Peptide derivatives analogous to pepstatin, which inhibit renin and acid proteases

Abstract From the Canadian patent

Pepstatin analogs which inhibit renin and acid proteases having the formula:, in which: - R1 represents an acyl group selected from heterocyclylcarbonyl, heterocyclylalkylcarbonyl in, which the alkyl group is optionally substituted by a hydroxyl group, heterocyclylcarbonylalkylcarbonyl and heterocyclylalkenylcarbonyl. - R2 represents a lower alkyl group which is unsubstituted or substituted by a phenyl naphthyl or, cyclohexyl group;, - R3 represents a lower alkyl which is unsubstituted or substituted by a free amino group or an amino group carrying a protecting group, by a free carboxyl by a, hydroxyl group, by a lower alkylthio group by a phenyl, by a naphthyl or by an imidazol-4-yl; - R4 …