Synthesis of peptides containing DOPA (3,4-dihydroxyphenylalanine)

Proteins from coral reefs structures, eggshells, and marine mollusk adhesives all contain the amino acid 3,4-dihydroxyphenylalanine (DOPA). The insoluble nature of these materials has hampered characterization and turned our efforts toward work with small peptide mimics. In this paper, we present the syntheses of various DOPA derivatives: Boc-DOPA, Fmoc-DOPA, DOPA(TBDMS)2, DOPA(TBDPS)2, Boc-DOPA(TBDPS)2, Fmoc-DOPA(TBDMS)2, and Fmoc-DOPA(TBDPS)2 (where Boc=tert-butyloxycarbonyl, Fmoc=9-fluorenylmethyloxycarbonyl, TBDMS=tert-butyldimethylsilyl, and TBDPS=tert-butyldiphenylsilyl). These DOPA compounds were used to prepare peptides of various sequences. The synthetic procedure described provides an efficient route to DOPA-containing peptides in which sidechain deprotection and cleavage from resin can be accomplished in one step.