Boc-3,4-Difluoro-L-Phenylalanine is a Boc-protected, fluorinated phenylalanine derivative in which the phenyl side chain bears two fluorine atoms at the 3- and 4-positions, retaining an L-phenylalanine backbone. The molecule contains a Boc-protected amino group and a free carboxylic acid, with the difluorinated aromatic ring providing increased electron-withdrawing character and altered hydrophobic and steric features compared with unsubstituted phenylalanine. As a protected amino acid building block, it is used in peptide synthesis to introduce a difluorinated phenylalanine residue while the Boc group helps control chemoselectivity during stepwise coupling and deprotection strategies.
CAT No: CP13004
CAS No:198474-90-7
Synonyms/Alias:198474-90-7;Boc-L-3,4-Difluorophenylalanine;boc-l-3,4-difluorophe;Boc-3,4-difluoro-L-phenylalanine;Boc-Phe(3,4-F2)-OH;boc-phe(3,4-dif)-oh;boc-3,4-difluorophenylalanine;(2s)-2-[(tert-butoxycarbonyl)amino]-3-(3,4-difluorophenyl)propanoicacid;Boc-L-phe(3,4-F2)-OH;SBB063926;N-BOC-3,4-DIFLUORO-L-PHENYLALANINE;3,4-difluoro-l-phenylalanine,bocprotected;(s)-2-(tert-butoxycarbonylamino)-3-(3,4-difluorophenyl)propanoicacid;3,4-difluoro-l-phenylalanine,n-bocprotected;N-(tert-Butoxycarbonyl)-3,4-difluoro-L-phenylalanine;n-alpha-t-butyloxycarbonyl-3,4-difluoro-l-phenylalanine;(s)-2-tert-butoxycarbonylamino-3-(3,4-difluoro-phenyl)-propionicacid;(2S)-3-(3,4-difluorophenyl)-2-[(tert-butoxy)carbonylamino]propanoicacid;(2S)-2-(tert-butoxycarbonylamino)-3-(3,4-difluorophenyl)propanoicacid;PubChem6120;AC1ODU01;Boc-Phe(3,4-F)-OH;14994_ALDRICH;SCHEMBL1516520;14994_FLUKA
Boc-3,4-Difluoro-L-Phenylalanine is a Boc-protected, stereodefined amino acid building block featuring a difluorinated phenyl side chain that introduces distinct electronic and steric properties relative to unsubstituted phenylalanine. This protected form is commonly used in peptide and peptidomimetic assembly workflows where controlled incorporation of fluorinated aromatic residues is needed for structure-activity relationship studies and conformational/electronic tuning. Researchers also leverage the difluoro substitution to probe how aryl fluorination impacts physicochemical behavior in downstream peptide analogs and medicinal chemistry leads.
1. Fluorinated Peptide Synthesis
Boc-3,4-Difluoro-L-Phenylalanine is used by peptide chemistry groups to introduce a defined 3,4-difluorinated aromatic residue into peptide sequences and peptide analogs. The Boc protection supports its role as a protected amino acid building block for controlled coupling during peptide construction, while the difluorinated phenyl ring provides a handle for medicinal chemistry programs seeking to modulate local polarity, aromatic electronics, and steric profile within a peptide scaffold. This makes it a practical choice for custom peptide synthesis and SAR-focused library preparation where site-specific incorporation of fluorinated amino acids is required.
2. Peptidomimetic And SAR Building Block
Boc-3,4-Difluoro-L-Phenylalanine is frequently selected in medicinal chemistry and peptidomimetic development to generate analog series that systematically vary aromatic substitution patterns. The 3,4-difluoro substitution on the phenyl side chain enables chemists to explore how fluorination influences intermolecular interactions and overall molecular properties of peptide-like compounds, supporting structure-activity relationship workflows. Development teams use this building block when they need a protected, stereochemically defined fluorinated residue that can be incorporated into larger intermediate frameworks en route to candidate molecules.
3. Pharmaceutical Intermediate Development
Boc-3,4-Difluoro-L-Phenylalanine is also used as a fluorinated amino acid intermediate in the preparation of more complex, fluorinated building blocks for downstream synthetic campaigns. Process and development chemists rely on the Boc-protected amino functionality to manage reactivity during multi-step synthesis, allowing incorporation of the difluorinated aromatic motif into advanced intermediates used for peptide-derived small molecules and related chemical series. This application is especially relevant when a defined fluorinated aromatic stereochemical unit must be carried through synthetic sequences with minimal ambiguity.
4. Analytical Reference For Fluorinated Residues
Boc-3,4-Difluoro-L-Phenylalanine is employed as a defined reference material in analytical method development and characterization workflows involving fluorinated amino acid residues. Laboratories use it to support LC-MS, HPLC, and related analytical verification of peptide fragments or synthetic intermediates that contain the 3,4-difluorophenylalanine motif. Having a fully specified, protected standard helps confirm identity during synthesis monitoring, fragment analysis, and impurity profiling for projects that incorporate fluorinated aromatic amino acids.
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