Synthesis, biological evaluation and molecular modeling of 2-amino-2-phenylethanol derivatives as novel β 2 -adrenoceptor agonists.

A novel series of 2-amino-2-phenylethanol derivatives were developed as β2 -adrenoceptor agonists. Among them, 2-amino-3-fluoro-5-(2-hydroxy-1-(isopropylamino)ethyl)benzonitrile (compound 2f) exhibited the highest activity (EC50 = 0.25 nM) in stimulating β2 -adrenoceptor-mediated cellular cAMP production with a 763.6-fold selectivity over the β1 -adrenoceptor. The (S)-isomer of 2f was subsequently found to be 8.5-fold more active than the (R)-isomer. Molecular docking was performed to determine the putative binding modes of this new class of β2 -adrenoceptor agonists. Taken together, these data show that compound 2f is a promising lead compound worthy of further study for the development of β2 -adrenoceptor agonists.