Synthesis and NMR characterization of acetyl-pyrazine methyl thiosemicarbazone and acetyl-pyrazine ethyl-thiosemicarbazone ligands: Pd(II) and Pt(II) complexes

Abstract

Through experimentation, it has been discovered that thiosemicarbazone ligands and their metal complexes can be used for medicinal uses by inhibiting human topoisomerase IIα, as an alternate treatment for chemotherapy. In this research, acetyl-pyrazine methyl thiosemicarbazone [APZ-MTCS] and acetyl-pyrazine ethyl thiosemicarbazone [APZ-ETSC] ligands were synthesized and purified. After the synthesis and purification of [APZ-MTCS] and [APZ-ETSC] ligands, the 1H NMR and 13C NMR spectra were obtained using a new 500 MHz NMR spectrometer. Structural information was obtained by running 2D HSQC (heteronuclear single quantum coherence) 1H-13C NMR and HSQC 1H-15NNMR experiments, which provide evidence of our predicted structures. After the analysis was complete, we reacted the ligands with Pd(II) and two synthesis routes of Pt(II), using dichlorobis (benzonitrile) platinum(II) and potassium tetrachloroplatinate(II), to form their metal complexes. Similar NMR experiments were performed on the Pd(II) and Pt(II) complexes. A topoisomerase assay ran with an inhibition concentration between 2-6micro molar on the metal complexes. This poster will present the synthesis of [APZ-MTSC] and [APZ-ETSC] and the reactions with their metal complexes, the NMR characterization, and discussion of the topoisomerase assay results.