Methylene amine substituted arylindenopyrimidines as potent adenosine A2A/A1 antagonists

Indane-1,3-Dione: From Synthetic Strategies to Applications

Indane-1,3-dione is a versatile building block used in numerous applications ranging from biosensing, bioactivity, bioimaging to electronics or photopolymerization. In this review, an overview of the different chemical reactions enabling access to this scaffold but also to the most common derivatives of indane-1,3-dione are presented. Parallel to this, the different applications in which indane-1,3-dione-based structures have been used are also presented, evidencing the versatility of this structure.

Characterization of the trigeminovascular actions of several adenosine A2A receptor antagonists in an in vivo rat model of migraine

BACKGROUND

Migraine is considered a neurovascular disorder, but its pathophysiological mechanisms are not yet fully understood. Adenosine has been shown to increase in plasma during migraine attacks and to induce vasodilation in several blood vessels; however, it remains unknown whether adenosine can interact with the trigeminovascular system. Moreover, caffeine, a non-selective adenosine receptor antagonist, is included in many over the counter anti-headache/migraine treatments.

METHODS

This study used the rat closed cranial window method to investigate in vivo the effects of the adenosine A_2A receptor antagonists with varying selectivity over A₁ receptors; JNJ-39928122, JNJ-40529749, JNJ-41942914, JNJ-40064440 or JNJ-41501798 (0.3-10 mg/kg) on the vasodilation of the middle meningeal artery produced by either CGS21680 (an adenosine A_2A receptor agonist) or endogenous CGRP (released by periarterial electrical stimulation).

RESULTS

Regarding the dural meningeal vasodilation produced neurogenically or pharmacologically, all JNJ antagonists: (i) did not affect neurogenic vasodilation but (ii) blocked the vasodilation produced by CGS21680, with a blocking potency directly related to their additional affinity for the adenosine A₁ receptor.

CONCLUSIONS

These results suggest that vascular adenosine A_2A (and, to a certain extent, also A₁) receptors mediate the CGS21680-induced meningeal vasodilation. These receptors do not appear to modulate prejunctionally the sensory release of CGRP. Prevention of meningeal arterial dilation might be predictive for anti-migraine drugs, and since none of these JNJ antagonists modified per se blood pressure, selective A_2A receptor antagonism may offer a novel approach to antimigraine therapy which remains to be investigated in clinical trials.

Current Nondopaminergic Therapeutic Options for Motor Symptoms of Parkinson's Disease

Objective:

The aim of this study was to summarize recent studies on nondopaminergic options for the treatment of motor symptoms in Parkinson's disease (PD).

Data Sources:

Papers in English published in PubMed, Cochrane, and Ovid Nursing databases between January 1988 and November 2016 were searched using the following keywords: PD, nondopaminergic therapy, adenosine, glutamatergic, adrenergic, serotoninergic, histaminic, and iron chelator. We also reviewed the ongoing clinical trials in the website of clinicaltrials.gov.

Study Selection:

Articles related to the nondopaminergic treatment of motor symptoms in PD were selected for this review.

Results:

PD is conventionally treated with dopamine replacement strategies, which are effective in the early stages of PD. Long-term use of levodopa could result in motor complications. Recent studies revealed that nondopaminergic systems such as adenosine, glutamatergic, adrenergic, serotoninergic, histaminic, and iron chelator pathways could include potential therapeutic targets for motor symptoms, including motor fluctuations, levodopa-induced dyskinesia, and gait disorders. Some nondopaminergic drugs, such as istradefylline and amantadine, are currently used clinically, while most such drugs are in preclinical testing stages. Transitioning of these agents into clinically beneficial strategies requires reliable evaluation since several agents have failed to show consistent results despite positive findings at the preclinical level.

Conclusions:

Targeting nondopaminergic transmission could improve some motor symptoms in PD, especially the discomfort of dyskinesia. Although nondopaminergic treatments show great potential in PD treatment as an adjunct therapy to levodopa, further investigation is required to ensure their success.

Carbamate substituted 2-amino-4,6-diphenylpyrimidines as adenosine receptor antagonists

A novel series of carbamate substituted 2-amino-4,6-diphenylpyrimidines was evaluated as potential dual adenosine A1 and A2A receptor antagonists. The majority of the synthesised compounds exhibited promising dual affinities, with A1Ki values ranging from 0.175 to 10.7 nM and A2AKi values ranging from 1.58 to 451 nM. The in vivo activity illustrated for 3-(2-amino-6-phenylpyrimidin-4-yl)phenyl morpholine-4-carboxylate (4c) is indicative of the potential of these compounds as therapeutic agents in the treatment of Parkinson's disease, although physicochemical properties may require optimisation.

