Used in peptide synthesis as a protected glutamine derivative, enabling selective amide bond formation without side reactions at the side chain. The benzyl ester group protects the carboxylic acid function, while the hydrochloride salt enhances stability and solubility in polar solvents. Commonly employed in the preparation of bioactive peptides and pharmaceutical intermediates where controlled functional group reactivity is required. Also utilized in research settings for studying amino acid metabolism and enzyme substrates involving glutamine analogs.