The discovery and preclinical characterization of 6-chloro- N -(2-(4,4-difluoropiperidin-1-yl)-2-(2-(trifluoromethyl)pyrimidin-5-yl)ethyl)quinoline-5-carboxamide based P2X7 antagonists

Recommended tool compounds and drugs for blocking P2X and P2Y receptors

This review article presents a collection of tool compounds that selectively block and are recommended for studying P2Y and P2X receptor subtypes, investigating their roles in physiology and validating them as future drug targets. Moreover, drug candidates and approved drugs for P2 receptors will be discussed.

The purinergic P2X7 receptor as a potential drug target to combat neuroinflammation in neurodegenerative diseases

Neurodegenerative diseases (NDDs) represent a huge social burden, particularly in Alzheimer's disease (AD) in which all proposed treatments investigated in murine models have failed during clinical trials (CTs). Thus, novel therapeutic strategies remain crucial. Neuroinflammation is a common pathogenic feature of NDDs. As purinergic P2X7 receptors (P2X7Rs) are gatekeepers of inflammation, they could be developed as drug targets for NDDs. Herein, we review this challenging hypothesis and comment on the numerous studies that have investigated P2X7Rs, emphasizing their molecular structure and functions, as well as their role in inflammation. Then, we elaborate on research undertaken in the field of medicinal chemistry to determine potential P2X7R antagonists. Subsequently, we review the state of neuroinflammation and P2X7R expression in the brain, in animal models and patients suffering from AD, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, multiple sclerosis, and retinal degeneration. Next, we summarize the in vivo studies testing the hypothesis that by mitigating neuroinflammation, P2X7R blockers afford neuroprotection, increasing neuroplasticity and neuronal repair in animal models of NDDs. Finally, we reviewed previous and ongoing CTs investigating compounds directed toward targets associated with NDDs; we propose that CTs with P2X7R antagonists should be initiated. Despite the high expectations for putative P2X7Rs antagonists in various central nervous system diseases, the field is moving forward at a relatively slow pace, presumably due to the complexity of P2X7Rs. A better pharmacological approach to combat NDDs would be a dual strategy, combining P2X7R antagonism with drugs targeting a selective pathway in a given NDD.

Rhodium(III)-Catalyzed Oxidative Annulation of 4-Aminoquinolines and Acrylate through Two Consecutive C(sp2)-H Activations

The C-H annulation of the five-position of quinolines and acrylates to afford heterocycles is an active field of research in organic synthesis. Herein the annulation of 4-aminoquinolines with acrylates through two consecutive C-H activations catalyzed by Rh(III) is described. The reaction proceeds with high atom efficiency under mild reaction conditions, and this protocol will provide appealing strategies for the synthesis of fused quinoline heterocycles.

P2X7 receptor antagonists for the treatment of systemic inflammatory disorders

P2X7 has continued to be a target of immense interest since it is implicated in several peripheral and central nervous system disorders that result from inflammation. This review primarily describes new P2X7 receptor antagonists that have been investigated and disclosed in patent applications or primary literature since 2015. While a crystal structure of the receptor to aid in the design of novel chemical structures remains elusive, many of the chemotypes that have been disclosed contain similarities, with an amide motif present in all series that have been explored to date. Several of the recent antagonists described are brain penetrant, and two compounds are currently in clinical trials for CNS indications. Additionally, brain penetrant PET ligands have been developed that aid in measuring target engagement and these ligands can potentially be used as biomarkers.

Synthesis and SAR development of quinoline analogs as novel P2X7 receptor antagonists

The P2X7 receptor (P2X7R) plays an important role in diverse conditions associated with tissue damage and inflammation, suggesting that the human P2X7R (hP2X7R) is an attractive therapeutic target. In the present study, the synthesis and structure-activity relationship (SAR) of a novel series of quinoline derivatives as P2X7R antagonists are described herein. These compounds exhibited mechanistic activity (YO PRO) in an engineered HEK293 expressing hP2X7R as well as a functional response (IL-1β) in human THP-1 (hTHP-1) cellular assays. Compound 19 was identified as the most promising compound in this series with excellent cellular potency, low liver microsomal clearance, good permeability and low efflux ratio. In addition, this compound also displayed good pharmacokinetic properties and acceptable brain permeability (K_p,uu of 0.37).