The present invention relates to compounds of the Formula (I), in which R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, X1, X2, X3 and X4 have the meanings indicated in the claims, and which are valuable pharmacologically active compounds. They are reversible inhibitors of the interaction between the plasma protein von Willebrand factor (vWF) and the blood platelet receptor glycoprotein Ib-IX-V complex (GPIb), and are suitable, for example, for the therapy and prophylaxis of athero-thrombotic diseases. The invention furthermore relates to processes for the preparation of compounds of the Formula (I), their use, in particular as active ingredients in medicaments, and pharmaceutical compositions comprising them.
