Substituted carbazoles: a new class of anthelmintic agent

A series of novel carbazoles were synthesized based on structural modifications to lead carbazole 1 (EC100≤2.5M against Haemonchus contortus in vitro), which was revealed in a small molecule screening program as a potentially promising platform for the development of new anthelmintic drugs. Subsequently, analogues 19, 21, 41, 42 (EC100≤ 1.25M, all), and 39 (EC100≤0.625M) were demonstrated to exhibit enhanced in vitro anthelmintic activity over the lead structure, with compound 39 also being shown to be active in vivo against Heligmosomoides polygyrus.