isomerization inhibition process induced by the Cu2+ binding warrants the chelation-induced enhanced fluorescence (CHEF) effect. In addition, the detection limit sensing of LH for Cu2+ was found to be 1.8 × 10-6 M that is below the WHO recommendation level (20 µM) for drinking water.

Copper(II)/H(2)O(2)-mediated DNA cleavage: involvement of a copper(III) species in H-atom abstraction of deoxyribose units.

A new bis-amido-copper(II) complex 2 has been prepared. In the presence of reducing agents (ascorbate or DTT) under air atmosphere or hydrogen peroxide, complex 2 exhibited interesting nuclease activities in the 1-10 microM concentration range. For explaining the activity observed with hydrogen peroxide, we propose the occurrence of a bis-amido-copper(III) intermediate and an oxidation mechanism involving a H-atom abstraction of deoxyribose moieties of DNA.