Fmoc-L-Phe-OSu

Fmoc-L-Phe-OSu is an Fmoc-protected L-phenylalanine N-hydroxysuccinimide ester that combines a chiral amino acid core with a highly activated carboxylate leaving group. The molecule contains an Fmoc carbamate on the α-amino stereocenter, while the C-terminal side is converted to the OSu ester, enabling rapid acyl transfer under peptide-coupling and bioconjugation conditions. The phenyl side chain contributes hydrophobic and π-interaction character relevant to peptide assembly and molecular recognition, and the stereochemistry is fixed as the L-configuration at the α-carbon. The succinimidyl ester functionality is reactive toward nucleophiles such as amines and can be used as a controlled intermediate for downstream peptide building block preparation and conjugation chemistry.

1. Peptide Coupling Reagents

Fmoc-L-Phe-OSu is applied in peptide synthesis workflows where an activated C-terminal carboxylate is required for efficient amide bond formation. The Fmoc-protected α-amine supports orthogonal handling during solid-phase or solution-phase peptide construction, while the OSu ester activates the phenylalanine carboxyl group for nucleophilic acyl substitution by incoming amino components. The defined L-stereochemistry helps maintain stereochemical integrity across peptide chains, and the phenyl side chain remains available for later incorporation into sequence-dependent properties. The activated ester can serve as a reagent for preparing Fmoc-Phe-containing intermediates or for coupling steps that benefit from OSu reactivity profiles in synthetic organic chemistry.

2. Bioconjugation Chemistry

Fmoc-L-Phe-OSu is suitable for chemical biology and bioconjugation strategies that require amino-acid-derived linkers bearing a protected amino functionality. The succinimidyl ester can undergo acylation with primary amines on peptides, proteins, or amine-functional polymers, enabling attachment through the carboxylate of L-phenylalanine while the Fmoc group remains a stable handle for orthogonal deprotection when needed. The presence of a single chiral amino acid unit can help control local hydrophobicity and spacing in conjugates, which may influence recognition and labeling behavior in downstream assays. The product can be used to generate phenylalanine-containing conjugates and to prepare amide-linked intermediates for further peptide or tag assembly.

3. Protected Amino Acid Building Blocks

Fmoc-L-Phe-OSu is used as a protected amino acid derivative in manufacturing-oriented fine chemical synthesis where activated intermediates improve coupling reliability. The Fmoc carbamate provides an amino protecting-group strategy compatible with standard Fmoc deprotection logic, while the OSu ester enables conversion of the carboxyl terminus into an amide-forming electrophile without introducing additional coupling additives in some synthetic schemes. The fixed L-configuration and intact phenyl side chain support consistent incorporation of phenylalanine into peptide building blocks and sequence-defined materials. The compound can function as an intermediate for producing Fmoc-L-Phe derivatives, including downstream coupling-ready forms used in peptide building block preparation and controlled synthesis of amino-acid-based products.

4. Side-Chain Functionalization Routes

Fmoc-L-Phe-OSu is relevant to synthetic routes that treat phenylalanine as a chiral scaffold for subsequent derivatization of aromatic-containing peptide segments. The OSu ester provides a reactive handle for forming amide linkages that position the phenylalanine unit within larger constructs prior to side-chain modification strategies, such as electrophilic aromatic substitution or post-assembly functional group installation on aromatic rings. The Fmoc-protected amino functionality supports orthogonal manipulation, allowing sequence assembly or conjugate formation before any additional chemical transformations are executed. The resulting phenylalanine-containing amide intermediates can be carried forward into peptidomimetic construction, structure-activity relationship studies, or material precursor generation where aromatic functionality and stereochemical context are required.

5. Analytical Reference Standards

Fmoc-L-Phe-OSu can be employed in analytical research for method development and characterization of Fmoc-based amino acid derivatives and activated ester reactivity. The combination of a stable Fmoc chromophore and a defined OSu ester group provides identifiable analytical signatures for monitoring derivatization, coupling progress, and intermediate stability in synthetic organic chemistry. The L-phenylalanine framework contributes predictable fragmentation patterns and retention behavior in chromatographic and mass spectrometric workflows used to confirm identity and stereochemical consistency in peptide building block preparation. The compound may serve as a reference material for verifying reagent integrity and for supporting quality control of Fmoc-amino acid intermediate families used in peptide science and applied chemical manufacturing.

1. An Open-label, Single-center, Safety and Efficacy Study of Eyelash Polygrowth Factor Serum

2. Effect of Short-Term Desiccation, Recovery Time, and CAPA-PVK Neuropeptide on the Immune System of the Burying Beetle Nicrophorus vespilloides

3. Myotropic activity and immunolocalization of selected neuropeptides of the burying beetle Nicrophorus vespilloides (Coleoptera: Silphidae)

4. An Isolated TCR αβ Restricted by HLA-A* 02: 01/CT37 Peptide Redirecting CD8+ T Cells to Kill and Secrete IFN-γ in Response to Lung Adenocarcinoma Cell Lines

5. Identification, Localization in the Central Nervous System and Novel Myostimulatory Effect of Allatostatins in Tenebrio molitor Beetle