L-Phenylalanine ethyl ester hydrochloride is an amino acid ester derivative of L-phenylalanine in which the carboxyl group is converted to an ethyl ester while the amino functionality is present as a hydrochloride salt. The molecule retains the phenyl side chain characteristic of phenylalanine, and the esterification changes the carboxyl reactivity relative to the free amino acid by masking the carboxyl group as an ethyl ester. As a protected carboxyl form and salt-stabilized amino ester, it is used in peptide-related intermediate preparation, substrate synthesis, and analytical or derivatization workflows where controlled handling of the amino and ester functionalities is required.
CAT No: CP01634
CAS No:3182-93-2
Synonyms/Alias:L-Phenylalanineethylesterhydrochloride;3182-93-2;H-Phe-OEt.HCl;EthylL-phenylalaninatehydrochloride;(S)-Ethyl2-amino-3-phenylpropanoatehydrochloride;ethyl(2S)-2-amino-3-phenylpropanoatehydrochloride;ethyll-phenylalaninatehydrochloride(1:1);L-phenylalanineethylester;PubChem19008;AC1Q3ECL;EthylL-phenylalaninateHCl;SCHEMBL216055;220701_ALDRICH;AC1L4W23;Jsp003392;Jsp005914;CTK3J4860;FPFQPLFYTKMCHN-PPHPATTJSA-N;MolPort-002-919-239;EINECS221-673-9;ANW-59148;AR-1I9781;MFCD00012507;AKOS015845150;AKOS015889880
L-Phenylalanine ethyl ester hydrochloride is the ethyl ester hydrochloride salt of L-phenylalanine, retaining the α-amino acid stereocenter in the L-configuration and presenting a benzyl side chain that supports hydrophobic and π-interaction driven recognition. The molecule combines an esterified carboxylate with a protonated amine counterbalanced by chloride, which modulates solubility and can influence coupling behavior in peptide chemistry. The aromatic phenyl ring can participate in electrophilic substitution or serve as a handle for downstream derivatization, while the ester group enables controlled conversion to amides, acids, or protected acid forms through standard functional-group interconversions. As a chiral amino acid ester intermediate, it is suited for stereochemically consistent synthesis of peptide building blocks and for preparing functionalized L-phenylalanine derivatives used in synthetic organic chemistry and biochemical research.
1. Peptide Coupling Chemistry
L-Phenylalanine ethyl ester hydrochloride is applied in peptide synthesis workflows where an amino acid ester precursor is converted into coupling-ready derivatives for amide bond formation. The L-configuration at the α-carbon, together with the benzyl side chain, supports stereochemically defined incorporation into peptide sequences and peptidomimetic scaffolds. The ethyl ester functionality can be transformed into carboxy-activated equivalents or into a protected acid form compatible with common coupling strategies, while the hydrochloride salt form helps manage amine protonation during derivatization steps. Downstream, the resulting L-phenylalanine units can be used to construct linear peptides, cyclic peptides, or protected intermediate fragments for fragment-based assembly in synthetic methodology development.
2. Chiral Amino Acid Intermediate
L-Phenylalanine ethyl ester hydrochloride functions as a chiral amino acid intermediate for stereoselective synthesis of L-phenylalanine derivatives used in fine chemical production. The protected carboxyl group as an ethyl ester provides a controllable handle for selective transformations, including ester exchange, hydrolysis to the free acid, or conversion to amide-forming intermediates. The hydrochloride salt form can facilitate reproducible handling in chiral synthesis by maintaining the amine in a defined protonation state prior to activation or protection. The benzyl side chain and preserved L-stereochemistry enable downstream formation of chiral building blocks for SAR studies, molecular design libraries, and stereodefined analog generation in applied synthetic chemistry.
3. Side-Chain Functionalization
L-Phenylalanine ethyl ester hydrochloride is suitable for side-chain modification strategies that leverage the aromatic phenyl ring of L-phenylalanine to introduce new binding motifs or reactive handles. The esterified carboxyl group can be maintained during electrophilic aromatic substitution, halogenation, or other aromatic functionalization steps, helping prevent uncontrolled reactions at the carboxyl functionality. The benzyl side chain can be further elaborated into substituted phenylalanine analogs that participate in receptor-binding studies, enzyme substrate analog design, or chemical biology probe development. Resulting functionalized amino acid derivatives can then be carried forward into peptide analog construction or used as intermediates for heteroaromatic and aromatic-rich scaffold synthesis.
4. Chemical Biology Probes
L-Phenylalanine ethyl ester hydrochloride is used in chemical biology research to generate labeled or reactive L-phenylalanine derivatives for biomolecule interaction studies. The amino acid framework provides a defined stereochemical motif for incorporation into peptide-like probes, while the ester group can be converted into amide or acid forms that support conjugation chemistry. The aromatic side chain can serve as a hydrophobic anchor in affinity probes and can be modified to tune binding interactions or introduce functional groups for subsequent coupling to targeting moieties. Downstream applications include preparation of peptide-based reporters, affinity tags, and assay-compatible intermediates that enable controlled biomolecule labeling and molecular recognition investigations.
5. Pharmaceutical Intermediate Preparation
L-Phenylalanine ethyl ester hydrochloride is relevant to pharmaceutical intermediate preparation where chiral amino acid building blocks are required for synthesis of peptide-derived or amino acid-based active scaffolds. The L-configuration and benzyl side chain support consistent stereochemical outcomes when incorporated into protected amino acid units used for stepwise assembly of complex molecules. The ethyl ester can be hydrolyzed or transformed into activated carboxyl derivatives as part of manufacturing-oriented route design, while the hydrochloride salt form supports predictable handling of the amine during conversion to protected or activated intermediates. Downstream, the compound can be employed to prepare protected amino acid derivatives, coupling partners, and stereodefined fragments used in fine chemical synthesis and specialty chemical production for research and development supply chains.
6. Analytical Standards And Method Development
L-Phenylalanine ethyl ester hydrochloride can be used to support analytical research and method development for amino acid ester and amino acid derivative profiling. The defined structure, including the L-stereocenter and aromatic side chain, enables reference standard preparation for chromatographic or spectrometric characterization of phenylalanine-related intermediates. The ester hydrochloride form helps distinguish analytes across ester/acid and salt-state transformations, supporting method validation for monitoring derivatization steps in peptide building block synthesis. Downstream use includes preparation of calibration standards and structural controls for tracking conversion to protected amino acid derivatives, enabling more reliable interpretation of synthetic progress in applied amino acid chemistry.
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