Heterocyclic .beta.-adrenergic agonists

A compound of the formula (I) ##STR18## the racemic-enantiomeric mixtures and optical isomers of said compounds or a pharmaceutically acceptable salt or prodrug thereof,

• wherein
• R.sup.1 is an optionally substituted phenyl, optionally substituted phenoxyalkyl having 1 to 4 carbons in the alkoxy portion, optionally substituted pyridinyl, optionally substituted pyrimidyl, optionally substituted thiazolyl or optionally substituted oxazolyl;
• where the optionally substituted moieties of R.sup.1 are optionally substituted with one to three substituents, each substituent is independently selected from the group consisting of hydroxy, fluoro, chloro, iodo, bromo, CF.sub.3, sulfonamide, (C.sub.1 -C.sub.4)alkyl, (C.sub.1 -C.sub.4)alkoxy, carboxy, hydroxyalkyl, (C.sub.1 -C.sub.4)alkoxycarbonyl, (C.sub.1 -C.sub.4)thioalkyl, sulfonyl, sulfinyl, amino, --NH--CO--(CH.sub.2).sub.a -(phenyl), --NH--CO--(C.sub.1 -C.sub.10)alkyl, --NH--SO.sub.2 --(CH.sub.2).sub.a -(phenyl) and --NH--SO.sub.2 --(C.sub.1 -C.sub.10)alkyl;
• R.sup.2 is hydrogen or (C.sub.1 -C.sub.6)alkyl;
• R.sup.3 is hydrogen or (C.sub.1 -C.sub.6)alkyl;
• R.sup.4 and R.sup.5 are each independently selected form the group consisting of hydrogen, --CO.sub.2 H, --CO.sub.2 R.sup.6, --CO.sub.2 NR.sup.6 R.sup.6, --CHO, --COR.sup.6, --CH.sub.2 OH, --CH.sub.2 OCH.sub.2 CO.sub.2 R.sup.6 and --CH.sub.2 OCH.sub.2 CH.sub.2 OR.sup.6 ;
• R.sup.6 for each occurrence is independently selected form the group consisting of hydrogen and (C.sub.1 -C.sub.4)alkyl;
• Y is oxygen or sulfur;
• Z is --(CH.sub.2).sub.n --;
• n is 1;
• R.sup.7 is hydrogen, (C.sub.1 -C.sub.10)alkyl, (C.sub.1 -C.sub.10)alkenyl, --(CH.sub.2).sub.a -(optionally substituted phenyl), --(CH.sub.2).sub.a -(optionally substituted pyridinyl), --CO--(CH.sub.2).sub.a -(optionally substituted phenyl), --CO--(C.sub.1 -C.sub.10)alkyl, --SO.sub.2 --(CH.sub.2).sub.a -(optionally substituted phenyl) or --SO.sub.2 --(C.sub.1 -C.sub.10)alkyl;
• where the optionally substituted moieties in the definition of R.sup.7 are optionally substituted with one to three substituents, each independently selected form the group consisting of hydroxy, fluoro, chloro, iodo, bromo, CF.sub.3, sulfonamide, (C.sub.1 -C.sub.4)alkyl, (C.sub.1 -C.sub.4)alkoxy, carboxy, hydroxyalkyl, (C.sub.1 -C.sub.4)alkoxycarbonyl, (C.sub.1 -C.sub.4)thioalkyl, sulfonyl, sulfinyl, amino, --NH--CO--(CH.sub.2).sub.a -(phenyl), --NH--CO--(C.sub.1 -C.sub.10)allyl, --NH--SO.sub.2 --(CH.sub.2).sub.a -(phenyl) and --NH--SO.sub.2 --(C.sub.1 -C.sub.10)allyl;
• a is 0, 1, 2, 3 or 4 provided that R.sup.4 and R.sup.5 are not both hydrogen at the same time.