4-Cyano-D-Phenylalanine is a non-proteinogenic, aromatic amino acid derivative featuring a phenylalanine backbone with a cyano substituent at the para position of the benzyl side chain and a D-stereochemical configuration at the α-carbon. The molecule contains a free amino group and a free carboxyl group, and the nitrile side chain provides a strongly electron-withdrawing functional handle that can influence hydrogen-bonding patterns and side-chain polarity in peptide contexts. In synthetic and chemical biology workflows, it is used as a defined building block for preparing modified peptides and structure-activity or binding studies where the para-cyano aromatic functionality and D-configuration are used to probe structure effects and labeling or conjugation strategies.
CAT No: CP11902
CAS No:263396-44-7
Synonyms/Alias:263396-44-7;(R)-2-Amino-3-(4-cyanophenyl)propanoicacid;4-Cyano-D-Phenylalanine;D-4-Cyanophenylalanine;(2R)-2-amino-3-(4-cyanophenyl)propanoicacid;H-D-Phe(4-CN)-OH;D-4-Cyanophe;AmbotzHAA7570;PubChem13160;PubChem18610;AC1LT3NC;L-4-CN-Phe-OH;(D)-4-Cyanophenylalanine;SCHEMBL838534;CTK8E9381;MolPort-000-002-485;ZINC4240191;MFCD00270364;AM82774;AN-8486;CS14056;AJ-49254;AK117406;KB-38390;SC-10585
4-Cyano-D-Phenylalanine is a D-configured phenylalanine analog bearing a nitrile (cyano) substituent on the aromatic ring, making it a non-proteinogenic amino acid building block for structure-property studies and chemically defined peptide or peptidomimetic synthesis. The rigid, electron-withdrawing nitrile functionality provides a handle for medicinal chemistry profiling, conformational and electronic effects, and downstream analytical characterization when incorporated into larger molecules. Its stereochemistry and side-chain substitution pattern make it particularly useful when researchers need a defined non-natural residue rather than a native phenylalanine counterpart.
1. Peptidomimetic Building Blocks
4-Cyano-D-Phenylalanine is used by medicinal chemistry and peptide engineering groups to introduce a defined D-amino acid residue into peptidomimetics and non-natural peptide analogs. The ring nitrile provides a strong electronic perturbation relative to unsubstituted phenylalanine, supporting SAR (structure-activity relationship) workflows where researchers compare how side-chain electronics influence binding interactions, conformational preferences, and overall molecular behavior. Incorporation into short peptide scaffolds or larger peptidomimetic constructs is also a common strategy for generating chemically well-defined standards for downstream characterization by LC-MS and related analytical methods.
2. Protein Engineering Probes
4-Cyano-D-Phenylalanine is selected in chemical protein engineering and protein labeling workflows that require site-specific incorporation of a non-natural, stereodefined aromatic residue. Researchers use D-configured, cyano-substituted amino acid building blocks to create proteins or protein fragments with a distinct chemical signature that can be tracked analytically or used to probe structure-function relationships in controlled systems. The nitrile group can serve as a chemically distinctive substituent for orthogonal characterization approaches, enabling comparisons between constructs that differ only in side-chain substitution while maintaining the same backbone stereochemistry.
3. Analytical Reference Standards
4-Cyano-D-Phenylalanine is frequently used to prepare analytical reference materials for method development and validation in LC-MS workflows targeting non-natural amino acids, modified peptides, or degradation/processing products. The cyano-substituted aromatic side chain provides a unique mass/fragmentation pattern that helps distinguish it from native phenylalanine and other aromatic analogs during quantitation or identification. Analytical laboratories and contract research organizations use this compound to benchmark retention behavior, confirm peak assignments, and support identification criteria in complex sample matrices such as peptide mixtures or reaction monitoring samples.
4. Pharmaceutical Intermediate Development
4-Cyano-D-Phenylalanine is employed as a specialized chiral amino acid intermediate for downstream synthesis of cyano-substituted peptidomimetic fragments and related medicinal chemistry building blocks. The combination of D-stereochemistry and aromatic nitrile functionality makes it a practical starting point when developers need a defined stereochemical scaffold and an electron-withdrawing substituent for iterative analog generation. In industrial and R&D settings, this compound supports the preparation of defined intermediates used in library synthesis, SAR campaigns, and the production of non-natural peptide components where side-chain identity must be tightly controlled.
1. SERS spectrum of the peptide thymosin‐β4 obtained with Ag nanorod substrate
3. Cell-based adhesion assays for isolation of snake venom’s integrin antagonists
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