Fmoc-D-Orn(ivDde)-OH

Fmoc-D-Orn(ivDde)-OH is a D-configured, Fmoc-protected ornithine derivative bearing an ivDde-protected side-chain amine, providing orthogonal protection for peptide and amino acid chemistry. The molecule contains the Fmoc carbamate on the alpha-amino functionality and an ivDde (ivDde = 1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethylidene) group on the side-chain primary amine, enabling selective deprotection under conditions compatible with standard solid-phase peptide synthesis. The carboxylic acid remains unprotected as a free acid, supporting coupling chemistry and downstream conversion to activated esters or amide linkages. The defined stereochemistry at the ornithine center and the orthogonally protected guanidinium-like amine topology of ornithine can be leveraged to control side-chain reactivity during fragment assembly and to generate precise peptide analogs after orthogonal deprotection.

1. Peptide Synthesis

Fmoc-D-Orn(ivDde)-OH serves as an amino acid building block for peptide coupling where orthogonal protection is required to manage the alpha-amino and side-chain amine independently. The Fmoc group supports standard base-labile removal to expose the alpha-amino for iterative peptide bond formation, while the ivDde-protected side-chain amine can remain masked to prevent undesired branching or crosslinking during chain elongation. The free carboxylic acid enables activation and formation of amide bonds, supporting incorporation of D-ornithine into peptides, peptidomimetics, or cyclic frameworks. Post-coupling ivDde deprotection can unlock the side-chain amine for subsequent functionalization, generating peptides with controlled charge density and side-chain spacing relevant to peptide science and synthetic methodology development.

2. Side-Chain Functionalization

Fmoc-D-Orn(ivDde)-OH is suitable for side-chain derivatization workflows that require staged unveiling of the ornithine primary amine. The ivDde-protected side-chain nitrogen can be selectively deprotected to generate a reactive amine handle for nucleophilic substitution, acylation, sulfonylation, or formation of urea and carbamate linkages. The D-configuration and the fixed three-carbon side-chain geometry of ornithine can influence conformational preferences and electrostatic presentation in resulting conjugates, which can be relevant for chemical biology probes and peptidomimetic scaffolds. Downstream functionalized derivatives can be used as intermediates for library synthesis, linker installation, or generation of charged biomolecule analogs from a single protected amino acid precursor.

3. Bioconjugation Chemistry

Fmoc-D-Orn(ivDde)-OH can be applied to bioconjugation and biomolecule modification strategies that rely on orthogonally protected amine chemistry for controlled attachment points. The protected side-chain amine enables temporal control over conjugation, allowing selective exposure of the amine after peptide or scaffold assembly while keeping other reactive sites protected. The Fmoc-protected alpha-amino functionality supports construction of defined peptidic linkers that can be further processed into amide-linked conjugates with biomolecules or targeting motifs. Resulting D-ornithine-containing conjugation intermediates can be employed in chemical biology research where stable amide connectivity and predictable side-chain spacing are required for reproducible labeling and downstream analytical characterization.

4. Process Chemistry Intermediate

Fmoc-D-Orn(ivDde)-OH is appropriate as a chiral, orthogonally protected amino acid intermediate for fine chemical synthesis and process-oriented manufacturing of peptide building blocks. The combination of base-labile Fmoc and acid-labile or hydrazine/ketal-cleavable ivDde protection supports stepwise processing logic in which intermediate isolation can be aligned with protection-state management. The free carboxylic acid permits conversion to activated coupling forms under controlled conditions, enabling scalable peptide coupling operations and minimizing side reactions associated with unmasked amines during handling. The stereochemically defined D-ornithine framework can be carried through multi-step sequences to produce consistent peptidomimetic or peptide-grade intermediates for industrial chemical production and applied peptide manufacturing workflows.

5. Analytical Research Standards

Fmoc-D-Orn(ivDde)-OH can be used in analytical method development and reference material preparation for monitoring peptide synthesis and deprotection events. The distinct mass signatures of the Fmoc and ivDde protecting groups, together with the D-ornithine stereochemical configuration, can support LC-MS or HPLC method verification for protected amino acid incorporation, incomplete deprotection detection, and side-chain protection-state tracking. The presence of a free carboxylic acid supports formation of defined derivatives for calibration or derivatization-based quantitation strategies. D-ornithine-containing protected standards can therefore serve as practical anchors in quality control workflows for peptide building block processing and orthogonal protection chemistry studies.

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