1. Basic Info

2. Physical & Chemical Properties

Physical Properties

1. Appearance: White to off-white crystalline powder
2. Odor: Odorless
3. Solubility: Soluble in methanol, ethanol, DMF, DCM; slightly soluble in ethyl acetate; insoluble in water, aliphatic alkanes
4. Melting Point: 181–184 °C
5. Optical Rotation: [α]20/D +23±1° (c=1% in methanol)
6. Density (25℃): 1.20±0.1 g/cm3
7. Boiling Point: 572.1±50.0 °C (760 mmHg)
8. Flash Point: 299.8±30.1 °C
9. Hygroscopy: Slightly hygroscopic, must be sealed and stored at low temperature
10. Storage Temp Requirement: 2–8 °C dry sealed environment

Chemical Properties

1. Protective group structure: Two orthogonal protecting groups – Boc (tert-butoxycarbonyl) on α-amino group, benzyl (Bzl) on imidazole nitrogen of histidine side chain
2. Boc group characteristic: Stable under neutral/weak alkaline conditions; removed under mild acid (TFA/HCl) without damaging benzyl group
3. Benzyl side chain protection: Resists acidic deprotection of Boc; cleaved by catalytic hydrogenation (Pd/C + H?)
4. Carboxyl reactivity: Terminal -COOH can form amide bonds with amino groups of other amino acids for peptide chain extension
5. Chiral stability: L-type single chiral configuration, not easy to racemize under normal peptide synthesis conditions
6. Thermal stability: Stable below 170 °C; above melting point easy to decompose and lose Boc protective group
7. Photostability: Avoid long-term strong light irradiation; light exposure accelerates partial deprotection and impurity generation
8. Compatibility: Compatible with peptide synthesis solvents (DMF, DCM); incompatible with strong acid, hydrogenation catalyst, strong oxidants

3. Main Application Fields

1. Solid-phase & liquid-phase peptide synthesis core building block

   The most mainstream protected histidine monomer for Boc peptide synthesis system. The benzyl group permanently shields imidazole side chain to avoid side reactions during chain extension, improves peptide purity and synthesis yield. Widely used for synthesizing histidine-containing bioactive peptides, such as hormones, signal peptides, antigen epitope peptides.
2. Biopharmaceutical API peptide intermediate

   Raw material for synthetic polypeptide drugs including anti-tumor peptides, immunomodulatory peptides, gastrointestinal regulatory peptides; solves the problem of side-chain imidazole interference in histidine coupling reaction.
3. Enzyme substrate & biochemical research reagent

   Synthetic precursor for histidine-containing enzyme substrates, fluorescent labeled peptide probes; used for research of metalloproteinase, histidine kinase, protein-metal ion binding mechanism.
4. Chiral ligand synthesis raw material

   Derivatized to prepare imidazole-containing chiral chelating ligands for asymmetric catalytic organic synthesis and metal complex catalyst preparation.
5. Laboratory standard reference substance

   High-purity standard for HPLC/TLC detection of protected amino acids, used for quality control of peptide synthesis process.

4. Quality Specification Table