Fmoc-D-Orn(N3)-OH

Fmoc-D-Orn(N3)-OH is an Fmoc-protected D-ornithine derivative bearing an azide-functionalized side chain, combining a chiral, nonproteinogenic amino acid scaffold with an orthogonally reactive handle for downstream conjugation. The molecule contains an Fmoc carbamate on the α-amino group, a free carboxylic acid for peptide coupling, and a D-configured stereocenter that governs stereochemical outcomes in peptide assembly and side-chain transformations. The ornithine backbone provides a three-carbon side chain terminating in an N3 azide, which can participate in chemoselective azide-alkyne cycloaddition or be reduced to a primary amine for further derivatization. The azide and carboxylic acid functional groups enable controlled orthogonal chemistry while the Fmoc group supports standard solid-phase or solution-phase peptide synthesis workflows.

1. Peptide Synthesis

Fmoc-D-Orn(N3)-OH is applied in peptide building workflows where a D-ornithine residue with a pendant azide is required for sequence-defined labeling or post-assembly modification. The Fmoc-protected α-amine supports iterative peptide coupling while the free carboxylic acid participates in amide bond formation using common peptide coupling strategies. The D stereochemistry can be leveraged to tune conformational preferences and proteolytic stability in peptide analogs, while the side-chain azide remains orthogonal to many peptide-manipulation conditions. The resulting azide-bearing peptides can be carried forward to click-type functionalization, enabling site-specific conjugation to probes, linkers, or polymeric tags in peptide science and chemical biology.

2. Bioconjugation Chemistry

Fmoc-D-Orn(N3)-OH is used as a chiral azide-containing amino acid intermediate for constructing bioconjugation-ready linkers and labeled biomolecules. The side-chain N3 group functions as a highly chemoselective azide handle suitable for azide-alkyne cycloaddition with alkyne-bearing tags, surfaces, or affinity reagents. The Fmoc-protected amino acid format allows incorporation into peptides or peptidomimetics that present the azide at a defined position relative to other functional residues. D-configuration can be exploited to modulate stability and binding behavior of the conjugate scaffold, supporting downstream generation of labeled constructs for biochemical research and analytical development.

3. Protected Amino Acid Chemistry

Fmoc-D-Orn(N3)-OH is relevant to protected amino acid synthesis planning where orthogonal functional group management is required for multi-step derivatization. The Fmoc carbamate protects the α-amino functionality during peptide coupling and intermediate handling, while the carboxylic acid remains available for controlled activation and coupling chemistry. The azide side chain provides a protected-reactive motif that can be retained through peptide assembly and then transformed in a later stage, such as reduction to a primary amine or conversion to other azide-compatible derivatives. The combination of chiral D-ornithine stereochemistry with orthogonal protection supports reproducible preparation of functionalized amino acid derivatives and peptide intermediates for fine chemical synthesis.

4. Peptidomimetic Construction

Fmoc-D-Orn(N3)-OH is employed in peptidomimetic and non-natural peptide scaffold design where side-chain azide functionality enables modular attachment of pharmacophore mimics or solubilizing groups. The ornithine side chain length and terminal azide support spatially defined functionalization, enabling construction of analog libraries with controlled linker geometry. The Fmoc-protected α-amino group facilitates incorporation into peptidomimetic sequences using standard coupling chemistry, while the D stereocenter can be used to tune backbone stereochemistry and reduce susceptibility to enzymatic degradation. The resulting azide-bearing peptidomimetics can be further diversified into conjugates, crosslinkers, or SAR-focused analogs through orthogonal azide transformations.

5. Process Chemistry Intermediate

Fmoc-D-Orn(N3)-OH is suitable for industrial chemical manufacturing routes that require a chiral, protected amino acid intermediate with a built-in functional handle for downstream conversion. The Fmoc protection strategy supports stable handling during synthesis and purification, while the free carboxylic acid enables conversion into activated derivatives for controlled amide formation in larger-scale peptide or peptidomimetic production. The azide functionality can be used as a process-compatible intermediate for later-stage derivatization steps, including click-ready labeling or transformation into amine-bearing intermediates for further functional group elaboration. The stereochemically defined D-ornithine core helps maintain consistent product identity across batches, supporting reproducible generation of functionalized peptide building blocks and specialty chemical intermediates.

6. Analytical Research Standards

Fmoc-D-Orn(N3)-OH is applied in analytical research as a defined chiral amino acid standard and as a precursor for generating azide-tagged reference materials. The combination of Fmoc protection and a terminal azide enables preparation of labeled peptide fragments that can serve as internal standards or calibration components for LC-MS-based quantification and method development. The D configuration supports stereospecific analysis when distinguishing enantiomeric amino acid derivatives or when monitoring stereochemical integrity during peptide synthesis. The azide side chain further allows conversion into alternative detectable forms, supporting downstream derivatization strategies for analytical workflows in biochemical research and quality control of peptide intermediates.

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