Old Dogs with New Tricks: Antiparasitic Potential of Structurally Diverse 5-Nitrofuran and 5-Nitrothiophene Imines and Acyl Hydrazones

Miscellaneous imines and acyl hydrazones were prepared from 5-nitrofuraldehyde and 5-nitrothiophene-2-carboxaldehyde. Their activities against Toxoplasma gondii and Leishmania major parasites were evaluated. Promising antiparasitic effects and selectivities were observed for certain acyl hydrazones and imines. Cobalt(II) and copper(II) complexes conserved the high anti- Toxoplasma activities of 3-hydroxy-2-naphthoic carboxyl hydrazone ( 2a ). In addition, sound activities against L. major promastigotes were observed for various analogs of 2a ( 2b and 2i ) and pyrid-2-ylpyrazole-based imines ( 3g and 3h ). Relatively low toxicities to kidney cells and macrophages indicate promising selectivity profiles for these compounds.