H-D-Abu-OtBu · HCl

H-D-Abu-OtBu · HCl is the hydrochloride salt of an N-unprotected D-amino acid derivative, where D-2-aminobutyric acid (D-Abu) bears a tert-butyl ester (OtBu) that masks the carboxylate as a acid-labile protecting group. The D stereocenter provides defined chiral configuration for stereoselective peptide coupling and for preparing enantiomerically controlled analogs in peptidomimetic and chemical biology workflows. The hydrochloride counterion stabilizes the free amine as an ammonium salt, which can influence solubility and handling during protected amino acid synthesis or downstream activation chemistry. The combination of a chiral amino group and an ester-protected carboxyl functionality enables conversion into activated coupling partners, selective deprotection to regenerate the free acid, and incorporation into peptide chains or side-chain-modified intermediates.

1. Protected Amino Acid Synthesis

H-D-Abu-OtBu · HCl is used in protected amino acid chemistry and peptide building block preparation where a carboxyl-protecting tert-butyl ester supports controlled functional group transformations. The D-Abu backbone provides a stereodefined amino acid core, while the OtBu ester can be selectively removed under acid conditions to reveal the carboxylic acid for subsequent coupling or for conversion into salts and activated derivatives. The hydrochloride form helps maintain the amine in a defined protonation state during intermediate handling, which can be leveraged when designing stepwise protection/deprotection sequences. Downstream, the compound can serve as a chiral intermediate for producing N-protected derivatives, activated esters, or coupling-ready acids used in fine chemical synthesis.

2. Peptide Synthesis

H-D-Abu-OtBu · HCl is suitable for peptide synthesis workflows that require incorporation of a D-amino acid residue into linear peptides, cyclic peptides, or peptidomimetic scaffolds. The tert-butyl ester acts as a temporary C-terminal protection element that can be carried through coupling steps and then deprotected to generate a reactive carboxyl handle for chain extension, cyclization, or end-group modification. The D stereochemistry enables access to stereochemically defined peptide analogs that can be used to probe backbone effects, protease resistance patterns, and conformational preferences without altering the side-chain topology. The hydrochloride salt form supports practical handling as a chiral building block when assembling protected amino acid derivatives into larger peptide structures.

3. Peptidomimetics And SAR Studies

H-D-Abu-OtBu · HCl is applied in peptidomimetic construction and structure-activity relationship studies where D-amino acid incorporation tunes backbone rigidity, steric presentation, and metabolic stability. The amino acid core provides a residue that can be positioned as a stereodefined element within peptide-like frameworks, while the OtBu ester enables controlled generation of carboxyl functionalities for fragment assembly or late-stage diversification. The ability to switch between ester-protected and free-acid forms supports iterative synthesis of analog libraries, including C-terminal modifications and conjugation-ready derivatives. The resulting D-configured amino acid units can be integrated into SAR-focused molecular design campaigns aimed at mapping how stereochemistry and functional group placement influence binding-relevant conformations.

4. Chemical Biology Labeling

H-D-Abu-OtBu · HCl can be used in chemical biology research to generate amino acid-based intermediates for labeling, affinity tags, and probe construction that rely on controlled functional group exposure. The OtBu ester provides a protected carboxyl group that can be converted to a free acid for subsequent derivatization into coupling handles such as activated carboxylates, amide-forming intermediates, or linker-bearing derivatives. The D configuration supports stereochemically defined incorporation into peptide probes, which can be important when distinguishing stereoisomer-specific recognition events in biochemical assays. The hydrochloride salt can facilitate reproducible intermediate preparation for downstream conjugation chemistry, supporting the synthesis of labeled biomolecule analogs and reagent standards.

5. Pharmaceutical Intermediate Preparation

H-D-Abu-OtBu · HCl serves as a chiral amino acid intermediate in pharmaceutical intermediate preparation where protected carboxyl functionality and stereochemical control are required for scalable synthetic routes. The tert-butyl ester can be used as a process-compatible protecting group strategy to manage chemoselectivity during multi-step synthesis, including conversion to activated acids, ester exchange, or incorporation into larger fragments. The D-amino acid stereocenter enables preparation of stereodefined intermediates used in the synthesis of peptidic or peptidomimetic drug candidates and related research compounds. The hydrochloride salt form supports handling and can be integrated into manufacturing-oriented workflows that require controlled salt formation and predictable reactivity profiles for downstream transformations.

6. Process Chemistry And Fine Chemical Synthesis

H-D-Abu-OtBu · HCl is applicable to process chemistry and fine chemical synthesis as a chiral building block that supports stepwise protection management and intermediate isolation. The OtBu ester provides a robust, acid-labile protecting group that can be carried through coupling or derivatization steps, then removed to regenerate the carboxylic acid for subsequent transformations such as activation, salt formation, or coupling to amines. The unprotected amine as a hydrochloride salt supports defined protonation behavior, which can be leveraged to control reactivity during synthetic planning and to reduce side reactions associated with free-base amino acids. The compound's clear stereochemical identity and functional group complementarity make it suitable for manufacturing intermediate preparation and for constructing stereocontrolled amino acid derivatives used across applied chemical synthesis programs.

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