Used in peptide synthesis as a protected amino acid derivative, enabling selective coupling and preventing unwanted side reactions. The Boc group provides temporary protection of the amino terminus, while the methyl ether on tyrosine prevents modification of the phenolic hydroxyl during chain assembly. DCHA (dicyclohexylammonium) acts as a counterion, improving crystallinity and handling during purification. Commonly applied in solid-phase and solution-phase synthesis of complex peptides for pharmaceutical research.