4-Chloro-DL-Phenylalanine contains an α-amino and α-carboxyl functional group on a phenylalanine backbone bearing a para-chloro substituent on the aromatic ring, classifying it as a halogenated phenylalanine derivative rather than an unmodified natural amino acid. The molecule is specified as DL, indicating a racemic mixture of stereoisomers at the α-carbon, and its side-chain aromatic ring provides a chlorinated phenyl group that can participate in hydrophobic and halogen-bonding interactions while remaining chemically compatible with standard amino acid handling as a free amino acid. In research and synthesis, it is used as a building block for preparing modified peptides and for structure-activity or binding studies where aromatic halogen substitution is used to tune physicochemical properties, as well as for analytical method development involving derivatized or labeled amino acid standards.
CAT No: CP11603
CAS No:7424-00-2
Synonyms/Alias:Fenclonine;4-Chloro-DL-phenylalanine;7424-00-2;p-chlorophenylalanine;2-amino-3-(4-chlorophenyl)propanoicacid;DL-p-Chlorophenylalanine;4-Chlorophenylalanine;Fenchlonine;Fenclonin;DL-4-Chlorophenylalanine;Phenylalanine,4-chloro-;DL-PCPA;p-Chloro-DL-phenylalanine;C-Pal;2-Amino-3-(4-chlorophenyl)propionicacid;DL-3-(p-Chlorophenyl)alanine;para-Chlorophenylalanine;p-Clorophenylalanine;DL-Phenylalanine,4-chloro-;CP10,188;Fencloninum[INN-Latin];4-Chloro-3-phenylalanine;NSC77370;Fenclonina[INN-Spanish];Alanine,3-(4-chlorophenyl)-,DL-
4-Chloro-DL-Phenylalanine is a chlorinated phenylalanine derivative supplied as a DL mixture, combining both D- and L- stereoisomers for research and synthetic workflows. The side chain retains the aromatic phenylalanine framework while introducing a para-chloro substituent, which increases chemical handle density for downstream derivatization and structure-activity studies. This amino acid is frequently used as a building block in medicinal chemistry and as a defined, halogenated amino-acid precursor for preparing analogs used in peptide and peptidomimetic development.
1. Medicinal Chemistry Analog Building
4-Chloro-DL-Phenylalanine is widely used by medicinal chemistry groups to construct halogenated amino-acid analogs for structure-activity relationship (SAR) studies and binding-site mapping campaigns. The para-chloro substituent provides a robust site for further functionalization (for example, electrophile/metal-mediated transformations or derivatization into aryl-substituted motifs) while maintaining the amino-acid backbone needed for incorporation into larger scaffolds. In practice, researchers select this DL form when they want a defined chlorinated phenylalanine precursor without committing to a single stereochemistry during early-stage analog screening, library synthesis, or comparative SAR work.
2. Peptidomimetic And Peptide Analog Synthesis
4-Chloro-DL-Phenylalanine serves as a practical building block for preparing peptide analogs and peptidomimetic structures where an aromatic, para-chloro substituted side chain is required to probe conformational preferences, hydrophobic contacts, or aromatic interaction patterns. Chemical biology and peptide development teams commonly use halogenated amino-acid derivatives like this one to generate series of analogs for downstream evaluation in biochemical assays and assay development workflows. The presence of the amino-acid functionality enables integration into protected intermediate routes and subsequent assembly into larger peptide-like constructs, supporting systematic variation of side-chain electronics and steric profile.
3. Pharmaceutical Intermediate Development
4-Chloro-DL-Phenylalanine is also used as a defined intermediate in the synthesis of more complex, halogenated aromatic fragments and amino-acid-derived intermediates for pharmaceutical research programs. Process and development chemists value this reagent for its clear compositional definition (chlorinated phenylalanine) and for serving as a convenient starting point toward substituted aromatic motifs that appear in many medicinal chemistry lead series. The DL stereochemical mixture is often leveraged at the intermediate stage when the goal is efficient generation of downstream derivatives prior to any later stereochemical resolution or stereochemically controlled diversification.
4. Analytical Reference And Method Development
4-Chloro-DL-Phenylalanine is frequently employed as an analytical reference material during method development and characterization of amino-acid-containing intermediates, especially in workflows that require a structurally specific, halogenated phenylalanine standard. Analytical chemistry teams use it to support LC-MS or related characterization strategies for confirming identity, monitoring derivatization steps, and validating the presence of chlorinated amino-acid motifs in complex reaction mixtures. The defined chlorinated aromatic structure provides a strong, easily distinguishable feature compared with non-halogenated amino-acid analogs, which helps streamline troubleshooting and documentation in synthetic and analytical development.
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