Synthesis, Cruzain Docking, and in vitro Studies of Aryl-4-Oxothiazolylhydrazones Against Trypanosoma cruzi

Research in recent years has demonstrated that the Trypanosoma cruzi cysteine protease cruzain (TCC) is a valid chemotherapeutic target. Herein we describe a small library of aryl‐4‐oxothiazolylhydrazones that have been tested in assays against T. cruzi cell cultures. The docking studies carried out suggest that these compounds are potential ligands for the TCC enzyme. The most promising compound of this series, N‐(4‐oxo‐5‐ethyl‐2′‐thiazolin‐2‐yl)‐N′‐phenylthio‐(Z)‐ethylidenehydrazone (6 f), was shown to be very active at non‐cytotoxic concentrations in in vitro assays with mammalian cells and has a potency comparable with reference drugs such as nifurtimox (Nfx) and benznidazole (Bdz). Aiming for a key target: Aryl‐4‐oxothiazolylhydrazones such as (R)‐6 f (in blue) are capable of inhibiting the growth of Trypanosoma cruzi cell cultures at non‐cytotoxic concentrations. Their role as potential inhibitors of the T. cruzi cysteine protease cruzain (TCC) is explored in relation to drugs in current use such as benznidazole (Bdz, in orange).