Synthesis and evaluation of 1-amino-6-halo-ß-carbolines as antimalarial and antiprion agents.

Malaria is one of the world's most devastating parasitic diseases, causing almost one million deaths each year. Growing resistance to classical antimalarial drugs, such as chloroquine, necessitates the discovery of new therapeutic agents for successful control of this global disease. Here, we report the synthesis of some 6-halo-ß-carbolines as analogues of the potent antimalarial natural product, manzamine A, retaining its heteroaromatic core whilst providing compounds with much improved synthetic accessibility. Two compounds displayed superior activity to chloroquine itself against a resistant Plasmodium falciparum strain, identifying them as promising leads for future development. Furthermore, in line with previous reports of similarities in antimalarial and antiprion effects of aminoaryl-based antimalarial agents, the 1-amino-ß-carboline libraries were also found to possess significant bioactivity against a prion-infected cell line.

2,4-diarylthiazole antiprion compounds as a novel structural class of antimalarial leads.

A significant intersection between antimalarial and antiprion activity is well established for certain compound classes, specifically for polycyclic antimalarial agents bearing basic nitrogen-containing sidechains (e.g., chloroquine, quinacrine, mefloquine). Screening a recently reported set of antiprion compounds with such sidechains showed these 2,4-diarylthiazole based structures also possess significant antimalarial activity. Of particular note, all but one of the compounds displayed activity against a chloroquine-resistant Plasmodium falciparum strain, identifying them as interesting leads for further development in this context. In addition, three new members of the series showed superior antiprion activity compared to the earlier-reported compounds.