Synthesis, characterization and trypanocidal activity of some aromatic thiosemicarbazones and their 1,3,4-thiadiazolines derivatives

The thiosemicarbazones of six aromatic ketones were synthesized as well as their 1,3,4-thiadiazolines derivatives obtained by cyclization under acetylating condition with yields going from 40 to 90%. The products purity was confirmed by mass spectrometry coupled with high-performance liquid chromatography (LC/MS) and there were characterized using spectrometry IR, NMR 1H and 13C (nuclear magnetic resonance). These compounds were then tested in vitro on Trypanosoma brucei brucei according to the “LILIT, Alamar Blue” method for a comparison of their trypanocidal activity. Thus, all thiosemicarbazones appeared much more active than their corresponding 1,3,4-thiadiazolines. Thiosemicarbazone 6a (IC50 = 9.62 µM) was the most active of all thiosemicarbazones tested and it is the same for its thiadiazoline 6b (IC50 = 49.03 µM) among 1,3,4-thiadiazolines.