Fmoc-Nle-OPfp is an Fmoc-protected amino acid derivative of norleucine bearing an OPfp (pentafluorophenyl ester) functional group on the side-chain carboxyl equivalent, placing it within the class of protected amino acid activated esters used for peptide-related coupling chemistry. The molecule contains an Fmoc carbamate on the α-amino functionality and a carboxylate-derived OPfp ester, with the OPfp group providing a fluorinated leaving group environment while the backbone retains the α-carboxyl functionality as an esterified derivative. In synthesis, this structure is employed as a coupling reagent or building block for stepwise peptide assembly and for preparing peptide and amino acid conjugates where an activated carboxylate handle is required for amide bond formation under controlled conditions.
CAT No: CP26252
CAS No:121593-77-9
Synonyms/Alias:Fmoc-Nle-OPfp;121593-77-9;Fmoc-L-norleucinepentafluorophenylester;(S)-Perfluorophenyl2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)hexanoate;SCHEMBL8078352;47473_FLUKA;Fmoc-L-2-aminohexanoicacid-OPfp;ZINC60272805;AKOS022174932;AK142167;FT-0642970
Fmoc-Nle-OPfp is an N-Fmoc protected norleucine derivative bearing an OPfp ester, where the Fmoc group masks the α-amino functionality and the OPfp moiety activates the carboxylate for subsequent acyl transfer. The molecule contains a single stereogenic center at the norleucine α-carbon, with the side chain presenting a linear aliphatic chain that supports incorporation into peptide sequences and peptidomimetic scaffolds. The OPfp leaving group (pentafluorophenyl ester) imparts strong electrophilicity at the carbonyl and enables controlled conversion to amide and related acylated products under peptide-synthesis-compatible conditions. The combination of a base-labile Fmoc protecting group and an acyl-activated OPfp ester makes Fmoc-Nle-OPfp a chiral amino acid intermediate tailored for downstream peptide coupling and functional derivatization.
1. Peptide Synthesis
Fmoc-Nle-OPfp is applied in peptide building block preparation for solid-phase and solution-phase peptide synthesis workflows where orthogonal reactivity is required. The Fmoc group provides an N-protected amino acid format that can be deprotected on demand, while the OPfp ester activates the carboxyl group for rapid formation of the corresponding amide bond with an incoming amine nucleophile. The norleucine side chain contributes a hydrophobic, methylene-rich segment that can be used to tune local conformational preferences and improve sequence mimicry in peptide analogs. The activated ester functionality supports efficient coupling strategies that generate peptide bonds while preserving the stereochemical integrity of the α-carbon. Fmoc-Nle-OPfp thus functions as a chemically defined intermediate for constructing peptide chains and related acylated products in applied peptide chemistry.
2. Side-Chain Functionalization
Fmoc-Nle-OPfp can be used for amino acid derivatization and side-chain functionalization strategies where OPfp ester electrophilicity enables targeted acylation of amine-containing partners. The linear norleucine side chain provides a hydrophobic handle that can be retained during synthesis, while the OPfp ester can undergo acyl transfer to introduce amide-linked motifs such as linker arms, bioconjugation handles, or analytical tags. The Fmoc-protected nitrogen supports orthogonal processing, allowing sequential deprotection and acylation steps that maintain compatibility with peptide assembly logic. The stereogenic α-center remains embedded in the resulting amide products, enabling stereochemically consistent downstream transformations. Fmoc-Nle-OPfp therefore serves as a practical reagent for constructing functionalized amino acid derivatives and acylated intermediates used in synthetic organic chemistry.
3. Bioconjugation Chemistry
Fmoc-Nle-OPfp is suitable for bioconjugation chemistry workflows that require controlled acylation using an activated carboxylate electrophile. The OPfp ester can participate in acyl transfer to generate stable amide linkages with primary amines present on biomolecule scaffolds, peptides, or linker-bearing substrates, while the pentafluorophenyl leaving group facilitates reactivity under mild, peptide-compatible conditions. The Fmoc group enables temporary masking of the amino functionality, supporting staged conjugation designs where peptide-like fragments are assembled or modified before final unmasking. The norleucine-derived hydrophobic segment can influence solubility and local microenvironment around the conjugation site, which may be relevant for preparing conjugates for biochemical assays and material-bound peptide constructs. Fmoc-Nle-OPfp thus supports the synthesis of acyl-linked conjugates and conjugation-ready amino acid fragments used in biochemical research and applied molecular engineering.
4. Protected Amino Acid Chemistry
Fmoc-Nle-OPfp is employed as a protected amino acid derivative in synthetic intermediate preparation where orthogonal protection and activated ester chemistry are required. The Fmoc group provides a base-labile N-protection strategy that integrates directly with Fmoc-based peptide synthesis and allows predictable deprotection behavior during sequence assembly. The OPfp ester functions as an acyl-activation handle that can be converted into amide derivatives without introducing additional protecting groups at the carboxyl level, supporting streamlined route design for fine chemical synthesis. The chiral norleucine backbone ensures that stereochemical information is carried through into coupled products, which is important for stereodefined peptide analogs and chiral molecular libraries. Fmoc-Nle-OPfp therefore serves as a chiral, peptide-compatible intermediate for manufacturing planning and for preparing defined amino acid derivatives used in downstream synthetic campaigns.
5. Process Chemistry Intermediate
Fmoc-Nle-OPfp is relevant to process chemistry and specialty chemical production as a defined, isolable intermediate that combines N-protection with an activated ester for controlled downstream coupling. The OPfp ester can be leveraged to design manufacturing routes that minimize coupling reagent complexity by using the electrophilicity of the pentafluorophenyl ester to drive amide formation with selected amine partners. The Fmoc group supports batchwise handling and staged processing, enabling deprotection and coupling steps that align with common Fmoc-based manufacturing logic for peptide building blocks. The linear norleucine side chain reduces steric complications relative to more hindered amino acids, which can facilitate reproducible coupling behavior in scaled synthesis of peptide fragments and acylated intermediates. Fmoc-Nle-OPfp thus functions as a chiral amino acid intermediate for industrially oriented synthesis of peptide-related materials and functional acylated compounds.
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