Cu(I)Cl-promoted synthesis of novel N-alkylated isatin analogs with an extension toward isatin-4-aminoquinoline conjugates: in vitro analysis against Trichomonas vaginalis

Abstract

Trichomonas vaginalis, the causative agent of trichomonosis, is the most common non-viral sexually transmitted disease. Infection with this protozoan may have serious consequences, especially for women. Currently, 5-nitroimidazole drugs are the treatment of choice for trichomonosis, but the emergence of drug resistant isolates has limited the effectiveness of this therapy. In this context, a library of isatin-mannich adducts and 4-aminoquinoline-isatin mannich conjugates was synthesized following the Cu-promoted Mannich reaction and evaluated for their preliminary in vitro analysis against T. vaginalis at 50 μM. The preliminary evaluation data revealed that the introduction of 4-aminoquinoline ring enhanced the activity profiles with compounds viz. 6a and 6c exhibiting percentage growth inhibition of 92.13 and 100 %, respectively. Compounds with high levels of potency were further analyzed to determine their IC50 values as well as cytotoxicity profiles against mammalian cells. The most active compound in the synthesized conjugates displayed an IC50 value of 23 μM against cultured G3 strain in TYM Diamond’s media of T. vaginalis and was non-toxic to cultured mammalian HeLa cells at the same concentration. Synthesis of N-alkylated isatin analogs, 4-aminoquinoline isatin hybrids, in vitro evaluation against trichomoniasis and cytotoxicities against HeLa cells.