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 β3-AR. The optically active 30a was found to be the most potent and selective human β3-AR agonist in this series with an EC50 value of 0.062 nM. In addition, 30a selectivity for human β3-AR was 210-fold and 103-fold that for human β2-AR ...