H-Thr(Bzl)-OBzl · oxalate (1:1)

H-Thr(Bzl)-OBzl · oxalate (1:1) is a protected threonine derivative featuring an N-terminal hydrogen on a threonine backbone, a benzyl ester at the carboxylate (OBzl), and benzyl protection on the side-chain hydroxyl (Thr(Bzl)), with an oxalate counterion providing a stable salt form for handling. The chiral threonine stereocenter is retained in the protected amino acid architecture, while the benzyl groups mask the primary alcohol functionality and modulate acid-base behavior during peptide coupling and downstream transformations. The benzyl-protected ester and side-chain ether-like protection enable controlled deprotection strategies, typically via hydrogenolysis or strong acid/oxidative conditions depending on the protecting-group set. This structure functions as a peptide-compatible chiral amino acid ester and as a derivatization intermediate for building threonine-containing motifs in synthetic and biochemical workflows.

1. Peptide Synthesis

H-Thr(Bzl)-OBzl · oxalate (1:1) is applied in peptide building-block preparation where threonine residues must be incorporated with orthogonal protection of the side-chain hydroxyl. The benzyl ester (OBzl) and benzyl-protected side-chain hydroxyl (Thr(Bzl)) reduce undesired side reactions during amide bond formation, while the preserved stereochemistry supports stereodefined incorporation into growing peptide chains. The N-protected amino acid ester format can be used for peptide coupling chemistry that benefits from controlled activation of the carboxylate equivalent, followed by selective deprotection to reveal the native threonine functionality. Downstream peptide analogs and protected peptide intermediates generated from this chiral ester can be used for mapping phosphorylation-like motifs, conformational effects of threonine, and sequence-dependent reactivity in peptide science.

2. Protected Amino Acids

H-Thr(Bzl)-OBzl · oxalate (1:1) serves as a protected amino acid synthesis intermediate for managing functional-group reactivity in multistep organic synthesis. The benzyl-protected side-chain hydroxyl and benzyl ester mask hydrogen-bonding and nucleophilicity that would otherwise compete with coupling reagents or protection steps, while the oxalate salt form can improve practical handling of the amino acid derivative. Deprotection of the benzyl groups can be leveraged to access free threonine alcohol functionality for subsequent derivatization, including conversion to activated intermediates for further functional group installation. The resulting free or reprotected threonine derivatives can then be carried into peptide coupling, fragment elaboration, or stereodefined chiral intermediate sequences used in fine chemical synthesis.

3. Bioconjugation Chemistry

H-Thr(Bzl)-OBzl · oxalate (1:1) can be used in chemical biology workflows that require threonine-functional handles for conjugation chemistry and biomolecule modification. The benzyl-protected hydroxyl provides a protected site that can be unveiled under controlled conditions to generate a reactive alcohol for subsequent attachment strategies, such as forming linkers or enabling controlled attachment chemistries to proteins, peptides, or polymeric scaffolds. The chiral threonine backbone supports incorporation into peptide-based targeting motifs and maintains stereochemical fidelity when building conjugatable constructs. Oxalate salt formation helps stabilize the amino acid derivative during intermediate storage and can facilitate consistent downstream processing in synthetic sequences that culminate in labeled or functionalized biomolecules.

4. Peptidomimetics And SAR Studies

H-Thr(Bzl)-OBzl · oxalate (1:1) is suitable for constructing threonine-containing peptidomimetic scaffolds used in structure-activity relationship studies and molecular design campaigns. The protected side-chain hydroxyl enables controlled elaboration into analogs where the alcohol group participates in hydrogen bonding or stereoelectronic effects, while the benzyl-protected ester and masked hydroxyl help maintain chemoselectivity during scaffold assembly. Selective deprotection can provide access to the native threonine alcohol for further functionalization into constrained or substituted motifs that probe binding interactions. The chiral, protected amino acid architecture supports generation of stereodefined analog libraries that can be used to evaluate how threonine stereochemistry and side-chain functionality influence molecular recognition.

5. Pharmaceutical Manufacturing Intermediates

H-Thr(Bzl)-OBzl · oxalate (1:1) can be incorporated into process chemistry routes where threonine-containing intermediates must be manufactured with controlled protection strategy and predictable deprotection behavior. The benzyl-protected ester and side-chain hydroxyl reduce side reactions during coupling and purification steps, supporting scalable synthesis of peptide intermediates and amino acid derivative fragments. Oxalate salt formation can improve reproducibility in solid handling and intermediate transfer, while the chiral threonine center remains intact through protected transformations. Downstream, this material can serve as a feedstock for preparing protected peptide segments, intermediate building blocks for active pharmaceutical ingredient synthesis, and chemically defined precursors used in industrial fine chemical production.

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