L-Phenylalanine benzyl ester tosylate is a phenylalanine-derived amino acid ester in which the carboxyl group is converted to a benzyl ester and the amino functionality is present as a tosylate-protected form. The molecule therefore contains an ester carbonyl linked to a benzyl group while the side chain retains the benzyl-like hydrophobic phenyl ring characteristic of phenylalanine, and the tosylate group provides an additional sulfonate-based protection that suppresses free amine reactivity during handling and coupling. In peptide and amino acid derivative synthesis, this protected ester is used as a precursor that can be deprotected or transformed to control chemoselectivity and to support stepwise assembly or further functionalization for analytical method development and structure-activity studies.
CAT No: CP01633
CAS No:1738-78-9
Synonyms/Alias:1738-78-9;L-phenylalaninebenzylesterp-toluenesulfonate;(S)-Benzyl2-amino-3-phenylpropanoate4-methylbenzenesulfonate;H-PHE-OBZLP-TOSYLATE;3-phenyl-l-alaninebenzylester4-toluenesulphonate;H-Phe-OBzlTos;H-Phe-OBzl.Tos;SCHEMBL718199;962-39-0(Parent);CTK0I2990;MolPort-003-983-033;ZLZGBBIPWXUQST-RSAXXLAASA-N;ACT07363;EINECS217-096-7;L-Phenylalaninebenzylestertosylate;AKOS015842537;AKOS015889729;AM82164;AK-49485;KB-53353;DB-028569;TC-066755;benzylphenylalaninatep-toluenesulfonicacid;FT-0628001;ST24036266
L-Phenylalanine benzyl ester tosylate is an L-phenylalanine derivative in which the α-amino group is masked as a tosylamide and the α-carboxyl group is converted to a benzyl ester, creating a chiral amino acid ester with orthogonally protected functionality. The molecule contains a stereogenic center at the α-carbon, an aromatic side chain (benzyl-substituted phenyl group), and two protecting-group elements that modulate nucleophilicity and control chemoselective transformations. The benzyl ester can participate in C-terminal protection strategies and can be removed under hydrogenolysis conditions, while the tosyl group provides robust N-protection that survives many peptide-coupling conditions. The resulting reactivity profile supports peptide building block preparation, controlled deprotection sequences, and downstream conversion into carboxyl-activated or side-chain-functionalized intermediates for synthetic organic chemistry and biochemical research workflows.
1. Protected Amino Acid Synthesis
L-Phenylalanine benzyl ester tosylate is used in protected amino acid synthesis workflows where orthogonal N- and C-terminal protection is required for reliable intermediate handling. The tosyl-protected amide nitrogen reduces undesired side reactions during ester formation, activation, and coupling steps, while the benzyl ester stabilizes the carboxyl group against premature amide formation. The L-configuration at the α-carbon enables stereochemically defined amino acid derivatives that can be carried through multi-step sequences without racemization-sensitive exposure. The compound can be converted into activated carboxyl derivatives or deprotected selectively to furnish downstream protected amino acid building blocks for peptide construction and process chemistry intermediate preparation.
2. Peptide Coupling Chemistry
L-Phenylalanine benzyl ester tosylate supports peptide coupling chemistry as a chiral, N-protected amino acid ester that aligns with standard amide bond formation strategies. The tosylamide functionality provides a controlled nitrogen state for chemoselective activation of the carboxyl component, while the benzyl ester serves as a protected C-terminus that can be transformed into coupling-ready species. The aromatic side chain of phenylalanine participates as a nonpolar recognition element in peptide sequences and can influence solubility and aggregation behavior during peptide synthesis and purification. The protected amino acid derivative can be incorporated into peptide building block preparation, enabling stepwise assembly of oligopeptides and peptide analogs with defined stereochemistry and protected-group compatibility.
3. Peptidomimetic And SAR Studies
L-Phenylalanine benzyl ester tosylate is applicable to peptidomimetic construction and structure-activity relationship studies where controlled functional group manipulation of an L-phenylalanine scaffold is required. The protected amine and ester groups allow sequential derivatization, including conversion of the C-terminal functionality into amide-linked analogs and preparation of intermediates for side-chain modifications that tune hydrophobicity and conformational preferences. The benzyl ester can function as a handle for generating C-terminal variants, while the tosyl protection can be retained during scaffold elaboration to maintain chemoselectivity. The resulting derivatives can be used to generate focused libraries of amino acid-based analogs for SAR investigations and molecular design campaigns that rely on stereochemically consistent building blocks.
4. Chemical Biology And Bioconjugation
L-Phenylalanine benzyl ester tosylate can be employed in chemical biology workflows that require amino acid-derived linkers and conjugation-ready intermediates with controlled functional group reactivity. The tosyl-protected nitrogen and benzyl ester enable stepwise preparation of conjugation handles by allowing selective deprotection and subsequent installation of reactive moieties at the termini. The phenylalanine aromatic side chain supports hydrophobic interactions and can be used to modulate local microenvironment in tagged peptides, affinity probes, or labeling reagents. The compound's protected-state chemistry supports formation of well-defined conjugates and biochemical research intermediates that integrate into labeling strategies and biomolecule modification pipelines.
5. Pharmaceutical Intermediate Preparation
L-Phenylalanine benzyl ester tosylate is suitable for pharmaceutical intermediate preparation where protected amino acid derivatives are required for manufacturing-grade synthetic routes. The orthogonal protection pattern supports controlled conversion into peptide-like intermediates, including formation of amide bonds and subsequent deprotection to reveal functional termini for downstream elaboration. The benzyl ester can be used as a C-terminal protecting group element in synthetic sequences that require hydrogenolysis-compatible deprotection steps, while the tosyl group provides stability during coupling and intermediate purification operations. The compound can therefore serve as a chiral amino acid intermediate for fine chemical synthesis and industrial manufacturing of amino acid-containing intermediates used in active ingredient or process-related synthesis.
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