Focused structure-activity relationship profiling around the 2-phenylindole scaffold of a cannabinoid type-1 receptor agonist-positive allosteric modulator: site-III aromatic-ring congeners with enhanced activity and solubility.
Bioorg Med Chem 2020;
28:115727. [PMID:
33065437 DOI:
10.1016/j.bmc.2020.115727]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/06/2020] [Accepted: 08/19/2020] [Indexed: 12/31/2022]
Abstract
Specific tuning of cannabinoid 1 receptor (CB1R) activity by small-molecule allosteric modulators is a therapeutic modality with multiple properties inherently advantageous to therapeutic applications. We previously generated a library of unique CB1R positive allosteric modulators (PAMs) derived from GAT211, which has three pharmacophoric sites critical to its ago-PAM activity. To elaborate our CB1R PAM library, we report the rational design and molecular-pharmacology profiling of several 2-phenylindole analogs modified at the "site-III" aromatic ring. The comprehensive structure-activity relationship (SAR) investigation demonstrates that attaching small lipophilic functional groups on the ortho-position of the GAT211 site-III phenyl ring could markedly enhance CB1R ago-PAM activity. Select site-III modifications also improved GAT211's water solubility. The SAR reported both extends the structural diversity of this compound class and demonstrates the utility of GAT211's site-III for improving the parent compound's drug-like properties of potency and/or aqueous solubility.
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