Synthesis, structural studies and antituberculosis evaluation of new hydrazone derivatives of quinoline and their Zn(II) complexes
Abstract The quinoline hydrazone ligands were synthesized through multi step reactions. The 2 hydroxy 3 formylquinoline derivatives 1a 1c) were prepared from acetanilide derivatives as starting materials using Vilsmeier Haack reaction. Then the condensation of 2 hydroxy 3 formylquinoline derivatives with hydrazide derivatives 2a 2c) yielded quinoline hydrazone ligands 3a 3i) The synthesis of a new series of Zn(II) complexes carried out by refluxing with these quinoline hydrazone ligands 3a 3i) is reported. The molecular structures of the ligands 3a 3i) and the Zn complexes were characterized by elemental analysis and spectral studies like FT IR, 1 H and 13 C NMR, MS, UV Visible and fluorescence. The preliminary results of antituberculosis study showed that most of the Zn(II) complexes 4a 4i demonstrated very good antituberculosis activity while the ligands 3a 3i showed moderate activity. Among the tested compounds 4e and 4g were found to be most active with minimum inhibitory concentration (MIC) of 8.00 mM and 7.42 mM respectively against Mycobacterium tuberculosis (H37 RV strain) ATCC No 27294 which is comparable to "first and second line" drugs used to treat tuberculosis.