Design, Synthesis, and In Vitro Antileishmanial and Antitumor Activities of New Tetrahydroquinolines

A novel series of tetrahydroquinolines containing acetohydrazide, oxopyrazole, oxothioxodihydropyrazole, and thioxotriazole have been synthesized. Antileishmanial, antitumor, and cytotoxicity activities of synthesized compounds were evaluated in vitro . Antileishmanial activity of the most synthesized compounds showed tremendous activity towards Leishmania major . Most of the test compounds exhibited significant level of tumor inhibition. The tetrahydropyrano[2,3‐ b ]quinolin‐2‐one 6 and 4‐oxo‐4 H ‐pyrazol‐3‐yloxytetrahydroquinoline‐3‐carbonitrile derivatives 18 showed 100% tumor inhibition comparable with standard drug vincristine (100% tumor inhibition). Tetrahydroquinolines under investigation showed cytotoxicity with LD 50 values in the range 0.56–3.01 μg/mL compared with standard drug MS‐222 with LD 50 value of 4.30 μg/mL. The presence of a pyrazole ring markedly improved the activity profiles of tetrahydroquinoline. All newly synthesized compounds were characterized by IR, 1 H NMR, and MS.