Cyclotetrapeptides with pro-angiogenic properties

A compound of formula (I), or a stereoisomer thereof, or a mixture of stereoisomers thereof, or a pharmaceutically acceptable salt thereof

• cyclo[Arg-Asp-(beta-Lactam)] (I)
• wherein (beta-Lactam) is a biradical of the formula (II)
• wherein:
• the terminal NH group of the (beta-Lactam) is attached to the α-carbonyl group of the aspartic residue (Asp), and the terminal carbonyl group of the (beta-Lactam) is attached to the α-amino group of the arginine residue (Arg);
• R1, R2, R3 and R4 are radicals independently selected from the group consisting of hydrogen, (C1-C12)alkyl, (C2-C12)alkenyl, (C2-C12)alkynyl, (C3-C10)cycloalkyl, (C2-C9)heterocycloalkyl, (C6-C12)aryl, and (C5-C11)heteroaryl;
• wherein the radicals alkyl, alkenyl and alkynyl are optionally substituted with one or more substituents selected from the group consisting of halogen, —CN, —ORa, —SRa, —SORa, —SO2Ra—, —NO2, —N3, —NRaRb, —CORa, —CONRaRb, (C6-C12)aryl, and (C5-C11)heteroaryl;
• and the radicals cycloalkyl, heterocycloalkyl, aryl, and heteroaryl are optionally substituted with one or more substituents selected from the group consisting of halogen, (C1-C4)alkyl optionally substituted with one or more halogen atoms, —CN, —ORa, —SRa, —SORa, —SO2Ra—, —NO2, —N3, —NRaRb, —CORa, —CONRaRb, and 2,3,4,6-tetra-O-benzyl-α-D-mannosyl;
• or alternatively, R2 and R3 together with the carbon atom to which they are attached form a 3- to 7-membered monocyclic carbocyclic ring, partially unsaturated or saturated, optionally containing one or more heteroatoms selected from the group consisting of N, O and S, and being optionally substituted with one or more substituents selected from the group consisting of halogen, (C1-C4)alkyl optionally substituted with one or more halogen atoms, —CN, —ORa, —SRa, —SORa, —SO2Ra, —NO2, —N3, —NRaRb, —CORa and —CONRaRb;
• and
• Ra and Rb are independently H or (C1-C12)alkyl.