L-Asparagine tert.butyl ester hydrochloride is a protected amino acid ester derived from L-asparagine in which the carboxyl group is converted to a tert-butyl ester and the amino acid side chain contains a primary amide functionality. The molecule bears an amino group on the α-carbon and an amide side chain, while the tert-butyl ester masks the carboxylate as a neutral ester and the hydrochloride form provides an ammonium chloride salt for the amino functionality. It is used as a stepwise building block in amino acid and peptide synthesis and as a substrate-like intermediate for preparing asparagine-containing peptide derivatives under conditions that require controlled handling of the carboxyl group.
CAT No: CP00332
CAS No:63094-81-5
Synonyms/Alias:L-Glutamicacidg-benzylestera-amidehydrochloride;63091-89-4;H-GLU-NH2HCL;H-GLU(OBZL)-NH2HCL;SCHEMBL11288415;MolPort-020-004-691;ACT10877;KM0701;L-Isoglutaminebenzylesterhydrochloride;BP-12449;KB-53234;H-Glu(OBzl)-NH2invertedexclamationmarkcurrencyHCl
L-Asparagine tert.butyl ester hydrochloride is an L-asparagine derivative in which the side-chain amide of asparagine remains present while the carboxylate is masked as a tert-butyl ester and the amino functionality is present as a hydrochloride salt. The molecule therefore combines a stereodefined α-amino acid core with an acid-labile tert-butyl ester handle and a side-chain amide that can participate in hydrogen bonding and selective acylation chemistry. Salt formation improves handling of the amino group during peptide coupling setup, while the tert-butyl ester strategy supports orthogonal protection patterns relative to base-stable amides and side-chain functionalities. The overall reactivity profile makes the compound suitable as a chiral amino acid intermediate for protected amino acid synthesis and downstream conversion into peptide building blocks and functionalized aspartamide motifs.
1. Protected Amino Acid Synthesis
L-Asparagine tert.butyl ester hydrochloride is used in protected amino acid synthesis workflows where an L-asparagine scaffold with a removable tert-butyl ester is required for controlled peptide coupling chemistry. The α-amino group as the hydrochloride salt can be engaged in standard coupling protocols, while the tert-butyl ester provides an acid-labile C-terminal protection that can be deprotected under conditions compatible with many side-chain protecting-group schemes. The side-chain amide enables selective derivatization when orthogonal functional group manipulation is needed, including conversion to acylated or activated asparagine analogs for subsequent assembly. Downstream, the compound supports preparation of C-terminally protected asparagine building blocks used in peptide synthesis planning and in stepwise synthesis of asparagine-containing intermediates for fine chemical production.
2. Peptide Synthesis
L-Asparagine tert.butyl ester hydrochloride serves as a peptide building block precursor for constructing peptide sequences that incorporate asparagine at defined positions. The molecule's α-amino functionality supports amide bond formation, and the tert-butyl ester enables C-terminal protection that can be removed to generate a carboxylic acid equivalent for iterative peptide elongation cycles. The stereochemistry of the L-configuration is retained through the protected intermediate stage, supporting stereochemically consistent peptide backbone assembly. The side-chain amide participates in intramolecular and intermolecular hydrogen bonding, which can influence solubility and conformational preferences during peptide synthesis and purification, making the building block relevant for producing asparagine-rich peptides and asparagine-containing fragments used in biochemical research.
3. Chemical Biology Probes
L-Asparagine tert.butyl ester hydrochloride is applicable to chemical biology research where asparagine side-chain functionality is leveraged for labeling, capture, or conjugation strategies. The unmodified side-chain amide can undergo controlled functional group transformations such as acylation or activation to introduce handles for tethering to probes, linkers, or affinity tags while preserving the asparagine recognition elements in peptide-like constructs. The tert-butyl ester protection supports intermediate stability during multi-step synthesis of conjugatable amino acid derivatives and peptide conjugates, including routes that require temporary masking of the carboxyl group. The resulting asparagine-based intermediates can be employed to generate peptide mimics and molecular probes for studying binding interactions, protein recognition, and structure-dependent behavior in biochemical assays.
4. Peptidomimetics And SAR Studies
L-Asparagine tert.butyl ester hydrochloride can be used in peptidomimetic construction and structure-activity relationship studies where asparagine-like side-chain hydrogen-bonding patterns are incorporated into non-native scaffolds. The protected amino acid form enables controlled incorporation into larger synthetic sequences, while the side-chain amide supports modeling of polar interactions that often govern receptor or enzyme recognition in SAR-driven design. The tert-butyl ester strategy supports modular synthesis of analog libraries by allowing C-terminal deprotection and subsequent coupling steps without disturbing many common protecting-group motifs. Downstream, the compound can feed into the preparation of asparagine-containing analogs and fragment units used to compare binding or activity trends across stereochemically consistent series in medicinal chemistry research.
5. Process Chemistry Intermediate
L-Asparagine tert.butyl ester hydrochloride is suitable for process chemistry intermediate preparation where robust handling of an amino acid derivative and predictable protection/deprotection behavior are required. The hydrochloride salt form can improve material manageability during scale-up operations that involve amino group activation and coupling setup, while the tert-butyl ester provides an acid-labile outlet for converting the protected intermediate into a carboxylic acid functionality when needed for downstream transformations. The retained side-chain amide reduces the need for additional side-chain protection in many synthetic routes, supporting streamlined manufacturing of asparagine-containing intermediates. The compound can therefore be employed as a chiral building block in industrial fine chemical synthesis and specialty chemical production that targets peptide-grade intermediates and asparagine-derived derivatives for further industrial conversion.
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