Fmoc-protected phenylalanine (I) is attached to Rink resin by means of DCC and HOBt coupling, to give the amino acid-resin complex (II). Then, N-Fmoc protecting group is removed with piperidine in DMF to afford (III). This is submitted to further sequential amino acid coupling and deprotection cycles with Fmoc-phenylalanine (I) and alpha-Fmoc-omega-pmc-D-arginine (VI) to yield in turn resins (V) and (VII), respectively.

Compound (VII) is submitted to amino acid coupling and deprotection cycle with O-t-Bu-alpha-Fmoc-tyrosine (IX), to yield resin (XI). Finally, acidic treatment of (XI) with trifluoroacetic acid in anisole and dichloromethane simultaneously effects deprotection of the O-tert-butyl and N-2,2,5,7,8-pentamethylchroman-6-sulfonyl (Pmc) groups, and liberates the peptide amide from the resin.