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Buskes MJ, Harvey KL, Richards BJ, Kalhor R, Christoff RM, Gardhi CK, Littler DR, Cope ED, Prinz B, Weiss GE, O'Brien NJ, Crabb BS, Deady LW, Gilson PR, Abbott BM. Antimalarial activity of novel 4-cyano-3-methylisoquinoline inhibitors against Plasmodium falciparum: design, synthesis and biological evaluation. Org Biomol Chem 2018; 14:4617-39. [PMID: 27105169 DOI: 10.1039/c5ob02517f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Central to malaria pathogenesis is the invasion of human red blood cells by Plasmodium falciparum parasites. Following each cycle of intracellular development and replication, parasites activate a cellular program to egress from their current host cell and invade a new one. The orchestration of this process critically relies upon numerous organised phospho-signaling cascades, which are mediated by a number of central kinases. Parasite kinases are emerging as novel antimalarial targets as they have diverged sufficiently from their mammalian counterparts to allow selectable therapeutic action. Parasite protein kinase A (PfPKA) is highly expressed late in the cell cycle of the parasite blood stage and has been shown to phosphorylate a critical invasion protein, Apical Membrane Antigen 1. This enzyme could therefore be a valuable drug target so we have repurposed a substituted 4-cyano-3-methylisoquinoline that has been shown to inhibit rat PKA with the goal of targeting PfPKA. We synthesised a novel series of compounds and, although many potently inhibit the growth of chloroquine sensitive and resistant strains of P. falciparum, they were found to have minimal activity against PfPKA, indicating that they likely have another target important to parasite cytokinesis and invasion.
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Affiliation(s)
- Melissa J Buskes
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia.
| | - Katherine L Harvey
- Centre for Biomedical Research, Burnet Institute, Melbourne, Victoria 3004, Australia and Department of Microbiology and Immunology, Peter Doherty Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Benjamin J Richards
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia.
| | - Robabeh Kalhor
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia.
| | - Rebecca M Christoff
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia.
| | - Chamodi K Gardhi
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia.
| | | | - Elliott D Cope
- Centre for Biomedical Research, Burnet Institute, Melbourne, Victoria 3004, Australia
| | - Boris Prinz
- Centre for Biomedical Research, Burnet Institute, Melbourne, Victoria 3004, Australia
| | - Greta E Weiss
- Centre for Biomedical Research, Burnet Institute, Melbourne, Victoria 3004, Australia
| | - Nathan J O'Brien
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia.
| | - Brendan S Crabb
- Centre for Biomedical Research, Burnet Institute, Melbourne, Victoria 3004, Australia and Department of Microbiology and Immunology, Peter Doherty Institute, University of Melbourne, Melbourne, Victoria 3010, Australia and Monash University, Melbourne, Victoria 3800, Australia
| | - Leslie W Deady
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia.
| | - Paul R Gilson
- Centre for Biomedical Research, Burnet Institute, Melbourne, Victoria 3004, Australia and Monash University, Melbourne, Victoria 3800, Australia
| | - Belinda M Abbott
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia.
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Abstract
[reaction: see text] A novel one-pot synthesis of N-difluoromethyl-2-pyridones is described. N-(Pyridin-2-yl)acetamide derivatives were excellent precursors for the preparation of N-difluoromethyl-2-pyridone derivatives. Difluoromethylation of 2-acetaminopyridine derivatives was achieved with sodium chlorodifluoroacetate as a difluorocarbene source in the presence of a catalytic amount of 18-crown-6. Subsequent in situ hydrolysis of resultant 1,2-dihydro-2-acetimino-1-difluoromethylpyridines proceeded under mild acidic conditions to afford the corresponding N-difluoromethyl-2-pyridones in moderate to good yields.
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Affiliation(s)
- Makoto Ando
- Tsukuba Research Institute, Banyu Pharmaceutical Company, Ltd., Okubo 3, Tsukuba 300-2611, Japan.
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