Novel 5-(nitrothiophene-2-yl)-1,3,4-Thiadiazole Derivatives: Synthesis and Antileishmanial Activity against promastigote stage of Leishmania major

In this study, a series of novel compounds based on 5-(5-nitrothiophene-2-yl)-1,3,4-thiadiazole possessing (het) aryl thio pendant at C-2 position of thiadiazole ring is developed and evaluated as antileishmanial agents using MTT colorimetric assay. 10 New compounds containing aryl and heteroaryl derivatives, started from thiophene-2-carbaldehyde in five steps, were synthesized in good to excellent yields and characterized by (1)H-NMR, (13)C-NMR, and IR spectroscopy. Through the compounds 6a-j, methylimidazole containing derivative 6e was recognized as the most active compound against L. major promastigotes exhibiting IC(50 )values of 11.2µg/mL and 7.1µg/mL after 24 and 48 h, respectively. This compound is > 4 fold more effective than Glucantime as a standard drug (IC(50 )= 50 µg/mL after 24 h and 25 µg/mL after 48 h).