2-Aminopyrimidines as dual adenosine A1/A2A antagonists

In this study thirteen 2-aminopyrimidine derivatives were synthesised and screened as potential antagonists of adenosine A1 and A2A receptors in order to further investigate the structure activity relationships of this class of compounds. 4-(5-Methylfuran-2-yl)-6-[3-(piperidine-1-carbonyl)phenyl]pyrimidin-2-amine (8m) was identified as a compound with high affinities for both receptors, with an A2AKi value of 6.34 nM and an A1Ki value of 9.54 nM. The effect of selected compounds on the viability of cultured cells was assessed and preliminary results indicate low cytotoxicity. In vivo efficacy at A2A receptors was illustrated for compounds 8k and 8m since these compounds attenuated haloperidol-induced catalepsy in rats. A molecular docking study revealed that the interactions between the synthesised compounds and the adenosine A2A binding site most likely involve Phe168 and Asn253, interactions which are similar for structurally related adenosine A2A receptor antagonists.

History and perspectives of A2A adenosine receptor antagonists as potential therapeutic agents

Growing evidence emphasizes that the purine nucleoside adenosine plays an active role as a local regulator in different pathologies. Adenosine is a ubiquitous nucleoside involved in various physiological and pathological functions by stimulating A1 , A2A , A2B , and A3 adenosine receptors (ARs). At the present time, the role of A2A ARs is well known in physiological conditions and in a variety of pathologies, including inflammatory tissue damage and neurodegenerative disorders. In particular, the use of selective A2A antagonists has been reported to be potentially useful in the treatment of Parkinson's disease (PD). In this review, A2A AR signal transduction pathways, together with an analysis of the structure-activity relationships of A2A antagonists, and their corresponding pharmacological roles and therapeutic potential have been presented. The initial results from an emerging polypharmacological approach are also analyzed. This approach is based on the optimization of the affinity and/or functional activity of the examined compounds toward multiple targets, such as A1 /A2A ARs and monoamine oxidase-B (MAO-B), both closely implicated in the pathogenesis of PD.

Adenosine A1 modulators: a patent update (2008 to present)

INTRODUCTION

In 2008, we published our review titled 'Therapeutic potential of A1 adenosine receptor ligands - a survey of recent patent literature' that reported the compounds active on A1 adenosine receptors (ARs) and the applications of A1 AR ligands patented in the period 2005 - 2008.

AREAS COVERED

This article is a discussion of the patents about the same subjects, issued in the period 2008 to present. It is organized similarly to the first one, with a section about new compounds, subdivided on the basis of their functional activity (agonists, antagonists and allosteric modulators) and a section regarding new therapeutic applications.

EXPERT OPINION

The main novelty is represented by the patenting of A1 AR ligands with dual selectivity which may show, in some conditions, better efficacy and fewer side effects. Moreover, while the way to arrive into the market appears full of obstacles for selective A1 ligands that need systemic administration for long-term therapy, better chances are foreseen in applications requiring topical administration.

Design and characterization of optimized adenosine A₂A/A₁ receptor antagonists for the treatment of Parkinson's disease

The design and characterization of two, dual adenosine A(2A)/A(1) receptor antagonists in several animal models of Parkinson's disease is described. Compound 1 was previously reported as a potential treatment for Parkinson's disease. Further characterization of 1 revealed that it was metabolized to reactive intermediates that caused the genotoxicity of 1 in the Ames and mouse lymphoma L51784 assays. The identification of the metabolites enabled the preparation of two optimized compounds 13 and 14 that were devoid of the metabolic liabilities associated with 1. Compounds 13 and 14 are potent dual A(2A)/A(1) receptor antagonists that have excellent activity, after oral administration, across a number of animal models of Parkinson's disease including mouse and rat models of haloperidol-induced catalepsy, mouse and rat models of reserpine-induced akinesia, and the rat 6-hydroxydopamine (6-OHDA) lesion model of drug-induced rotation.

Adenosine A(2A) Receptor Antagonists and Parkinson's Disease

This Review summarizes and updates the work on adenosine A(2A) receptor antagonists for Parkinson's disease from 2006 to the present. There have been numerous publications, patent applications, and press releases within this time frame that highlight new medicinal chemistry approaches to this attractive and promising target to treat Parkinson's disease. The Review is broken down by scaffold type and will discuss the efforts to optimize particular scaffolds for activity, pharmacokinetics, and other drug discovery parameters. The majority of approaches focus on preparing selective A(2A) antagonists, but a few approaches to dual A(2A)/A(1) antagonists will also be highlighted. The in vivo profiles of compounds will be highlighted and discussed to compare activities across different chemical series. A clinical report and update will be given on compounds that have entered clinical trials.

Optimization of arylindenopyrimidines as potent adenosine A(2A)/A(1) antagonists

Two reactive metabolites were identified in vivo for the dual A(2A)/A(1) receptor antagonist 1. Two strategies were implemented to successfully mitigate the metabolic liabilities associated with 1. Optimization of the arylindenopyrimidines led to a number of amide, ether, and amino analogs having comparable in vitro and in vivo activity.