A novel series of 2-(3-indolyl)alkylamino-1-(3-chlorophenyl)ethanols was prepared and evaluated for in vitro ability to stimulate cAMP production in Chinese hamster ovary cells expressing cloned human beta(3)-AR. The optically active 30a was found to be the most potent and selective human beta(3)-AR agonist in this series with an EC(50) value of 0.062nM. In addition, 30a selectivity for human beta(3)-AR