Used in peptide synthesis as a protected histidine derivative, enabling selective coupling in solid-phase peptide synthesis. The Fmoc group allows for mild base deprotection, while the Boc group protects the imidazole side chain, preventing unwanted reactions. The counterion (CHA) improves crystallinity and handling. Commonly applied in the production of therapeutic peptides, research reagents, and biochemical probes where precise sequence control is required.