N-α,N-ε-di-Fmoc-D-lysine

N-α,N-ε-di-Fmoc-D-lysine is a D-lysine derivative bearing two orthogonally installable Fmoc protecting groups on the α-amino and ε-amino functionalities, while retaining the carboxylic acid side as a free or readily handled acid functionality depending on the supplier form. The molecule contains a stereogenic center characteristic of D-lysine, a flexible aliphatic side chain terminating in a protected primary amine, and two aromatic fluorenylmethoxycarbonyl groups that control chemoselective reactivity during peptide assembly. The bis-Fmoc pattern is designed to suppress undesired side reactions from both amino sites, enabling controlled peptide coupling and subsequent orthogonal deprotection strategies. The resulting chiral, doubly protected amino acid intermediate fits standard Fmoc-based peptide synthesis workflows and can be converted downstream into mono-protected lysine derivatives, labeled building blocks, or functionalized side-chain analogs through selective deprotection and derivatization chemistry.

1. Fmoc Peptide Synthesis

N-α,N-ε-di-Fmoc-D-lysine supports Fmoc-based peptide synthesis where both the α- and ε-amines are masked as Fmoc carbamates, reducing cross-linking and side-chain branching during chain elongation. The protected lysine backbone participates as a chiral peptide building block, with the D-configuration providing stereochemical control for peptide and peptidomimetic architectures. Fmoc removal under base conditions can be applied to generate a reactive amino site for coupling, while the remaining Fmoc group maintains orthogonality for subsequent selective side-chain functionalization. Downstream, the lysine residue can be incorporated into protected peptide sequences used for structure-activity relationship studies, protein fragment generation, and scaffold diversification in synthetic peptide chemistry.

2. Side-Chain Functionalization

N-α,N-ε-di-Fmoc-D-lysine enables side-chain derivatization workflows in which the ε-amino group is protected during early synthetic steps and later unmasked for targeted chemistry. The lysine side chain provides a primary amine handle that can be converted into amide, urea, sulfonamide, or linkage-forming motifs after controlled deprotection, supporting attachment of solubilizing groups, affinity tags, or reactive handles for molecular conjugation. The dual Fmoc protection pattern helps manage chemoselectivity by preventing premature reaction of the α-amino group while the ε-amino functionality is being manipulated. Resulting derivatives can serve as intermediates for modified peptides, peptidomimetics, and functionalized lysine-containing libraries used in biochemical research and applied synthetic organic chemistry.

3. Chemical Biology Conjugation

N-α,N-ε-di-Fmoc-D-lysine can be applied in chemical biology contexts requiring lysine-based conjugation motifs with controlled placement of amine-reactive sites. The protected ε-amino group allows staged introduction of conjugation chemistry, including formation of amide linkages to carboxylate-bearing probes, coupling to activated esters, or generation of handles for further click-type or affinity-based attachment strategies. The D-lysine stereochemistry can be used to tune peptide stability and recognition in biomolecular assays where stereochemical composition influences binding and proteolytic susceptibility. The bis-Fmoc intermediate therefore supports preparation of labeled or functionalized peptide constructs that can be used for biomolecule modification, molecular recognition studies, and reagent synthesis in research-grade workflows.

4. Unnatural Amino Acid Building Blocks

N-α,N-ε-di-Fmoc-D-lysine functions as a chiral, protected unnatural amino acid building block for constructing D-configured peptide segments and peptidomimetic frameworks. The presence of two Fmoc carbamates provides a controlled protection strategy that aligns with standard orthogonal deprotection logic, enabling stepwise exposure of α- and ε-amino groups during sequential assembly. The lysine side chain length and terminal amine geometry are particularly relevant for designing cationic or nucleophile-bearing motifs that participate in salt-bridge formation, receptor interaction mapping, or enzyme-substrate mimicry. Downstream, incorporation into peptide analogs can support structure-activity relationship studies and molecular design programs that require defined stereochemistry and protected functional groups compatible with iterative synthesis.

5. Pharmaceutical Intermediate Preparation

N-α,N-ε-di-Fmoc-D-lysine is suitable for pharmaceutical intermediate preparation where protected amino acid fragments are manufactured as controlled-input building blocks for peptide-like active ingredients or process intermediates. The bis-Fmoc protection pattern provides chemical stability during handling and supports predictable reactivity under Fmoc deprotection and peptide coupling conditions, which is relevant for process chemistry intermediate design. The chiral D-configuration and protected ε-amino group help ensure that downstream steps yield defined lysine-containing structures without uncontrolled side reactions from free amines. Resulting intermediates can be utilized to assemble controlled peptide fragments, generate standardized analytical reference materials, and support specialty chemical production of stereochemically defined amino acid derivatives.

6. Analytical Research Standards

N-α,N-ε-di-Fmoc-D-lysine can be employed to prepare analytical research standards and method development materials for characterizing lysine-containing peptides and amino acid derivatives. The double Fmoc pattern provides strong chromatographic distinguishability and well-defined deprotection behavior, facilitating LC-MS or HPLC method tuning for protected and partially deprotected lysine species. D-stereochemistry contributes to stereospecific separation and identity confirmation when analyzing peptide mixtures or synthetic intermediates containing chiral amino acid residues. Downstream, the compound can serve as a reference precursor for generating mono-Fmoc or deprotected lysine standards, supporting quality control of peptide synthesis workflows and analytical characterization of amino acid derivatization products.

1. Cationic cell-penetrating peptides are potent furin inhibitors

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

3. Characterization of Novel P-Selectin Targeted Complement Inhibitors in Murine Models of Hindlimb Injury and Transplantation

4. Adipose tissue is a key organ for the beneficial effects of GLP-2 metabolic function

5. Multifunctional peptide-oligonucleotide conjugate promoted sensitive electrochemical biosensing of cardiac troponin I