Acetyl-L-Phenylalanine is an acetylated derivative of the proteinogenic amino acid L-phenylalanine, featuring a phenyl side chain attached to an α-amino acid backbone. The molecule bears an acetylated amino functionality (forming an N-acetyl amide) alongside a free carboxylic acid, and its stereochemistry is specified as L at the α-carbon. As an amino acid derivative, it is used in peptide chemistry and chemical biology workflows where an N-acylated phenylalanine building block is required for controlled reactivity, as well as in analytical and labeling contexts that benefit from the altered polarity and reduced basicity of the protected amino group.
CAT No: CP01605
CAS No:2018-61-3
Synonyms/Alias:N-Acetyl-L-phenylalanine;2018-61-3;Acetyl-L-phenylalanine;Ac-Phe-OH;acetylphenylalanine;L-N-Acetylphenylalanine;(S)-2-Acetamido-3-phenylpropanoicacid;N-Acetyl-l-phenalanine;N-Acetyl-3-phenyl-L-alanine;(2S)-2-acetamido-3-phenylpropanoicacid;CHEBI:16259;CBQJSKKFNMDLON-JTQLQIEISA-N;MFCD00063158;NSC45699;SBB028538;(2S)-2-(acetylamino)-3-phenylpropanoicacid;Phenylalanine,N-acetyl-;Alanine,N-acetyl-3-phenyl-,L-;PubChem6389;N-AcetylPhenylalanine;N-Acetyl-Phenylalanine;AC1L2MRM;AC1Q5QPR;N-AcetylL-phenylalanine;Maybridge1_002391
Acetyl-L-Phenylalanine is an N-acetylated derivative of L-phenylalanine featuring a phenyl side chain and an amide-capped amino terminus, which reduces the availability of the free α-amino group while preserving the carboxyl functionality for downstream chemical handling. This protected, non-zwitterionic form is commonly used as a stable, well-defined amino acid building block and analytical reference in peptide-related workflows where an N-acetylated residue or end-capped phenylalanine unit is required. Because the molecule is structurally simple and stereochemically defined at the α-carbon, it is also frequently selected for method development and standard preparation in analytical chemistry and chemical biology contexts.
1. N-Acetylated Residue Standards
Acetyl-L-Phenylalanine is widely used as a reference material for peptide and amino acid analytical workflows that require an N-acetylated phenylalanine unit. Researchers in peptide chemistry and analytical method development use it to verify retention behavior, fragmentation patterns, and derivatization outcomes when characterizing N-terminally acetylated peptides, end-capped fragments, or digestion products by LC-MS or related platforms. The N-acetyl group provides a reproducible chemical identity distinct from free L-phenylalanine, making it particularly useful for distinguishing N-acetylated species during quantitative or qualitative analyses.
2. Peptide Fragment Building Block
Acetyl-L-Phenylalanine serves as a practical building block for preparing peptide fragments and small molecules where an N-acetylated phenylalanine motif is required. Custom peptide synthesis groups and medicinal chemistry teams incorporate this residue form to generate defined termini or to model N-terminal acetylation patterns in structure-activity studies and chemical biology probes. In these workflows, the capped α-amino functionality helps control chemoselectivity and reduces side reactions associated with unprotected amino groups, while the phenyl side chain maintains the steric and hydrophobic characteristics typical of phenylalanine-containing sequences.
3. Derivatization and Calibration Reagent
Acetyl-L-Phenylalanine is commonly selected as a derivatization substrate and calibration component when developing analytical procedures for amino acid derivatives rather than free amino acids. Analytical chemistry laboratories use it to evaluate derivatization efficiency, assess recovery and matrix effects, and support method qualification for assays that target N-acetylated amino acid species. Its defined structure and N-acetylated nitrogen state make it a useful counterpart to free amino acids in comparative studies, helping confirm that the analytical method responds appropriately to amide-capped forms encountered in peptide degradation, sample cleanup, or synthetic intermediate libraries.
4. Pharmaceutical Intermediate Reference
Acetyl-L-Phenylalanine is also used as a defined intermediate reference in pharmaceutical intermediate development and specialty chemical manufacturing contexts. Process development and quality-focused R&D teams rely on such N-acetylated amino acid derivatives to support characterization of reaction mixtures, to benchmark analytical methods for amide-capped amino acid species, and to prepare defined standards for impurity profiling. The stable, non-labile N-acetyl cap and stereochemical definition at the α-carbon make it a reliable structural reference when tracking phenylalanine-derived intermediates through multi-step synthesis and purification workflows.
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