Compounds of the general formula (I) or its salt or a compound in which one or more atoms are replaced by their stable, nonradio-active isotopes, in particular its pharmaceutically acceptable salt; in which X is —CH2—; R is a mono- to tetra-substituted, mono- or bicyclic, unsaturated heterocyclic radical having 1 to 4 nitrogen atoms, R2 is C1-6alkyl or C3-6cycloalkyl; R3 is independently of one another H, C1-6alkyl, C1-6alkoxycarbonyl or C1-6alkanoyl; R4 is C2-6alkenyl, C1-6alkyl, unsubstituted or substituted aryl-C1-6alkyl or C3-8cycloalkyl; R5 is -Lm-R6; L is C1-6alkylene which is optionally substituted by 1-4 halogen, or a linker: formula (II) n=0, 1 or 2; m=0 or 1; R6 is a radical composed of 2 cyclic systems selected from bicyclo[x.y.z]alkyl, spiro[o.p]alkyl, mono- or bioxabicyclo[x.y.z]alkyl or mono- or bioxaspiro[o.p]alkyl, all of which may be substituted by 1-3 substituents selected from C1-6alkyl, C1-6alkoxy, cyano, halogen, C1-6alkoxy-C1-6alkyl, hydroxy-C1-6alkyl or dialkylamino, or if m=0: is also saturated C3-8heterocyclyl which comprises 1-2 oxygen atoms, substituted by 1-3 substituents selected from C1-6alkyl, C1-6alkoxy, cyano, halogen, C1-6alkoxy-C1-6alkyl, hydroxy-C1-6alkyl or dialkylamino, or if m=1: is also saturated C3-8heterocyclyl which comprises 1-2 oxygen atoms, optionally substituted by 1-3 substituents selected from C1-6alkyl, C1-6alkoxy, cyano, halogen, C1-6-alkoxy-C1-6alkyl, hydroxy-C1-6alkyl or dialkylamino; have renin-inhibiting properties and can be used as medicines for the treatment of hypertension.