Fmoc-4-Bromo-L-Phenylalanine is an Fmoc-protected amino acid derivative in which the side chain of L-phenylalanine bears a para-bromo substituent on the aromatic ring. The molecule contains an Fmoc carbamate protecting group on the α-amino functionality while the carboxyl group remains available for coupling, and the stereocenter is specified as L at the α-carbon. In peptide synthesis workflows, this protected bromo-substituted aromatic amino acid is used as a building block to introduce a halogenated phenylalanine residue for structure-activity studies, chemical labeling or conjugation handle installation, and subsequent diversification of the aryl bromide.
CAT No: CP11206
CAS No:198561-04-5
Synonyms/Alias:198561-04-5;(S)-N-Fmoc-4-bromophenylalanine;Fmoc-L-4-Bromophenylalanine;FMOC-PHE(4-BR)-OH;Fmoc-4-bromo-L-phenylalanine;FMOC-L-4-BROMOPHE;Fmoc-L-phe(4-Br)-OH;FMOC-P-BROMO-PHE-OH;FMOC-L-4-BR-PHE-OH;(S)-2-((((9H-Fluoren-9-yl)methoxy)carbonyl)amino)-3-(4-bromophenyl)propanoicacid;Fmoc-D-4-Bromophenylalanine;N-(9-FLUORENYLMETHOXYCARBONYL)-4-BROMOPHENYL-L-ALANINE;(S)-N-(9-FLUORENYLMETHOXYCARBONYL)-(4-BROMOPHENYL)ALANINE;(2S)-3-(4-bromophenyl)-2-(9H-fluoren-9-ylmethoxycarbonylamino)propanoicacid;(2S)-3-(4-bromophenyl)-2-{[(9H-fluoren-9-ylmethoxy)carbonyl]amino}propanoicacid;4-Bromo-L-phenylalanine,N-FMOCprotected;PubChem23291;FMOC-PBR-L-PHE-OH;AC1MC15X;KSC185K3R;MLS001074424;SCHEMBL119803;FMOC-4'-BROMO-L-PHE;FMOC-P-BROMO-L-PHE-OH;CHEMBL1411271
Fmoc-4-Bromo-L-Phenylalanine is an Fmoc-protected L-phenylalanine derivative in which the aromatic side chain bears a para-bromo substituent, providing a defined stereogenic center at the alpha carbon and a stable N-(9H-fluoren-9-ylmethoxycarbonyl) protecting group for peptide chemistry. The combination of the Fmoc carbamate, the free carboxyl functionality (or carboxyl equivalent depending on the supplied form), and the aryl bromide enables orthogonal reactivity: peptide coupling compatibility through the protected amino group and subsequent electrophilic aromatic substitution or cross-coupling transformations through the C-Br handle. The para-bromophenyl motif increases chemical handle density on the side chain while retaining the aromatic geometry typical of phenylalanine-based scaffolds used in structure-guided peptide design. The resulting chiral amino acid intermediate can serve as a programmable building block for incorporating halogenated aromatic features into peptides, peptidomimetics, and downstream synthetic intermediates.
1. Peptide Synthesis
Fmoc-4-Bromo-L-Phenylalanine is used in peptide synthesis workflows where the Fmoc-protected amine supports standard solid-phase or solution-phase coupling strategies while maintaining the L-configuration at the alpha stereocenter. The phenylalanine backbone provides the canonical N- and C-functional groups for chain elongation, and the para-bromo substituent functions as a post-assembly derivatization handle without interfering with routine amide bond formation. Fmoc deprotection and subsequent coupling can incorporate the halogenated aromatic side chain into peptide sequences to tune hydrophobicity, aromatic packing, and chemical reactivity for later modification. Halogenated peptide products derived from this building block can be further transformed into aryl-substituted analogs or used to generate libraries for peptide-scaffold optimization in synthetic peptide chemistry.
2. Side-Chain Functionalization
Fmoc-4-Bromo-L-Phenylalanine is applied in synthetic organic chemistry and medicinal chemistry intermediate preparation where the aryl bromide enables cross-coupling and electrophile-driven functional group installation on the side chain. The para-bromo group can participate in Suzuki, Buchwald-Hartwig, or related coupling chemistries to introduce boronic-acid, alkyl, heteroaryl, or amine substituents while preserving the peptide-derived stereochemical information. The Fmoc-protected amino acid form allows the compound to be handled as a chiral, protected building block during synthesis, then converted into either free amino acid derivatives or incorporated into peptides before or after side-chain elaboration depending on the chosen protection and deprotection sequence. Downstream products include aryl-functionalized amino acid derivatives, peptidomimetics, and diversified aromatic scaffolds suitable for iterative structure-activity relationship studies and chemical library generation.
3. Chemical Biology Labeling
Fmoc-4-Bromo-L-Phenylalanine is suitable for chemical biology research and biomolecule modification strategies that require a defined aromatic motif bearing a reactive aryl halide for later conjugation. The compound's phenylalanine core supports incorporation into peptides or protein fragments, while the para-bromo substituent can serve as a handle for subsequent coupling to introduce linkers, affinity tags, or reporter-bearing substituents. Fmoc protection provides a controlled means to assemble labeled peptides with minimal side reactions during synthesis, and the stereochemically defined L-amino acid center helps preserve recognition features typical of phenylalanine-containing sequences. Labeled peptide conjugates generated from this building block can be used as probes for binding studies, receptor-ligand mapping, and mechanistic investigations where side-chain aromatic chemistry and controlled derivatization are required.
4. Peptidomimetics And SAR Studies
Fmoc-4-Bromo-L-Phenylalanine is used in peptidomimetic construction and structure-activity relationship studies where halogenated aromatic residues help modulate conformational preferences and intermolecular interactions. The Fmoc-protected amino acid format supports stepwise assembly of peptide analogs, and the para-bromo substituent enables systematic substitution patterns to generate structure-defined analog series. The chiral L-phenylalanine backbone contributes consistent stereochemistry for comparing analogs across a SAR workflow, while the aryl bromide can be converted into multiple functional variants that probe electronic and steric effects. Resulting halogenated and aryl-substituted peptidomimetics can be advanced as chemically characterized research intermediates for SAR-driven optimization of binding motifs and scaffold properties.
5. Pharmaceutical Intermediate Preparation
Fmoc-4-Bromo-L-Phenylalanine is relevant to pharmaceutical intermediate preparation and fine chemical synthesis where protected amino acid derivatives serve as controlled inputs for manufacturing-grade peptide fragments and aryl-functionalized intermediates. The Fmoc carbamate protection strategy supports reliable handling during multi-step synthesis, and the para-bromophenyl side chain provides a defined electrophilic site for downstream coupling-based diversification into aryl-substituted intermediates. The compound's stereogenic alpha carbon and phenylalanine framework align with common peptide and peptidomimetic manufacturing routes that require stereochemical integrity across intermediates. Synthesized aryl-modified amino acid and peptide-building-block derivatives can then be used to construct larger molecules, enabling process chemistry teams to design convergent routes that incorporate aromatic substitution patterns with predictable functional group outcomes.
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