Concise preparation of N(alpha)-Fmoc-N(epsilon)-(Boc, methyl)-lysine and its application in the synthesis of site-specifically lysine monomethylated peptide.

A concise preparation of N(alpha)-Fmoc-N(epsilon)-(Boc, methyl)-lysine and its application in the synthesis of site-specifically lysine monomethylated peptide is described. N (alpha)-Fmoc-N(epsilon)-(Boc, methyl)-lysine is obtained, via consecutive reductive benzylation and reductive methylation in a one-pot reaction, followed by debenzylation through catalytic hydrogenolysis and Boc protection in another one-pot reaction. A peptide containing monomethylated lysine is successfully synthesized by incorporating N(alpha)-Fmoc-N(epsilon)-(Boc, methyl)-lysine as a building block via solid-phase peptide synthesis.