Fmoc-D-Gln-OH

Fmoc-D-Gln-OH is an Fmoc-protected D-configured glutamine amino acid, featuring an Fmoc carbamate at the alpha-amino position and a free carboxylic acid for controlled peptide coupling. The side chain contains a primary amide (glutamine side chain) that can participate in hydrogen bonding and can be selectively derivatized or protected to tune reactivity during synthesis. The D stereochemistry at the alpha carbon supports incorporation of stereochemically defined D-amino acid segments into peptides and peptidomimetics, while the Fmoc group enables orthogonal base-labile deprotection under standard solid-phase peptide synthesis conditions. The combination of a protected amine, a reactive carboxyl group, and an unprotected side-chain amide makes this compound a practical chiral building block and biochemical research intermediate for downstream functionalization and scaffold construction.

1. Peptide Synthesis

Fmoc-D-Gln-OH is used in peptide synthesis workflows where a D-glutamine residue is required for stereodefined peptide building block preparation. The Fmoc-protected alpha-amino functionality supports stepwise peptide coupling, while the free carboxylic acid participates in amide bond formation after activation. The side-chain primary amide can be retained for native glutamine-like hydrogen-bonding patterns or can be temporarily protected/modified to manage chemoselectivity during multi-residue assembly. Incorporation of the D stereocenter enables access to D-amino acid-containing peptides for studies of stability, folding behavior, and sequence-dependent conformational effects, supporting both research-grade peptide analog construction and manufacturing-scale peptide intermediate preparation.

2. Peptidomimetics And SAR

Fmoc-D-Gln-OH is applied in peptidomimetic and SAR studies where glutamine-like side-chain recognition motifs are modeled with stereochemical control. The glutamine amide side chain provides a polar hydrogen-bond donor/acceptor pattern, and the D configuration can be leveraged to probe how stereochemistry influences binding-site complementarity and conformational preferences. Fmoc-based peptide coupling compatibility enables rapid generation of analog series in which the D-Gln unit is varied alongside neighboring residues. Downstream derivatization of the side-chain amide into secondary amide, urea, or other constrained functionalities can support fragment elaboration and molecular scaffold diversification for structure-function mapping in medicinal chemistry programs.

3. Chemical Biology Probes

Fmoc-D-Gln-OH serves chemical biology research by enabling incorporation of a D-glutamine residue into labeled or reactive peptide probes. The side-chain primary amide can be targeted for conjugation strategies such as controlled acylation, carbamoylation, or conversion to electrophilic intermediates for subsequent bioconjugation chemistry. The Fmoc carbamate and free carboxyl group support reliable peptide assembly, allowing the probe to be positioned at a defined sequence location for mechanistic studies of molecular recognition. D-amino acid incorporation can help tune proteolytic stability of peptide-based probes, supporting downstream generation of functional conjugates used in biochemical assays and pathway interrogation.

4. Protein Engineering

Fmoc-D-Gln-OH is utilized in protein engineering and synthetic protein design where stereochemically defined amino acid substitutions are introduced into peptide or protein segments. The protected alpha-amino group and carboxylic acid enable incorporation into engineered sequences during peptide precursor synthesis, while the glutamine side-chain amide supports polar interactions that can influence local structure and intermolecular contacts. The D stereochemistry can be used to modulate backbone geometry and resistance to enzymatic processing, supporting design of protease-resistant variants or constrained motifs. Conversion of the side-chain amide into alternative functional groups can further expand the range of interaction chemistries available for engineered biomolecules and applied protein scaffold construction.

5. Process Chemistry Intermediate

Fmoc-D-Gln-OH is suitable for process chemistry intermediate preparation in fine chemical synthesis routes that require a chiral, Fmoc-protected D-amino acid building block. The Fmoc group provides a robust protecting-group strategy for the alpha-amino functionality during coupling steps, while the free carboxylic acid supports controlled activation chemistry for peptide bond formation. The side-chain primary amide is chemically stable under typical peptide synthesis conditions yet can be selectively transformed in downstream steps to generate functionalized derivatives for further manufacturing stages. The stereochemical integrity of the D configuration supports reproducible production of D-amino acid-containing peptide intermediates used in industrial peptide manufacturing and applied biochemical reagent production where consistent stereopurity is required.

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