Pseudopeptides having an antiviral action

A pseudopeptide of formula ##STR84## in which R.sup.1 represents an amino-protective group or represents a radical of the formula R.sup.4 --NH--CO--,

• wherein
• R.sup.4 denotes cycloalkyl having 3 to 6 carbon atoms, or denotes straight-chain or branched alkyl having up to 18 carbon atoms, which is optionally substituted by hydroxyl, straight-chain or branched alkoxy having up to 4 carbon atoms, halogen, trifluoromethyl, trifluoromethoxy, cycloalkyl having 3 to 6 carbon atoms or by aryl having 6 to 10 carbon atoms, which can in turn be substituted up to twice in an identical or different manner by carboxyl, cyano, hydroxyl, halogen, perhalogenoalkyl having up to 5 carbon atoms or by straight-chain or branched acyl, alkoxy or alkoxycarbonyl having in each case up to 6 carbon atoms, or
• alkyl is optionally substituted by a group of the formula --CO.sub.2 R.sup.5,
• wherein
• R.sup.5 denotes hydrogen or straight-chain or branched alkyl or alkenyl having in each case up to 8 carbon atoms, which are optionally substituted by phenyl,
• or
• R.sup.4 denotes aryl having 6 to 10 carbon atoms, which is optionally substituted up to 3 times in an identical or different manner by carboxyl, halogen, hydroxyl, cyano, perhalogenoalkyl having up to 5 carbon atoms or by straight-chain or branched acyl, alkoxy, alkoxycarbonyl or vinylalkoxycarbonyl having in each case up to 6 carbon atoms, or
• denotes an amino acid radical of the formula ##STR85## wherein R.sup.6 and R.sup.7 are identical or different and denote hydrogen or methyl, or
• R.sup.6 and R.sup.7 together form a 5- or 6-membered saturated carbocyclic ring,
• or
• R.sup.6 denotes hydrogen or methyl
• and
• R.sup.7 denotes cycloalkyl having 3 to 8 carbon atoms or aryl having 6 to 10 carbon atoms or hydrogen, or denotes straight-chain or branched alkyl having up to 8 carbon atoms, the alkyl optionally being substituted by methylthio, hydroxyl, mercapto, guanidyl or by a group of the formula --NR.sup.9 R.sup.10 or R.sup.11 --OC--,
• wherein
• R.sup.9 and R.sup.10 independently of one another represent hydrogen, straight-chain or branched alkyl having up to 8 carbon atoms or phenyl,
• and
• R.sup.11 denotes hydroxyl, benzyloxy, alkoxy having up to 6 carbon atoms or the abovementioned group --NR.sup.9 R.sup.10,
• or the alkyl is optionally substituted by cycloalkyl having 3 to 8 carbon atoms or by aryl having 6 to 10 carbon atoms, which is in turn substituted by hydroxyl, halogen, nitro, alkoxy having up to 8 carbon atoms or by the group --NR.sup.9 R.sup.10,
• wherein
• R.sup.9 and R.sup.10 have the abovementioned meaning,
• or the alkyl is optionally substituted by a 5- to 6-membered nitrogen-containing heterocycle or indolyl, wherein the corresponding --NH-- functions are optionally protected by alkyl having up to 6 carbon atoms or by an amino-protective group,
• R.sup.8 denotes straight-chain or branched alkyl having up to 8 carbon atoms, which is optionally substituted by hydroxyl or straight-chain or branched alkoxy having up to 6 carbon atoms, or
• denotes carboxyl, allyloxycarbonyl, straight-chain or branched alkoxycarbonyl having up to 8 carbon atoms or benzyloxycarbonyl,
• R.sup.2 represents a radical of the formula --SO.sub.2 --R.sup.12,
• wherein
• R.sup.12 denotes methyl or phenyl, which is optionally substituted up to 4 times in an identical or different manner by methyl or methoxy, or denotes a radical of the formula ##STR86## R.sup.3 represents formyl or carboxyl or represents straight-chain or branched alkoxycarbonyl having up to 8 carbon atoms or represents a radical of the formula --CH.sub.2 --OR.sup.13 or --CH(OR.sup.14).sub.2,
• wherein
• R.sup.13 and R.sup.14 are identical or different and denote hydrogen, straight-chain or branched alkyl having up to 6 carbon atoms or a hydroxyl-protective group,
• if appropriate in an isomeric form, or a salt thereof.