Efficient synthesis, structure elucidation, and anti-parasitic activities of novel quinolinyl β–enaminones

In the present study, a novel series of side chain-modified quinoline β-enaminones were synthesized in good-to-excellent yields. The structures of all the synthesized compounds have been established with the help of spectral and analytical data and also by X-ray crystallography. All the compounds were screened for their potential in vitro anti-malarial activity against chloroquine resistant strain K1 and chloroquine sensitive strain 3D7. The compounds were also evaluated for their in vitro microfilaricidal and adulticidal effect against B. malayi microfilariae and adult worms using ivermectin as positive control. The cytotoxicity of the compounds was checked against Vero cell line and all the compounds were found to be non-toxic. The compounds showed low antimalarial activities against both the plasmodial strains compared to the standard drug chloroquine. However, four of the evaluated compounds have shown significant in vitro adulticidal activity and their percentage inhibition were found to be 68, 55, 64, and 66, respectively. Two of these were selected for further preliminary in vivo activity studies.