Chemical lead optimization of a pan Gq mAChR M1, M3, M5 positive allosteric modulator (PAM) lead. Part II: development of a potent and highly selective M1 PAM.

This Letter describes a chemical lead optimization campaign directed at VU0119498, a pan G(q) mAChR M(1), M(3), M(5) positive allosteric modulator (PAM) with the goal of developing a selective M(1) PAM. An iterative library synthesis approach delivered a potent (M(1) EC(50)=830 nM) and highly selective M(1) PAM (>30 microM vs M(2)-M(5)).

Chemical lead optimization of a pan G(q) mAChR M(1), M(3), M(5) positive allosteric modulator (PAM) lead. Part I: Development of the first highly selective M(5) PAM.

This Letter describes a chemical lead optimization campaign directed at VU0238429, the first M(5)-preferring positive allosteric modulator (PAM), discovered through analog work around VU0119498, a pan G(q) mAChR M(1), M(3), M(5) PAM. An iterative library synthesis approach delivered the first selective M(5) PAM (no activity at M(1)-M(4) @ 30microM), and an important tool compound to study the role of M(5) in the CNS.

Synthesis and SAR of analogues of the M1 allosteric agonist TBPB. Part I: Exploration of alternative benzyl and privileged structure moieties.

This Letter describes the first account of the synthesis and SAR, developed through an iterative analogue library approach, of analogues of the highly selective M1 allosteric agonist TBPB. With slight structural changes, mAChR selectivity was maintained, but the degree of partial M1 agonism varied considerably.

Centrally active allosteric potentiators of the M4 muscarinic acetylcholine receptor reverse amphetamine-induced hyperlocomotor activity in rats.

Previous clinical and animal studies suggest that selective activators of M(1) and/or M(4) muscarinic acetylcholine receptors (mAChRs) have potential as novel therapeutic agents for treatment of schizophrenia and Alzheimer's disease. However, highly selective centrally penetrant activators of either M(1) or M(4) have not been available, making it impossible to determine the in vivo effects of selective activation of these receptors. We previously identified VU10010 [3-amino-N-(4-chlorobenzyl)-4, 6-dimethylthieno[2,3-b]pyridine-2-carboxamide] as a potent and selective allosteric potentiator of M(4) mAChRs. However, unfavorable physiochemical properties prevented use of this compound for in vivo studies. We now report that chemical optimization of VU10010 has afforded two centrally penetrant analogs, VU0152099 [3-amino-N-(benzo[d][1,3]dioxol-5-ylmethyl)-4,6-dimethylthieno[2,3-b]pyridine carboxamide] and VU0152100 [3-amino-N-(4-methoxybenzyl)-4,6-dimethylthieno[2,3-b]pyridine carboxamide], that are potent and selective positive allosteric modulators of M(4). VU0152099 and VU0152100 had no agonist activity but potentiated responses of M(4) to acetylcholine. Both compounds were devoid of activity at other mAChR subtypes or at a panel of other GPCRs. The improved physiochemical properties of VU0152099 and VU0152100 allowed in vivo dosing and evaluation of behavioral effects in rats. Interestingly, these selective allosteric potentiators of M(4) reverse amphetamine-induced hyperlocomotion in rats, a model that is sensitive to known antipsychotic agents and to nonselective mAChR agonists. This is consistent with the hypothesis that M(4) plays an important role in regulating midbrain dopaminergic activity and raises the possibility that positive allosteric modulation of M(4) may mimic some of the antipsychotic-like effects of less selective mAChR agonists.