The synthesis and evaluation of a novel series of 1,7-cyclized indole-based human adrenergic receptor (beta3-AR) agonists are reported. The synthesis of a variety of 1,7-cyclized indole part was accomplished by the Mitsunobu reaction or a ring closing metathesis (RCM) reaction. SAR studies revealed that expansion of the ring size resulted in considerable selectivity against the beta1- and beta2-ARs