Design, Synthesis, and Biological Evaluation of 4,4'-Difluorobenzhydrol Carbamates as Selective M1 Antagonists.

Jonas Kilian,Wolfgang Holzer,Marlon Millard,Verena Maisetschläger,Dorka Fürtös,Thierry Langer,Marcus Hacker,Wolfgang Wadsak,Verena Pichler,Marius Ozenil

doi:10.3390/ph15020248

Abstract

Due to their important role in mediating a broad range of physiological functions, muscarinic acetylcholine receptors (mAChRs) have been a promising target for therapeutic and diagnostic applications alike; however, the list of truly subtype-selective ligands is scarce. Within this work, we have identified a series of twelve 4,4’-difluorobenzhydrol carbamates through a rigorous docking campaign leveraging commercially available amine databases. After synthesis, these compounds have been evaluated for their physico–chemical property profiles, including characteristics such as HPLC-logD, tPSA, logBB, and logPS. For all the synthesized carbamates, these characteristics indicate the potential for BBB permeation. In competitive radioligand binding experiments using Chinese hamster ovary cell membranes expressing the individual human mAChR subtype hM1-hM5, the most promising compound 2 displayed a high binding affinitiy towards hM1R (1.2 nM) while exhibiting modest-to-excellent selectivity versus the hM2-5R (4–189-fold). All 12 compounds were shown to act in an antagonistic fashion towards hM1R using a dose-dependent calcium mobilization assay. The structural eligibility for radiolabeling and their pharmacological and physico–chemical property profiles render compounds 2, 5, and 7 promising candidates for future position emission tomography (PET) tracer development.

Highlights

Introduction published maps and institutional affilMuscarinic acetylcholine receptors belong to the superfamily of G-proteincoupled receptors (GPCRs) which, upon activation by their endogenous neurotransmitter acetylcholine, elicit a multitude of peripheral and central physiological functions such as cognitive function, motor control, and cardiovascular function
We started our in silico (Figure 3) workflow to design and evaluate carbamate-bridged compounds based on 4-FBA by preparing a narrowly focused library of commercially available diamines, with the structural prerequisite of one amine moiety being an aliphatic tertiary N-methyl amine enclosed in a cyclic structure
We have demonstrated with the design of this hM1 preferring carbamate series that subtle structural changes can have profound effects on binding affinities and good subtype selectivity is not an unrealistic objective even in the case of orthosteric muscarinic acetylcholine receptors (mAChRs) ligands

Summary

Introduction

Introduction published maps and institutional affilMuscarinic acetylcholine receptors (mAChRs) belong to the superfamily of G-proteincoupled receptors (GPCRs) which, upon activation by their endogenous neurotransmitter acetylcholine, elicit a multitude of peripheral and central physiological functions such as cognitive function, motor control, and cardiovascular function. There are five subtypes of mAChRs (M1 –M5 ), all of which are expressed in varying degrees throughout the human body [1]. Their abundant expression in the central nervous system (CNS), in particular, led to them being the therapeutic target of numerous research efforts targeting pathologies such as Alzheimer’s disease, Parkinson’s disease, and schizophrenia [2,3,4,5]; these efforts have not been the most fruitful—attributable to the highly conserved orthosteric binding site shared among M1 –M5 , posing a severe constraint on subtype-selective drug development [2]. Is the design of ligands preferably targeting, for example, the M1 or M4 receptors, known targets for neurological diseases [6,7], a difficult task to achieve, but iations.

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