Probing the cannabinoid CB1/CB2 receptor subtype selectivity limits of 1,2-diarylimidazole-4-carboxamides by fine-tuning their 5-substitution pattern

The cannabinoid CB1/CB2 receptor subtype selectivity in the 1,2-diarylimidazole-4-carboxamide series was boosted by fine-tuning its 5-substitution pattern. The presence of the 5-methylsulfonyl group in 11 led to a greater than ∼840-fold CB1/CB2 subtype selectivity. The compounds 10, 18 and 19 were found more active than rimonabant (1) in a CB1-mediated rodent hypotension model after oral administration. Our findings suggest a limited brain exposure of the P-glycoprotein substrates 11, 12 and 21.

Graphical abstractCompound 11 showed >∼840-fold CB1/CB2 subtype selectivity whereas 6 was only 31-fold selective.Figure optionsDownload full-size imageDownload as PowerPoint slide