I have shown that the phenolic hydroxy groups can be replaced by the acidic alkyl or arylsulfonamide substituents (soterenol, IC) or similar groups (carbuterol, ld) without altering the a and/? activities. However, a catechol-like function is certainly not an indispensable feature, since high/?-adrenergic activity can be exhibited by 3, 5-dihydroxy derivatives (terbutaline, le)
