N1-{4-[(10S)-Dihydroartemisinin-10-oxyl]}phenylmethylene-N 2-(2-methylquinoline-4-yl)hydrazine derivatives as antiplasmodial falcipain-2 inhibitors
A series of N1-{4-[(10S)-dihydroartemisinin- 10-oxyl]}phenylmethylene-N2-(2-methylquinoline-4-yl) hydrazine derivatives 9a-9n possessing 4-quinolylhydrazone and artemisinin cores were herein synthesized and evaluated for their activities against cysteine protease falcipain- 2 of Plasmodium falciparum. The structures were clearly confirmed by elemental analysis, 1H NMR, and mass spectra. The pharmacological results indicated that all compounds showed excellent activity against recombinant falcipain-2 (IC50 = 0.15-2.28 μM). The best one of this series was compound 9d (IC50 = 0.15 μM). The molecular docking results showed that the compound 9d made close contact with the key active site of cysteine protease falcipain-2.
Microwave-assisted synthesis of 4-quinolylhydrazines followed by nickel boride reduction: a convenient approach to 4-aminoquinolines and derivatives
Nickel(II) chloride/sodium borohydride combination was employed for the reduction of 4-hydrazinoquinoline derivatives to the corresponding anilines. This reductive protocol was efficiently applied for the reductive cleavage of monosubstituted hydrazines. We described herein the microwave-assisted synthesis of 4-hydrazinoquinolines, which furnished a high yielding and rapid two-step procedure for the synthesis, under mild conditions, of 4-aminoquinolines as antimalarial precursors.