Used as a key intermediate in the synthesis of complex peptides and antibiotics, particularly in the preparation of naturally occurring antimicrobial peptides. Its protected functional groups allow selective deprotection and coupling in solid-phase peptide synthesis, making it valuable for constructing peptide chains with specific sequences. Commonly employed in pharmaceutical research for developing peptide-based drugs, especially those requiring precise side-chain modifications. The hydrochloride salt form improves stability and handling during synthesis.