A method for the synthesis of a cyclic ornithine-proline-D-cyclohexylalanine-tryptophan- arginine pentapeptide of Formula A； wherein R1 and R2 are, independently, -H, or -C(O)R3 where R3 is -Ch2Ph, - CH2CH2Ph, -CH=CHPh, -C(NHAC)CH2Ph； the method comprising the steps of； forming a linear proline-D-cyclohexylalanine-tryptophan-arginine-ornithine pentapeptide of Formula B, attached to a polymeric resin； wherein R1 is as for Formula A, RES indicates the polymeric resin, and P1 and P2 are protecting groups； cyclising the linear pentapeptide of Formula B to form a cyclic pentapeptide of Formula C, attached to the polymeric resin； cleaving the cyclic peptide of Formula C from the resin providing a cleaved cyclic pentapeptide having a free amine group of an ornithine residue； optionally substituting the free amine group of the ornithine residue of the cleaved cyclic peptide； removing the protecting groups P1 and P2, to provide the cyclic peptide of Formula A.
