Three Fmoc-phosphotyrosine derivatives with silylethyl-based phosphate protection were synthesized and evaluated for use in peptide synthesis." he stability of these derivatives toward piperidinel DMF (1: 4) treatment and their cleavability with TFA solutions were examined. On the basis of these data, the bis [(methyldiphenylsilyl) ethyll-protected Fmoc- phosphotyrosine derivative or Fmoc-Tyr (P03MDPSE&OH, was shown to be the most ...