Synthesis and Pharmacological Evaluation of 1-Phenyl-3-Thiophenylurea Derivatives as Cannabinoid Type-1 Receptor Allosteric Modulators.

We previously reported diarylurea derivatives as cannabinoid type-1 receptor (CB) allosteric modulators, which were effective in attenuating cocaine-seeking behavior. Herein, we extended the structure-activity relationships of PSNCBAM-1 () at the central phenyl ring directly connected to the urea moiety. Replacement with a thiophene ring led to with improved or comparable potencies in calcium mobilization, [S]GTPγS binding, and cAMP assays, whereas substitution with nonaromatic rings led to significant attenuation of the modulatory activity. These compounds had no inverse agonism in [S]GTPγS binding, a characteristic that is often thought to contribute to adverse psychiatric effects. While had good metabolic stability in rat liver microsomes, it showed modest solubility and blood-brain barrier permeability. Compound showed an insignificant attenuation of cocaine seeking behavior in rats, most likely due to its limited CNS penetration, suggesting that pharmacokinetics and distribution play a role in translating the in vitro efficacy to in vivo behavior.