Heterocyclic compounds and their use as angiotensin antagonists

A compound or a salt thereof of formula:

• ##STR84## wherein R.sup.1 is lower (C.sub.1-5) alkyl which may be bound through --O--, --NH-- or --S-- and which may be substituted with hydroxy, amino, N-lower (C.sub.1-4) alkylamino, N,N-di-lower (C.sub.1-4) alkylamino, halogen, lower (C.sub.1-4) alkoxy or lower (C.sub.1-4) alkylthio;
• R.sup.2 is a group of the formula:
• ##STR85## wherein i is --O-- or --S-- and j is >c=0 or >c=S;
• R.sup.3 is optionally esterified or amidated carboxyl, tetrazolyl, trifluoromethanesulfonic amide, phosphoric acid or sulfonic acid, which may be protected with optionally substituted lower alkyl or acyl and the group of the formula ##STR86## has a structure selected from the group consisting of ##STR87## wherein in addition to R.sup.1 and R.sup.2, a substituent selected from the group consisting of a halogen, nitro, cyano, an optionally substituted amino group, groups represented by the formula --U--R.sup.6, wherein U stands for a bond, --O--, --S-- or --CO--, and R.sup.6 stands for hydrogen or an optionally substituted lower alkyl group, groups represented by the formula --(CH.sub.2).sub.1 --CO--D', wherein D' stands for hydrogen, hydroxyl group, optionally substituted amino, or optionally substituted alkoxy or groups represented by the formula --OCH(R.sup.7)OCO.sup.8, wherein R.sup.7 stands for hydrogen, 1-6C straight-chain or branched lower alkyl group or a 5-7C cycloalkyl group, and R.sup.8 stands for a 1-6C straight-chain or branched lower alkyl group, a 2-8C lower alkenyl group, a 5-7C cycloalkyl group, a 1-3C lower alkyl group substituted with a 5-7C cycloalkyl group or an aryl group, a 2-3C lower alkenyl group substituted with 5-7C cycloalkyl or an aryl group, an optionally substituted aryl group, a 1-6C straight-chain or branched lower alkoxy group, a 2-8C straight-chain or branched lower alkenyloxy group, a 5-7C cycloalkyloxy group, a 1-3C lower alkoxy group substituted with 5-7C cycloalkyl or an aryl group, a 2-3C alkenyloxy group substituted with 5-7C cycloalkyl or an optionally substituted aryl group, or an aryloxy group, and l denotes 0 or 1;
• and tetrazolyl, trifluoromethanesulfonic acid amide, phosphoric acid or sulfonic acid, each optionally protected with alkyl or acyl, may be provided, wherein one or more of these substituents may optionally be substituted simultaneously on optional positions of the ring;
• wherein when two or more of these substituents exist, they may be bonded to each other to form a 5- to 6-membered optionally substituted aromatic hydrocarbon residue or a heterocyclic residue optionally containing hetero atom, taken together with the two ring-forming atoms;
• and wherein these rings may further be substituted with any of the above-described substituents,
• and excluding the compound 2-ethoxy-1-((2'-(2,5-dihydro-5-oxo-1,2,4-oxadiazol-3-yl)biphenyl-4-yl)meth yl)benzimidazole-7-carboxylic acid and its physiologically acceptable salts thereof.