H-D-Thr(Bzl)-OBzl · oxalate (1:1)

H-D-Thr(Bzl)-OBzl · oxalate (1:1) is a protected D-threonine derivative in which the amino functionality is present as an N-protected form (H-D-), while the side-chain hydroxyl is benzyl-protected as a Bzl ether and the carboxyl group is masked as a benzyl ester (OBzl). The molecule therefore contains a defined stereocenter at the D-threonine backbone and two benzylic protecting motifs that modulate polarity, hydrogen-bonding capacity, and coupling behavior. The oxalate counterion associates with the basic sites to form a stable crystalline salt, which can improve handling of the protected amino acid intermediate during synthesis and downstream conversions. The benzyl-protected alcohol and ester groups are compatible with standard peptide coupling workflows while remaining selectively removable under hydrogenolysis conditions, enabling controlled access to the free threonine hydroxyl and carboxyl functionalities for peptide and derivatization chemistry.

1. Peptide Synthesis

H-D-Thr(Bzl)-OBzl · oxalate (1:1) supports peptide building-block workflows where benzyl-protected side-chain hydroxyl prevents undesired acylation during amide bond formation. The D-configuration at the threonine backbone provides stereochemical control for incorporation into peptide sequences and peptidomimetic scaffolds, while the benzyl ester carboxyl protection can be used to tune reactivity during protected amino acid assembly. The N-protected amino functionality and protected carboxyl handle facilitate conversion into activated coupling partners or incorporation through established peptide coupling strategies in solid-phase or solution-phase synthesis. Downstream, deprotection can reveal the threonine hydroxyl for further functionalization, allowing generation of glyco-mimetic handles, phosphorylation analogs, or hydroxyl-bearing peptide analogs used in biochemical research and sequence optimization.

2. Side-Chain Functionalization

H-D-Thr(Bzl)-OBzl · oxalate (1:1) is well suited to synthetic routes that require controlled side-chain chemistry at the threonine hydroxyl position. The Bzl ether masks the hydroxyl to suppress competing reactions during ester/amide transformations, while preserving the stereochemical identity of the D-threonine side chain for later derivatization. Benzyl-protected groups can be removed to generate a free hydroxyl-bearing amino acid residue, which can then be converted into alternative functional motifs such as protected phosphate mimics, ether-linked substituents, or other oxygen-functional derivatives used for structure-activity relationship studies. The resulting functionalized threonine-containing intermediates can be incorporated into peptides or small molecules to probe recognition elements that depend on hydrogen-bonding and stereochemical orientation.

3. Protected Amino Acid Chemistry

H-D-Thr(Bzl)-OBzl · oxalate (1:1) functions as a chiral, benzyl-protected amino acid intermediate for protected amino acid synthesis and iterative intermediate building. The combination of benzyl ether (Thr(Bzl)) and benzyl ester (OBzl) provides orthogonal protection logic relative to other common protecting groups, supporting stepwise synthesis where selective deprotection is used to expose specific functional groups at defined stages. The oxalate (1:1) salt form can aid in reproducible handling of the protected amino acid during scale-up and can influence solubility and crystallization behavior relevant to process chemistry intermediate preparation. The protected scaffold can be transformed into downstream coupling-ready derivatives or used as a stereochemically defined precursor for generating D-threonine-containing analog libraries in fine chemical synthesis.

4. Chiral Synthesis and SAR Studies

H-D-Thr(Bzl)-OBzl · oxalate (1:1) is applicable to chiral synthesis programs that require D-amino acid incorporation for SAR studies and stereochemical mapping of peptide-like ligands. The preserved D-stereocenter at the threonine backbone enables systematic comparison of stereoisomer effects on conformational preferences, binding-site complementarity, and protease stability proxies in peptide and peptidomimetic series. The benzyl-protected hydroxyl and benzyl ester minimize side reactions during scaffold assembly, supporting reliable construction of analogs where oxygen functionality is introduced or revealed at controlled steps. The resulting D-threonine-containing compounds can be used to generate structure-defined libraries for medicinal chemistry research, enabling downstream analytical characterization and iterative optimization of functional group placement.

5. Pharmaceutical Intermediate Preparation

H-D-Thr(Bzl)-OBzl · oxalate (1:1) can serve as a process-oriented intermediate in the manufacturing of protected amino acid derivatives used for peptide-based active ingredient synthesis. The presence of stable benzyl protecting groups supports manufacturing-compatible protection strategies that reduce undesired functional group reactivity during intermediate conversions and purification operations. The oxalate salt form provides a defined counterion environment that may support consistent material handling and batch reproducibility for protected chiral building blocks. Downstream, controlled hydrogenolysis or deprotection can generate a threonine residue with a free hydroxyl suitable for subsequent coupling steps, functional group installation, or formation of final peptide intermediates used in pharmaceutical intermediate supply chains and specialty chemical production.

1. Cationic cell-penetrating peptides are potent furin inhibitors

2. TMEM16F and dynamins control expansive plasma membrane reservoirs

3. Myotropic activity of allatostatins in tenebrionid beetles

4. GLP-1, exendin-4 and C-peptide regulate pancreatic islet microcirculation, insulin secretion and glucose tolerance in rats

5. Myotropic activity and immunolocalization of selected neuropeptides of the burying beetle Nicrophorus vespilloides (Coleoptera: Silphidae)