Discovery of Diaryl Ether Substituted Tetrahydrophthalazinones as TbrPDEB1 Inhibitors Following Structure-Based Virtual Screening

The Bis(indolylmethyl) ethers: Design, Prototypical Synthesis, and Scope Studies

The design, prototypical synthesis, isolation, and characterization of bis(indolylmethyl) ethers from corresponding indolylcarbinols is described. This approach involves very mild conditions and exhibits good scope for indolylcarbinols (both N-electron withdrawing group and N-electron donating group). Cross etherification between two electronically different indolylcarbinols is also demonstrated for the generation of unsymmetrical ethers. For the first time, the intermediacy of the bis(indolylmethyl) ethers for the formation of bis(indolyl)methanes from indolylcarbinols is proved experimentally and by 1H NMR analysis.

Targeting trypanosomes: how chemogenomics and artificial intelligence can guide drug discovery

Trypanosomatids are protozoan parasites that cause human and animal neglected diseases. Despite global efforts, effective treatments are still much needed. Phenotypic screens have provided several chemical leads for drug discovery, but the mechanism of action for many of these chemicals is currently unknown. Recently, chemogenomic screens assessing the susceptibility or resistance of parasites carrying genome-wide modifications started to define the mechanism of action of drugs at large scale. In this review, we discuss how genomics is being used for drug discovery in trypanosomatids, how integration of chemical and genomics data from these and other organisms has guided prioritisations of candidate therapeutic targets and additional chemical starting points, and how these data can fuel the expansion of drug discovery pipelines into the era of artificial intelligence.

3-nitroimidazo[1,2-b]pyridazine as a novel scaffold for antiparasitics with sub-nanomolar anti-Giardia lamblia activity

As there is a continuous need for novel anti-infectives, the present study aimed to fuse two modes of action into a novel 3-nitroimidazo[1,2-b]pyridazine scaffold to improve antiparasitic efficacy. For this purpose, we combined known structural elements of phosphodiesterase inhibitors, a target recently proposed for Trypanosoma brucei and Giardia lamblia, with a nitroimidazole scaffold to generate nitrosative stress. The compounds were evaluated in vitro against a panel of protozoal parasites, namely Giardia lamblia, Trypanosoma brucei, T. cruzi, Leishmania infantum and Plasmodium falciparum and for cytotoxicity on MRC-5 cells. Interestingly, selective sub-nanomolar activity was obtained against G. lamblia, and by testing several analogues with and without the nitro group, it was shown that the presence of a nitro group, but not PDE inhibition, is responsible for the low IC₅₀ values of these novel compounds. Adding the favourable drug-like properties (low molecular weight, cLogP (1.2–4.1) and low polar surface area), the key compounds from the 3-nitroimidazo[1,2-b]pyridazine series can be considered as valuable hits for further anti-giardiasis drug exploration and development.

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Analogues fusing a nitroimidazole moiety and a PDE inhibitor scaffold were prepared.

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These compounds were tested in vitro against a panel of protozoal parasites.

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Against Giardia lamblia, sub-nanomolar IC₅₀ values were determined.

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PDE inhibition provided no significant contribution to the anti-Giardia potency.

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High potency with drug-like properties warrants further study of this hit series.