Nα-Benzyl-L-histidine (Bzl-His-OH, CAS 17451-61-5) is a protected derivative of the essential amino acid L-histidine. It features a benzyl group attached to the alpha-amino nitrogen, leaving the imidazole side chain and carboxylic acid group free. This specific protection pattern makes it a valuable chiral building block in peptide synthesis and medicinal chemistry. Its primary application is as a key intermediate in the synthesis of more complex peptides and peptidomimetics. The benzyl group serves as a common protecting group for amines, which can be removed under specific conditions (e.g., hydrogenolysis) during solid-phase or solution-phase peptide synthesis. This compound is particularly useful for introducing the histidine residue, which often plays a crucial role in enzymatic catalysis and metal binding within bioactive peptides. As a derivative of a proteinogenic amino acid, it is widely used in research focused on developing peptide-based therapeutics, enzyme inhibitors, and diagnostic agents. It is a standard item in catalogs of fine chemicals and peptide synthesis reagents for pharmaceutical and biochemical research.