4-Aryl Pyrrolidines as a Novel Class of Orally Efficacious Antimalarial Agents. Part 1: Evaluation of 4-Aryl- N-benzylpyrrolidine-3-carboxamides.

Identification of novel chemotypes with antimalarial efficacy is imperative to combat the rise of Plasmodium species resistant to current antimalarial drugs. We have used a hybrid target-phenotype approach to identify and evaluate novel chemotypes for malaria. In our search for drug-like aspartic protease inhibitors in publicly available phenotypic antimalarial databases, we identified GNF-Pf-4691, a 4-aryl- N-benzylpyrrolidine-3-carboxamide, as having a structure reminiscent of known inhibitors of aspartic proteases. Extensive profiling of the two terminal aryl rings revealed a structure-activity relationship in which relatively few substituents are tolerated at the benzylic position, but the 3-aryl position tolerates a range of hydrophobic groups and some heterocycles. Out of this effort, we identified (+)-54b (CWHM-1008) as a lead compound. 54b has EC50 values of 46 and 21 nM against drug-sensitive Plasmodium falciparum 3D7 and drug-resistant Dd2 strains, respectively. Furthermore, 54b has a long half-life in mice (4.4 h) and is orally efficacious in a mouse model of malaria (qd; ED99 ∼ 30 mg/kg/day). Thus, the 4-aryl- N-benzylpyrrolidine-3-carboxamide chemotype is a promising novel chemotype for malaria drug discovery.

Synthesis and Evaluation of Novel Erlotinib-NSAID Conjugates as More Comprehensive Anticancer Agents.

A series of novel anticancer agents were designed and synthesized based on coupling of different nonsteroidal anti-inflammatory drugs (NSAIDs) with the epidermal growth-factor receptor (EGFR) tyrosine kinase inhibitor, erlotinib. Both the antiproliferative and pharmacokinetic activity of the target compounds were evaluated using HCC827 and A431 tumor cell lines. Among the derivatives made, compounds 10a, 10c, and 21g showed superb potency, comparable to that of erlotinib. Furthermore, preliminary SAR analysis showed that when the NSAIDs were conjugated via linkage to C-6 OH versus linkage to C-7 OH of the quinazoline nucleus, superior anticancer activity was achieved. Finally, the in vitro pharmacokinetic profile of several conjugates demonstrated the desired dissociation kinetics as the coupled molecules were effectively hydrolyzed, releasing both erlotinib and the specific NSAID in a time-dependent manner. The conjugation strategy represents a unique and simplified approach toward combination therapy, particularly for the treatment of cancers where both EGFR overexpression and inflammation play a direct role in disease progression.