H-L-Lys(Cm)-OH

H-L-Lys(Cm)-OH is an L-lysine derivative bearing a C-terminal carboxylic acid and an epsilon-amine side chain masked as a C-methyl (Cm) protecting group. The molecule retains the lysine stereocenter at the alpha carbon, providing a well-defined chiral amino acid scaffold for peptide coupling chemistry. The presence of a free alpha-carboxylic acid and a protected side-chain amine creates a controlled reactivity profile in which amide bond formation can be directed primarily through the alpha functionality while side-chain derivatization is postponed until deprotection. The Cm group is designed to withstand common peptide synthesis conditions and can be removed under appropriate orthogonal strategies, enabling downstream functionalization of the lysine side chain for peptide and bioconjugation workflows.

1. Protected Amino Acids

H-L-Lys(Cm)-OH is used in protected amino acid synthesis and peptide building block preparation where orthogonal functional group control is required. The protected epsilon-amine (Cm) suppresses uncontrolled side reactions during coupling, while the alpha-carboxylic acid and alpha-amino functionality support standard peptide coupling chemistry. Cm protection provides a practical handle for staged deprotection, allowing lysine side-chain amide formation or further derivatization to be introduced at a chosen step. The resulting protected amino acid intermediate can be applied to the assembly of peptides and peptide analogs that require lysine side-chain functional group timing.

2. Peptide Synthesis

H-L-Lys(Cm)-OH serves as a lysine residue precursor for solid-phase or solution-phase peptide synthesis where selective lysine side-chain chemistry is needed. The L-lysine backbone stereochemistry supports incorporation into peptide sequences with defined three-dimensional geometry, while the Cm-protected epsilon-amine limits branching and side-chain crosslinking during chain elongation. The free carboxylic acid enables formation of peptide bonds through controlled activation and coupling at the alpha position, and the protected side chain can later be converted into amide, carbamate, or other nitrogen-containing linkages. Cm-protected lysine residues are therefore suitable for constructing peptides with delayed side-chain modification, including sequences that require orthogonal protection for later conjugation or SAR-driven analog generation.

3. Side-Chain Functionalization

H-L-Lys(Cm)-OH is applied in side-chain functionalization strategies that convert lysine into chemically addressable motifs after peptide assembly or in late-stage derivatization. The Cm-protected epsilon-amine provides a stable nitrogen unit that can be unveiled to enable nucleophilic substitution, acylation, or coupling to electrophiles bearing carbonyl, activated ester, or isothiocyanate-like functionalities. The lysine side-chain amine can then be used to install tags for biochemical assays, to generate charged or zwitterionic variants for binding studies, or to introduce linkers for bioconjugation. Downstream derivatives produced from H-L-Lys(Cm)-OH can function as intermediates for peptidomimetics and as modular components in synthetic organic chemistry routes requiring controlled amine unveiling.

4. Chemical Biology Labeling

H-L-Lys(Cm)-OH can be employed in chemical biology research workflows that require lysine-specific labeling chemistry with controlled timing. The Cm-protected epsilon-amine reduces off-target labeling during peptide synthesis and enables a defined conjugation point once deprotection is performed. The L-lysine scaffold supports incorporation into peptides used as recognition elements, affinity probes, or substrate mimics, where side-chain amine chemistry governs labeling density and attachment geometry. The resulting labeled peptide or lysine-functionalized intermediate can be utilized for molecular recognition studies, pull-down reagents, and analytical probe generation in biochemical research.

5. Pharmaceutical Intermediate Preparation

H-L-Lys(Cm)-OH is relevant to pharmaceutical intermediate preparation and fine chemical synthesis where protected amino acids are manufactured as controlled building blocks for active pharmaceutical ingredient (API) related intermediates. The combination of L-lysine stereochemistry with a protected epsilon-amine supports reproducible downstream transformations into lysine-containing fragments, including amide-forming intermediates and nitrogen-functionalized linkers used in medicinal chemistry. Cm protection provides a process-compatible strategy for suppressing undesired side reactions during scale-up steps that involve coupling, purification, and intermediate handling. The compound can therefore be used as a chiral amino acid intermediate for constructing lysine-bearing scaffolds and for producing defined peptide-like structures used in process chemistry and applied synthetic development.

6. Bioconjugation Chemistry

H-L-Lys(Cm)-OH is suitable for bioconjugation chemistry where lysine side-chain amine reactivity is required but must be controlled to avoid premature conjugation. The protected epsilon-amine enables preparation of lysine-containing conjugation partners that can be activated or deprotected to introduce a single, predictable attachment site. The alpha-carboxylic acid and amino acid framework support incorporation into peptide conjugates and linker-bearing constructs that maintain stereochemical integrity of the lysine residue. The ability to stage deprotection and subsequent amide or urea formation supports downstream generation of conjugates for analytical standards, affinity reagents, and functional biomolecule modification workflows.

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