Synthesis, characterisation and antibacterial activity of substituted 2-quinoline thiosemicarbazones.

Abstract

Fifteen quinoline-2-thiosemicarbazone hybrid derivatives were synthesised in a three step reaction involving formation of the quinoline, oxidation of the 2-methyl group and condensation to the thiosemicarbazones. The phenylhydrazines were prepared in an additional step prior to the condensation. Twelve of the fifteen hybrid molecules were novel. A full structural elucidation of all synthesised compounds were carried out using amongst others 1D and 2D NMR spectroscopy and mass spectrometry. The data presented here will provide a basis for the identification of further molecules of this type. The hybrid molecules were then subjected to antibacterial bioassays against Gram -ve and Gram +ve bacterial strains. Unfortunately, only one compound, the 6-bromo-4'-fluoro derivative on the (E)-2-quinoline-2- yl)methylene-N-phenylhydrazinecarbothiamide framework showed any antibacterial activity. They were active against both Staphylococus aureus and methicillin resistant Staphylococcus aureus (MRSA) at 387 uM.