Patent ID: 7071169

Claim:
A compound of the formula wherein R represents hydrogen, lower alkyl, carbocyclic or heterocyclic aryl-lower alkyl or cycloalkyl-lower alkyl; R 1 represents hydrogen, cycloalkyl, carbocyclic or heterocyclic aryl, or biaryl; alk represents lower alkylene; R 3 represents hydrogen or acyl; R 4 represents oxacycloalkyl, (thia-, oxothia- or diooxothia)-cycloalkyl, azacycloalkyl, or oxacycloalkyl-, (thia-, oxothia- or diooxothia)-cycloalkyl- or azacycloalkyl-lower alkyl; R 5 represents hydrogen or lower alkyl; R 6 represents lower alkyl, carbocyclic or heterocyclic aryl, (carbocyclic or heterocyclic aryl)-lower alkyl, cycloalkyl, cycloalkyl-lower alkyl, biaryl or biaryl-lower alkyl; R 7 represents lower alkyl, (carbocyclic or heterocyclic aryl)-lower alkyl, cycloalkyl-lower alkyl or biaryl-lower alkyl; or R 6 and R 7 , together with the carbon atom to which they are attached, represent 3- to 10-membered cycloalkylidene which may be substituted by lower alkyl or aryl-lower alkyl or may be fused to a saturated or unsaturated carbocyclic 5- to 7-membered ring; or 5- or 6-membered (oxacycloalkylidene, thiacycloalkylidene or azacycloalkylidene), each optionally substituted by lower alkyl or aryl-lower alkyl; or 2,2-norbonylidene; COOR 2 represents carboxyl or carboxyl derivatized in form of a pharmaceutically acceptable ester; a disulfide derivative derived from a said compound wherein R 3 is hydrogen; or a pharmaceutically acceptable salt thereof.