Used in peptide synthesis as a protected amino acid derivative, enabling selective coupling reactions while preventing side reactions at the tyrosine hydroxyl group. The Boc (tert-butyloxycarbonyl) group provides amine protection that is stable under basic conditions but can be removed under mild acidic conditions, making it compatible with standard solid-phase and solution-phase peptide assembly. The ethyl-protected phenol group allows for orthogonal deprotection strategies, useful in complex peptide and protein construction. Commonly applied in the development of pharmaceuticals, bioactive peptides, and research compounds where stereochemical control and side-chain protection are critical.