L-Phenylalanine amide hydrochloride is an L-phenylalanine derivative in which the carboxyl group is converted to a primary amide and the resulting amide functionality is present as a hydrochloride salt. The molecule retains the amino group and the benzyl side chain characteristic of phenylalanine, with the salt form associated with the protonated amine to increase ionic character and control solubility. It is used as a chemically defined amino acid amide building block for peptide and peptidomimetic synthesis, for preparing amide-linked analogues in structure-activity studies, and for analytical method development where a phenylalanine-based amide substrate or reference standard is required.
CAT No: CP01628
CAS No:65864-22-4
Synonyms/Alias:L-Phenylalaninamidehydrochloride;65864-22-4;H-PHE-NH2HCL;L-Phenylalanineamidehydrochloride;phenylalanineamidehydrochloride;H-Phe-NH2.HCl;C9H12N2O.HCl;H-Phe-NH2Cl;PubChem19011;(2S)-2-amino-3-phenyl-propanamideHydrochloride;P2376_SIGMA;SCHEMBL354542;CTK8B2118;KLHLGTPNBQXSJT-QRPNPIFTSA-N;MolPort-003-959-198;BB_NC-2378;(S)-phenylalaninamidehydrochloride;ANW-35108;CH-427;KM0960;AKOS015849171;AKOS015889950;AM82182;MCULE-9635114334;(2S)-2-amino-3-phenylpropionamideHCl
L-Phenylalanine amide hydrochloride is an L-configured phenylalanine-derived carboxamide salt, presenting a chiral α-amino center alongside a side-chain benzyl group and a terminal amide that is protonated under hydrochloride conditions. The amide functionality changes the reactivity profile relative to the corresponding carboxylic acid or ester, enabling stable coupling as a protected-like handle while limiting direct carboxyl activation. The hydrochloride form improves handling of the amino group for synthetic operations that require controlled nucleophilicity and salt-stabilized intermediates. The combination of stereodefined amino acid architecture and benzyl side-chain supports downstream peptide and peptidomimetic assembly, as well as intermediate preparation for medicinal chemistry and process-scale fine chemical synthesis.
1. Peptide Coupling Chemistry
L-Phenylalanine amide hydrochloride is used in peptide synthesis workflows where a phenylalanine-based building block is required with the carboxyl functionality masked as an amide. The L-configuration at the α-carbon and the benzyl side chain align with standard amino acid recognition motifs, while the terminal amide can participate as a stable end-group or be transformed into further derivatives through selective N-functionalization strategies. Salt formation as the hydrochloride can facilitate controlled amide nitrogen handling during coupling sequence design, including compatibility with common peptide coupling reagents when the amide nitrogen is intended to remain intact. The resulting derivatives can serve as peptide fragments, capping units, or peptidomimetic precursors that maintain stereochemical fidelity from the amino acid scaffold.
2. Peptidomimetics And SAR Studies
L-Phenylalanine amide hydrochloride supports medicinal chemistry programs focused on peptidomimetic construction and structure-activity relationship studies by providing a stereodefined phenylalanine motif with a non-ionizable terminal carboxamide. The amide group is well suited for mimicking peptide bond environments and for tuning hydrogen-bonding patterns in analog libraries, while the benzyl side chain enables hydrophobic and aromatic interaction modeling. Derivatization of the amide nitrogen, together with side-chain-directed modifications introduced at later stages, can generate analog series for SAR experiments without disrupting the α-chiral center. Downstream use commonly includes fragment-based scaffold elaboration and synthesis of constrained or capped peptide-like structures that preserve amino acid stereochemistry.
3. Chemical Biology Labeling
L-Phenylalanine amide hydrochloride is applicable to chemical biology research requiring amino acid-derived handles for conjugation chemistry and biomolecule modification. The amide hydrochloride provides an amino-functionalized platform that can be converted into activated intermediates for coupling to electrophilic partners, enabling attachment to probes, affinity tags, or imaging reagents while retaining the phenylalanine stereocenter. The benzyl side chain can be leveraged for hydrophobic positioning in probe design, and the carboxamide end-group can influence solubility and stability of the resulting conjugates. The compound can therefore serve as a chiral building block for constructing labeled peptide mimics, receptor-binding fragments, or enzyme-interaction probes used in biochemical interrogation.
4. Pharmaceutical Intermediate Preparation
L-Phenylalanine amide hydrochloride is utilized in pharmaceutical intermediate preparation where amino acid-derived amides are required as stable, isolable chiral intermediates for downstream synthesis. The carboxamide functionality provides a synthetic endpoint compatible with protecting-group strategies that avoid carboxyl activation steps, while the L-stereochemistry supports stereocontrolled manufacturing routes. The hydrochloride salt form can be advantageous for reproducible handling in process chemistry, particularly when the amine is needed in a defined protonation state for subsequent functional group transformations. The resulting derivatives can feed into larger synthetic sequences that generate peptidic fragments, amide-linked motifs, or chiral building blocks used in fine chemical production.
5. Analytical Standards Development
L-Phenylalanine amide hydrochloride can be employed as an analytical reference material for amino acid and peptide-related method development, including LC-MS and chromatographic quantification of phenylalanine-derived amide species. The defined stereochemistry at the α-carbon and the presence of the benzyl side chain help distinguish it from isomeric or carboxylate/ester analogs in analytical workflows. The terminal amide hydrochloride form provides a consistent ionization behavior that can support method calibration for amide-containing fragments and for monitoring derivatization steps during peptide synthesis. The compound's structure also enables use in impurity profiling and stability studies of peptide-like intermediates where carboxamide formation and nitrogen protonation states affect analytical readouts.
6. Side-Chain Functionalization Routes
L-Phenylalanine amide hydrochloride is suitable for synthetic organic chemistry routes that introduce functionality onto the phenylalanine side chain while maintaining the carboxamide end-group. The benzyl aromatic moiety can be used as a platform for electrophilic substitution, oxidative transformations, or subsequent coupling to heteroatom-containing substituents, enabling generation of substituted phenylalanine amide analogs. The stereodefined α-amino center and the amide nitrogen support selective protection and deprotection logic, allowing orthogonal functional group management during multistep synthesis. Downstream, the resulting side-chain-functionalized derivatives can serve as intermediates for peptidomimetic scaffolds, receptor-binding fragments, or process-scale fine chemical intermediates where controlled aromatic substitution patterns are required.
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