The<unk> tiary butyl group in<unk>  makes it more selective for β2 receptors. Since there is no hydroxy group on position 4 of the benzene ring, the molecule is less susceptible to metabolism by the enzyme catechol-O-methyl transferase.
Terbutaline
Oxymetazoline
Halofantrine
Hyoscine butylbromide
Midodrine
Erythrocrine
Bromethalin
Minaprine