合成路线1

The title compound has been prepared by solid-phase peptide synthesis on a Knorr resin. N-Fmoc-L-Phenylalanine (I) is attached to the resin by means of BOP and HOBt, producing resin (II). Deprotection of the N-Fmoc group of (II) with piperidine in DMF gives the phenylalanine-bound resin (III). Subsequent coupling with N-Fmoc-L-p-fluorophenylalanine (IV) yields the dipeptide resin (V), which is further deprotected to (VI) with piperidine in DMF. Further coupling-deprotection cycles with N-Fmoc-D-alanine (VII) and N-Fmoc-O-tert-butyl-L-tyrosine (IX) provide the peptide resins (VIII) and (X) respectively. Finally, simultaneous cleavage from the resin and side chain deprotection is accomplished by treatment with trifluoroacetic acid.