Modification of agonist binding moiety in hybrid derivative 5/7-{[2-(4-aryl-piperazin-1-yl)-ethyl]-propyl-amino}-5,6,7,8-tetrahydro-naphthalen-1-ol/-2-amino versions: impact on functional activity and selectivity for dopamine D2/D3 receptors

Synthesis and structure-activity relationships for a new class of tetrahydronaphthalene amide inhibitors of Mycobacterium tuberculosis

Drug resistant tuberculsosis (TB) is global health crisis that demands novel treatment strategies. Bacterial ATP synthase inhibitors such as bedaquiline and next-generation analogues (such as TBAJ-876) have shown promising efficacy in patient populations and preclinical studies, respectively, suggesting that selective targeting of this enzyme presents a validated therapeutic strategy for the treatment of TB. In this work, we report tetrahydronaphthalene amides (THNAs) as a new class of ATP synthase inhibitors that are effective in preventing the growth of Mycobacterium tuberculosis (M.tb) in culture. Design, synthesis and comprehensive structure-activity relationship studies for approximately 80 THNA analogues are described, with a small selection of compounds exhibiting potent (in some cases MIC₉₀ <1 μg/mL) in vitro M.tb growth inhibition taken forward to pharmacokinetic and off-target profiling studies. Ultimately, we show that some of these THNAs possess reduced lipophilic properties, decreased hERG liability, faster mouse/human liver microsomal clearance rates and shorter plasma half-lives compared with bedaquiline, potentially addressing of the main concerns of persistence and phospholipidosis associated with bedaquiline.

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Tetrahydronaphthalene amides are novel inhibitors of M.tb in culture.

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Selective and potent inhibitors of the mycobacterial ATP synthase.

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Improved hERG liability, clearance and half-life compared to bedaquiline.

Design, Synthesis, and Biological Evaluation of Phenol Bioisosteric Analogues of 3-Hydroxymorphinan

The neuroprotective agent 3-hydroxymorphinan (3-HM) is a well-documented and highly safe therapeutic intervention for the inflammatory-related effects of Parkinson’s disease (PD). However, the bioavailability of 3-HM is very low due to the rapid first-pass metabolism of the phenolic moiety. In the present study, we sought to improve the metabolic stability and overall pharmacokinetic profile of 3-HM. Based on an iterative design process that a suitably arranged heterocycle with an NH group would serve as the metabolically stable isostere of the phenolic group, we designed and synthesized two analogues of 3-HM. Benzimidazolone compound 8 (imidazolone-morphinan) was comparable in activity to 3-HM against lipopolysaccharide (LPS)-induced inflammatory responses in microglial BV2 cells and in vivo animal experiments (MPTP-induced PD mouse model). Moreover, the in vitro study showed that imidazolone-morphinan was non-toxic to microglia, indicating its high safety. Considering the favourable and unique preclinical profiles, compound 8 was nominated as a candidate for further clinical development.

Synthesis and Cytotoxic Evaluation of Pyrrole Hetarylazoles Containing Benzimidazole/Pyrazolone/1,3,4-Oxadiazole Motifs

Azomethine linked pyrrole bishetarylazoles containing benzimidazole/pyrazolone/1,3,4-oxadiazole were synthesized in satisfactory yields. Their structures were confirmed by IR, 1H-NMR, 13C-NMR and elemental analysis. Evaluation for the cytotoxic activities In vitro against a panel of breast cancer cell lines (MDA-AB-231, BT-474 and Ishikawa cells) revealed that the pyrrole-benzimidazole hybrids are more potent than the pyrazolone and 1,3,4-oxadiazole hybrids in all cell lines. Compound (9) displayed promising cytotoxicity against BT-474 cell line with IC50 values, 7.7 µM.

Dopamine D3 receptor agonists as pharmacological tools

Dysregulation of the dopaminergic innervation in the central nervous system plays a key role in different neurological disorders like Parkinson´s disease, restless legs syndrome, schizophrenia etc. Although dopamine D3 receptors have been recognized as an important target in these diseases, their full pharmacological properties need further investigations. With focus on dopamine D3 receptor full agonists, this review has divided the ergoline and non-ergoline ligands in dissimilar chemical subclasses describing their pharmacodynamic properties on different related receptors, on species differences and their functional properties on different signaling mechanism. This is combined with a short description of structure-activity relationships for each class. Therefore, this overview should support the rational choice for the optimal compound selection based on affinity, selectivity and efficacy data in biochemical and pharmacological studies.

Multicomponent Synthesis and Biological Evaluation of a Piperazine-Based Dopamine Receptor Ligand Library

A series of 1,4-disubstituted piperazine-based compounds were designed, synthesized, and evaluated as dopamine D2/D3 receptor ligands. The synthesis relies on the key multicomponent split-Ugi reaction, assessing its great potential in generating chemical diversity around the piperazine core. With the aim of evaluating the effect of such diversity on the dopamine receptor affinity, a small library of compounds was prepared, applying post-Ugi transformations. Ligand stimulated binding assays indicated that some compounds show a significant affinity, with K i values up to 53 nM for the D2 receptor. Molecular docking studies with the D2 and D3 receptor homology models were also performed on selected compounds. They highlighted key interactions at the indole head and at the piperazine moiety, which resulted in good agreement with the known pharmacophore models, thus helping to explain the observed structure-activity relationship data. Molecular insights from this study could enable a rational improvement of the split-Ugi primary scaffold, toward more selective ligands.