We have described 5-(4-propoxycinnamoylamino)-2-(4-tolylacetylamino)benzophenone 6e as a novel lead for antimalarial agents. Anti-malarial activity of these 5-(4-propoxycinnamoylamino)benzophenones proved to be quite sensitive against variations of the acyl substituent at the 2-amino group. Best activity was obtained with phenylacetic acid moieties carrying small substituents in the para-position. From the para-substituents evaluated, the trifluoromethyl group yielded the most active compound (6j) in this series (IC50 = 120 nM). Deviations from the phenylacetic acid substructure, shifting the substituent into the ortho-position or bulkier para-substituents resulted in a significant reduction in anti-malarial activity. (C) 2002 Elsevier Science Ltd. All rights reserved.
Structure–Activity relationships of novel anti-Malarial agents: Part 5. N-(4-acylamino-3-benzoylphenyl)-[5-(4-nitrophenyl)-2-furyl]acrylic acid amides
We have developed the [5-(4-nitrophenyl)-2-furyl]acrylic acid substituted benzophenone 4g as a novel lead for antimalarial agents. Here, we demonstrated that the acyl residue at the 2-amino group of the benzophenone core structure has to be a phenylacetic acid substructure substituted in its para-position with methyl or other substituents of similar size. The triauoromethyl substituted derivative displayed an IC50 of 47 nM against the multi-drug resistant Plasmodium falciparum strain Dd2. (C) 2002 Elsevier Science Ltd. All rights reserved.