Direct, Late-Stage Mono-N-arylation of Pentamidine: Method Development, Mechanistic Insight, and Expedient Access to Novel Antiparastitics against Diamidine-Resistant Parasites

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Robertson J, Ungogo MA, Aldfer MM, Lemgruber L, McWhinnie FS, Bode BE, Jones KL, Watson AJB, de Koning HP, Burley GA.

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ChemMedChem. 2021 Aug 6. doi: 10.1002/cmdc.202100509. Online ahead of print.

Abstract

A selective mono-N-arylation strategy of amidines under Chan-Lam conditions is described. During the reaction optimization phase, the isolation of a mononuclear Cu(II) complex provided unique mechanistic insight into the operation of Chan-Lam mono-N-arylation. The scope of the process is demonstrated, and then applied to access the first mono-N-arylated analogues of pentamidine. Sub-micromolar activity against kinetoplastid parasites was observed for several analogues with no cross-resistance in pentamidine and diminazene-resistant trypanosome strains and against Leishmania mexicana. A fluorescent mono-N-arylated pentamidine analogue revealed rapid cellular uptake, accumulating in parasite nuclei and the kinetoplasts. The DNA binding capability of the mono-N-arylated pentamidine series was confirmed by UV-melt measurements using AT-rich DNA. This work highlights the potential to use Chan-Lam mono-N-arylation to develop therapeutic leads against diamidine-resistant trypanosomiasis and leishmaniasis. CI – © 2021 The Authors. ChemMedChem published by Wiley-VCH GmbH.

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Link/DOI: 10.1002/cmdc.202100509