Used in peptide synthesis as a protected, N-methylated serine derivative, enabling selective coupling and preventing side reactions. The Boc group protects the N-methyl amine, while the methyl ester masks the carboxylic acid, allowing stepwise assembly of complex peptides. The N-methyl modification enhances metabolic stability and conformational control in modified peptides. The free hydroxyl side chain on serine permits further selective functionalization. Commonly applied in pharmaceutical research and development of bioactive peptides.