Used in peptide synthesis as a protected amino acid derivative, particularly for introducing phenylalanine with a nitro group at the para position. The ethyl ester group enhances solubility in organic solvents, facilitating coupling reactions. The nitro group can serve as a precursor for further chemical modifications, such as reduction to an amine. Commonly employed in research to study enzyme-substrate interactions or to develop peptide-based drugs. The hydrochloride salt form improves stability and handling during storage and reactions.