H-D-Lys(Aloc)-OH

H-D-Lys(Aloc)-OH is a protected amino acid derivative in which the L-lysine side chain bears an allyloxycarbonyl (Aloc) protecting group on the ε-amino functionality, while the α-amino group is present as the free amino acid in the hydrochloride-free form indicated by the H- prefix and the carboxylic acid remains unprotected as the primary acid. The molecule contains a stereogenic center at the α-carbon, maintaining D-lysine configuration (D-lysine backbone) with a flexible aliphatic side chain that can be selectively activated for coupling chemistry. The Aloc carbamate is designed for orthogonal deprotection relative to common peptide acid-labile protecting groups, enabling programmed removal under conditions compatible with peptide backbones. The combination of a carboxylic acid handle and a protected ε-amine supports controlled peptide bond formation and downstream functionalization of lysine side-chain chemistry.

1. Peptide Synthesis

H-D-Lys(Aloc)-OH is used in peptide building and solid-phase peptide synthesis workflows where lysine incorporation requires selective ε-amino protection during chain assembly. The protected ε-amino group as an Aloc carbamate suppresses side reactions during Nα coupling, while the free carboxylic acid and α-amino functionality enable standard amino acid coupling strategies for backbone elongation. Orthogonal Aloc deprotection can be applied after chain assembly to expose the lysine ε-amine for subsequent peptide branching, cyclization, or conjugation steps. The resulting lysine residue can be carried forward into peptide analog construction with controlled side-chain availability for later derivatization.

2. Side-Chain Functionalization

H-D-Lys(Aloc)-OH supports amino acid derivatization and side-chain modification strategies that rely on post-synthetic exposure of the lysine ε-amine. The Aloc protecting group provides a removable handle that can be used to time the introduction of functional groups such as amide-forming acyl substituents, sulfonamides, ureas, or linker attachments for bioconjugation chemistry. The D-lysine stereochemistry can be retained through the protection/deprotection sequence to generate stereodefined lysine-containing scaffolds for structure-activity relationship studies and chemical biology probes. Downstream functionalization of the liberated ε-amine enables formation of reactive intermediates and stable conjugates used in peptide mapping and molecular recognition experiments.

3. Bioconjugation Chemistry

H-D-Lys(Aloc)-OH is applicable to bioconjugation and chemical biology workflows that require lysine-bearing linkers with orthogonally protected amines. The Aloc-protected ε-amino group can be maintained during coupling to peptide carriers or targeting motifs, reducing off-target crosslinking during intermediate handling. Deprotection can generate a primary amine suitable for conjugation chemistries such as amide coupling, reductive amination, or carbamate/urea formation with electrophilic partners. The stereodefined lysine side chain supports reproducible linker placement in biomolecule labeling and peptide-based affinity reagents, aligning amino acid chemistry with downstream conjugate synthesis.

4. Process Chemistry Intermediate

H-D-Lys(Aloc)-OH is suitable as a chiral amino acid intermediate for process chemistry intermediate preparation where orthogonal protecting-group design is required for scalable peptide-manufacturing routes. The presence of a carboxylic acid and a protected ε-amine allows the compound to function as a controlled input for protected amino acid synthesis and for stepwise assembly of lysine-containing sequences. The Aloc carbamate structure provides a predictable protection state that can be carried through coupling operations and then removed to reveal a reactive amine without perturbing other protecting groups that may be present on peptide substrates. The compound's defined stereochemistry and protection pattern can be leveraged to streamline downstream manufacturing of protected lysine-containing building blocks and peptidomimetic intermediates.

5. Analytical Research Standards

H-D-Lys(Aloc)-OH can be employed in analytical research and method development where protected lysine derivatives serve as reference materials for chromatographic and mass spectrometric characterization. The Aloc-protected ε-amine and free carboxylic acid generate a distinct chemical signature that supports monitoring of protection state, deprotection progress, and impurity profiles in protected amino acid chemistry. The D-lysine stereochemical identity enables stereospecific tracking in workflows that compare lysine epimers or stereochemically defined peptide fragments. The compound can also serve as a starting point for generating labeled or derivatized standards used to validate peptide coupling chemistry, side-chain modification steps, and orthogonal deprotection sequences.

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