H-D-Thr(Bzl)-NH2 · HCl

H-D-Thr(Bzl)-NH2 · HCl is a protected threonine amino acid derivative presented as the hydrochloride salt, featuring the D-stereochemistry at the α-carbon and a benzyl-protected side-chain hydroxyl (Thr(Bzl)) alongside a free primary amino group as the salt. The benzyl ether masks the side-chain alcohol during peptide coupling and other transformations, while the salt form enhances handling and can influence solubility in polar organic and mixed solvent systems used for protected amino acid synthesis. The combination of a chiral α-amino center and an O-benzyl-protected functional group supports stereochemically defined incorporation into peptide sequences and downstream side-chain unmasking. The molecule functions as a chiral amino acid intermediate and peptide building block precursor compatible with standard amino acid derivatization and coupling workflows.

1. Protected Amino Acids

H-D-Thr(Bzl)-NH2 · HCl is applied in protected amino acid chemistry where D-threonine stereochemistry must be retained while the side-chain hydroxyl is temporarily masked as a benzyl ether. The free amino group (as the HCl salt) enables controlled conversion into activated coupling partners or peptide-ready derivatives, while the O-benzyl group suppresses side reactions such as uncontrolled hydroxyl participation during amide bond formation. Benzyl ether stability under many coupling conditions supports stepwise synthesis, and subsequent hydrogenolysis can regenerate the native threonine side-chain alcohol for functional studies or further derivatization. The resulting intermediate utility spans chiral building block preparation and protected amino acid synthesis for both research-grade peptide analog construction and process-oriented fine chemical manufacturing.

2. Peptide Synthesis

H-D-Thr(Bzl)-NH2 · HCl is suited for peptide synthesis workflows that require incorporation of a D-configured threonine residue with side-chain hydroxyl protection. The benzyl-protected hydroxyl preserves the threonine side-chain during peptide coupling, minimizing competing O-acylation and enabling selective deprotection at a chosen stage of assembly. The amino functionality can be transformed into peptide coupling-compatible forms, allowing amide bond formation at the α-amino position while maintaining stereochemical fidelity of the D-center. Downstream, deprotection yields a threonine residue suitable for subsequent modifications such as side-chain functionalization, phosphorylation-mimic chemistry, or conjugation handles in peptide-based materials and peptidomimetics.

3. Peptidomimetics And SAR

H-D-Thr(Bzl)-NH2 · HCl supports peptidomimetic construction and structure-activity relationship studies by providing a stereodefined threonine unit with an orthogonally protected side-chain alcohol. The O-benzyl group acts as a protective handle that can be removed to reveal the hydroxyl for later derivatization, enabling systematic variation of side-chain substitution patterns without perturbing earlier peptide assembly steps. D-threonine incorporation can be used to probe stereochemical effects on conformational preferences and molecular recognition in SAR-focused libraries, while the protected alcohol supports consistent synthetic access to analogs. The compound thereby functions as a chiral intermediate for generating threonine-containing peptide analogs and for preparing defined fragments used in medicinal chemistry and biochemical research.

4. Chemical Biology Conjugation

H-D-Thr(Bzl)-NH2 · HCl is utilized in chemical biology and biomolecule modification strategies where threonine side-chain hydroxyl reactivity is needed after controlled unmasking. The benzyl ether protection enables orthogonal timing: the side-chain remains protected during earlier steps such as peptide fragment assembly, linker installation, or attachment to targeting scaffolds. Hydrogenolysis or other benzyl-cleaving strategies can later regenerate the primary threonine alcohol, which can then be converted into conjugation-ready derivatives such as activated esters, linkers, or functional handles for downstream coupling chemistries. The D-configured stereocenter also supports preparation of stereochemically defined conjugates for mechanistic studies and for constructing labeled peptides used in protein interaction mapping and analytical workflows.

5. Process Chemistry Intermediates

H-D-Thr(Bzl)-NH2 · HCl is relevant to process chemistry intermediate preparation where stable protection of the threonine side-chain hydroxyl improves control over impurity formation during multistep synthesis. The benzyl-protected alcohol reduces side reactions that can arise from free hydroxyl groups under coupling and activation conditions, supporting predictable downstream transformations in amino acid derivative manufacturing routes. The hydrochloride salt form can facilitate handling and consistent dosing in chemical manufacturing operations that rely on reproducible salt formation and solvent behavior. The compound can be employed as a chiral amino acid intermediate for producing peptide building blocks and for generating protected threonine derivatives used in industrial fine chemical synthesis and specialty chemical production.

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