[摘要]：The b-adrenergic agonist 1 (zilpaterol) is used as prodn. enhancer in cattle. Binding expts. of sepd. enantiomers on recombinant human b2-adrenergic and m-opioid receptors and functional studies showed that the (-)-1 enantiomer accounts for essentially all the b2-adrenergic agonist activity and that it exhibits less affinity toward the m-opioid receptor than (+)-1, which is a m-opioid receptor antagonist. X-ray crystallog. revealed the abs. configuration of (-)-1 to be 6R,7R.
