Muscarinic thioligands with cyclopentane nucleus

Area of Science:

• Medicinal Chemistry
• Pharmacology
• Drug Discovery

Background:

• Deoxamuscarine derivatives are investigated for their potential as muscarinic agonists.
• Understanding structure-activity relationships is crucial for designing selective muscarinic receptor ligands.

Purpose of the Study:

• To synthesize and evaluate thio- and benzoyl-derivatives of deoxamuscarine as muscarinic agonists.
• To determine the impact of structural modifications on muscarinic receptor binding and functional activity.
• To assess subtype selectivity for M2 and M3 muscarinic receptors.

Main Methods:

• Radioligand binding assays were employed to measure binding affinity.
• Functional tests were conducted to assess agonist activity.
• Structure-activity relationships were analyzed by comparing derivatives to deoxamuscarine.

Main Results:

• Lipophilic pocket recognition requires precise structural dimensions, with minimal tolerance for modifications.
• Substitution of the ammonium group with a sulphonium group significantly reduced muscarinic potency.
• The muscarinic sub-site accommodates bulky functions when linked via an oxygen bridge to a cyclopentane carrier.
• Esterification of the oxygen-linked moiety enhanced M2 subtype selectivity.
• Etherification of the oxygen-linked moiety increased M3 subtype selectivity.

Conclusions:

• Structural modifications of deoxamuscarine significantly impact muscarinic receptor interaction and subtype selectivity.
• Specific functionalization strategies can yield selective M2 or M3 muscarinic receptor agonists.
• These findings provide insights for the rational design of novel muscarinic receptor modulators.