Synthesis and Structure–Activity Relationship of Dual-Stage Antimalarial Pyrazolo[3,4-<i>b</i>]pyridines
Scott Eagon, Jared T. Hammill, Martina Sigal, Kevin J. Ahn, Julia E. Tryhorn, Grant Koch, Briana G. Belanger, Cory A. Chaplan, Lauren Loop, Anna S. Kashtanova, Kenya Yniguez, Horacio Lazaro, Steven Wilkinson, Amy L. Rice, Mofolusho O. Falade, Rei Takahashi, Katie Kim, Ashley Cheung, Céline DiBernardo, Joshua J. Kimball, Elizabeth A. Winzeler, Korina Eribez, Nimisha Mittal, Francisco‐Javier Gamo, Benigno Crespo, Alisje Churchyard, Irene García-Barbazán, Jake Baum, Marc O. Anderson, Benoı̂t Laleu, R. Kiplin Guy
Abstract
Malaria remains one of the most deadly infectious diseases, causing hundreds of thousands of deaths each year, primarily in young children and pregnant mothers. Here, we report the discovery and derivatization of a series of pyrazolo[3,4-b]pyridines targeting Plasmodium falciparum, the deadliest species of the malaria parasite. Hit compounds in this series display sub-micromolar in vitro activity against the intraerythrocytic stage of the parasite as well as little to no toxicity against the human fibroblast BJ and liver HepG2 cell lines. In addition, our hit compounds show good activity against the liver stage of the parasite but little activity against the gametocyte stage. Parasitological profiles, including rate of killing, docking, and molecular dynamics studies, suggest that our compounds may target the Qo binding site of cytochrome bc1.