Synthesis and evaluation of potent and selective β3 adrenergic receptor agonists containing acylsulfonamide, sulfonylsulfonamide, and sulfonylurea carboxylic acid isosteres

Starting from phenethanolamine aniline leads 3a and 3b, we have identified a series of functionally potent and selective β3 adrenergic receptor (AR) agonists containing acylsulfonamide, sulfonylsulfonamide, or sulfonylurea groups within the aniline phenethanolamine series. In β3, β2, and β1 AR cAMP functional assays, 3a and other right-hand side (RHS) carboxylate analogues were found to be full agonists that were modestly selective against β1 or β2 ARs, while analogues lacking RHS acid functionality were active at β3 AR but not selective. Replacement of the carboxylate with acylthiazole and acylmethylsulfone gave potent, but only modestly selective, compounds. Increasing the size of the RHS sulfonamide substituent with phenyl or p-toluene afforded compounds with good potency and functional selectivity (β3 AR pEC50 greater than 8; β1 and β2 AR selectivity greater than 40- and 500-fold, respectively). Our SAR studies suggest that the potency and selectivity profile of the best analogues reported here is a r...