NONNATURAL PHENOLIC AMINO-ACIDS - SYNTHESIS AND APPLICATION IN PEPTIDE CHEMISTRY

Several non-natural phenolic amino acids have been synthesized. t-Buty lated tyrosine and thyroxine derivatives, on one-electron oxidation, g ive persistent radicals which can be used as positional and/or spin la bels for amino acids. Two-electron oxidation of N-protected tyrosines leads to spirolactones, useful active esters for peptide coupling.