合成路线1

The title compound is prepared by solid-phase peptide synthesis starting from N-Fmoc-L-phenylalanine attached to Wang resin (I). Deprotection of (I) with piperidine in NMP removes the N-Fmoc group, yielding the phenylalanine resin (II). Coupling of (II) with N-trityl glycine (III) in the presence of PyBOP and HOBt, followed by acidic cleavage of the N-trityl group furnishes the dipeptide derivative (IV). To this is assembled N-Fmoc-S-trityl-D-penicillamine (V), followed by deprotection with piperidine in NMP, to produce resin (VI). Subsequent coupling of (VI) with N-Cbz-O-benzyl-L-tyrosine (VII) leads to the protected tetrapeptide (VIII). Removal of the S-trityl protecting group of (VIII) employing trifluoroacetic acid provides thiol (IX).