Fmoc-D-Lys-OAll*HCl

Fmoc-D-Lys-OAll*HCl is an Fmoc-protected D-lysine derivative presented as an HCl salt, combining a chiral lysine backbone with an orthogonally protected side-chain amine. The molecule contains an Fmoc carbamate on the alpha-amino group, a free carboxylate functionality masked as a side-chain protected form, and an OAll* (allyl-based) protecting group strategy on the lysine side-chain nitrogen that can be removed under orthogonal conditions. The D-configuration at the lysine stereocenter supports stereochemically defined peptide synthesis and unnatural amino acid incorporation for stereochemical mapping in peptide analogs. The salt form improves handling of the amine-containing intermediate and supports consistent coupling behavior in protected amino acid workflows.

1. Peptide Synthesis

Fmoc-D-Lys-OAll*HCl is used in peptide building block preparation where the Fmoc group enables standard base-mediated deprotection during solid-phase peptide synthesis. Lysine's side-chain amine, protected by the OAll* strategy, remains masked during chain assembly, reducing side reactions such as premature amide formation or uncontrolled crosslinking. The D-stereochemistry supports incorporation of D-Lys residues into peptide sequences for peptide coupling chemistry, stereochemical control, and evaluation of backbone chirality effects. Downstream, deprotection of the orthogonal side-chain group enables selective formation of lysine-derived amide, urea, or conjugation linkages in post-synthetic modification workflows.

2. Side-Chain Functionalization

Fmoc-D-Lys-OAll*HCl serves as a functionalized amino acid intermediate for side-chain derivatization where the orthogonally protected lysine ε-amine can be unveiled without disturbing the Fmoc-protected alpha-amino group during orthogonal protection/deprotection schemes. The presence of the chiral lysine core provides a defined attachment point for introducing cationic, nucleophilic, or linker-bearing substituents after peptide assembly or in solution-phase chemistry. The OAll* protecting group supports selective transformation of the ε-amino functionality into amide derivatives, sulfonamides, carbamates, or other nitrogen-containing linkages that are common in peptidomimetic construction. Resulting lysine-functionalized products can be used to generate libraries of peptide analogs and to tune molecular recognition through controlled changes in charge distribution and hydrogen-bonding patterns.

3. Bioconjugation Chemistry

Fmoc-D-Lys-OAll*HCl is applicable to bioconjugation workflows where lysine-derived amine chemistry is required for attaching peptides to biomolecules, polymers, or surfaces through amide or carbamate linkages. The orthogonal protection pattern helps maintain an Fmoc-protected alpha-amino group during intermediate handling while keeping the ε-amine masked until conjugation-ready conditions are applied. D-lysine incorporation can be used to probe stereochemical effects on conjugate stability, protease resistance, or binding orientation in chemical biology studies that rely on defined stereochemistry rather than heterogeneous lysine reactivity. The resulting conjugation-ready lysine handles support downstream formation of targeted molecular constructs used in biomolecule labeling and analytical reagent generation.

4. Drug Discovery Research

Fmoc-D-Lys-OAll*HCl supports drug discovery and SAR studies through the preparation of D-lysine-containing peptide fragments and peptidomimetic scaffolds with controlled stereochemistry. The Fmoc-protected amino acid format integrates into fragment assembly strategies that require reliable peptide coupling chemistry and predictable deprotection steps. The protected ε-amine enables systematic variation of side-chain substituents, supporting structure-activity relationship investigations that correlate charge, linker length, and hydrogen-bonding capacity with binding or permeability-relevant properties. Downstream, the compound can be converted into analog series for molecular design efforts where stereodefined lysine residues help isolate the impact of chirality on structure-function relationships.

5. Pharmaceutical Manufacturing

Fmoc-D-Lys-OAll*HCl is suitable for pharmaceutical manufacturing contexts that involve controlled synthesis of protected amino acid intermediates and peptide-based active ingredient precursors. The Fmoc protection on the alpha-amino group and the orthogonal OAll* side-chain protection strategy align with manufacturing-friendly protection/deprotection logic used to minimize side reactions during stepwise assembly. The HCl salt form can support reproducible handling of the amine-containing intermediate in process chemistry intermediate preparation, particularly where consistent material transfer and controlled reactivity are required. Downstream, the compound can be used to generate defined D-lysine-containing peptide intermediates that feed into further functionalization, purification, and final formulation-stage synthetic steps for peptide-derived materials.

6. Process Chemistry Intermediate

Fmoc-D-Lys-OAll*HCl functions as a process chemistry intermediate for fine chemical synthesis routes that require stereochemically defined lysine derivatives with orthogonal protection for selective transformations. The combination of Fmoc carbamate protection and OAll* side-chain masking supports modular manufacturing sequences in which deprotection and subsequent derivatization can be scheduled to match downstream coupling or conjugation steps. The chiral D-lysine center provides a stereopure input for generating consistent peptide building blocks and for producing D-amino acid-containing intermediates used in specialized peptide science. Resulting intermediates enable scalable preparation of functional amino acid derivatives, peptide analogs, and derivatization-ready constructs used across industrial chemical manufacturing and applied biochemical research workflows.

1. Genetic, cellular, and structural characterization of the membrane potential-dependent cell-penetrating peptide translocation pore

2. Application of human liver organoids as a patient-derived primary model for HBV infection and related hepatocellular carcinoma

3. The effect of B-type allatostatin neuropeptides on crosstalk between the insect immune response and cold tolerance

4. C-peptide and its C-terminal fragments improve erythrocyte deformability in type 1 diabetes patients

5. Immune responses to homocitrulline-and citrulline-containing peptides in rheumatoid arthritis