L-threo-Phenylserine

L-threo-Phenylserine is an L-configured amino acid bearing a β-hydroxyl group and a benzyl-substituted side chain, giving it a stereogenic relationship between the α-carbon and the threo-oriented β-hydroxyl substituent. The molecule contains a primary amino functionality and a carboxylic acid, which together enable salt formation, controlled protection, and standard peptide coupling chemistry after conversion to protected amino acid derivatives or activated esters. The side-chain hydroxyl supports selective derivatization to ethers or esters, while the benzylic aromatic ring can participate in hydrophobic and π-interaction-driven recognition during peptide and peptidomimetic design. As a chiral amino acid intermediate, L-threo-Phenylserine can be incorporated into protected building blocks for stereochemically defined peptide analogs and can also serve as a precursor for downstream functional transformations of the β-hydroxy group.

1. Peptide Synthesis

L-threo-Phenylserine is applied in peptide building block preparation where its amino acid backbone supports N-protection and C-carboxyl activation for amide bond formation. The threo stereochemistry around the β-hydroxyl-bearing side chain can be retained through orthogonal protection of the hydroxyl, allowing sequential coupling strategies for dipeptides and longer peptide sequences. Side-chain hydroxyl protection as an ether or ester is commonly leveraged to prevent undesired O-acylation during peptide coupling, followed by controlled deprotection to regenerate the free β-hydroxy functionality. Resulting peptide products can be used as defined substrates or analogs in biochemical research and as stereochemically constrained residues in peptidomimetic libraries.

2. Amino Acid Derivatization

L-threo-Phenylserine is suitable for amino acid derivatization workflows that target the β-hydroxyl group for functional group interconversion while maintaining the chiral center for consistent stereochemical outcomes. Hydroxyl-bearing side chains can be converted to protected esters for later release, or to ether derivatives that tune polarity and stability in synthetic sequences. The presence of the carboxylic acid and amino group enables formation of salts, activated intermediates, and protected derivatives that can undergo downstream transformations such as electrophile-mediated substitution at oxygen or incorporation into larger scaffolds. Chiral derivatives derived from L-threo-Phenylserine can serve as intermediates for fine chemical synthesis and as stereochemically defined components in structure-activity relationship studies.

3. Chemical Biology Probes

L-threo-Phenylserine is used in chemical biology research to generate stereochemically defined amino acid and peptide analogs containing a β-hydroxyl functional handle. The hydroxyl group can be exploited for conjugation chemistry after conversion to an appropriate protected intermediate, enabling attachment to linkers, affinity tags, or reporter-bearing moieties while preserving the threo stereochemical arrangement. N- and O-protection strategies support controlled deprotection to expose the reactive hydroxyl at the desired stage, which can be important for selective labeling in complex reaction environments. L-threo-Phenylserine-derived constructs can function as molecular probes, substrate mimics, or assay components for studying recognition events that depend on side-chain stereochemistry and hydrogen-bonding patterns.

4. Peptidomimetics And SAR

L-threo-Phenylserine is applied in peptidomimetic and SAR studies where the β-hydroxyl and aromatic side chain contribute to conformational preferences and interaction profiles. The stereochemically defined threo relationship can be maintained through protected amino acid synthesis, supporting consistent residue placement in analog series where small stereochemical changes alter binding or processing. Side-chain hydroxyl availability enables systematic modulation of hydrogen-bond donor/acceptor properties through ester/ether variants, while the aromatic ring supports hydrophobic and π-interaction tuning. L-threo-Phenylserine-based analogs can be incorporated into fragment-sized peptide scaffolds or longer constrained peptides to support iterative medicinal chemistry design and mechanistic investigations.

5. Pharmaceutical Intermediate Preparation

L-threo-Phenylserine is relevant to pharmaceutical intermediate preparation in process chemistry contexts where chiral amino acid building blocks are required for downstream synthesis of active pharmaceutical ingredient fragments or excipient-related structures. The amino acid functionality supports conversion into N-protected forms and, when needed, selective hydroxyl protection to control chemoselectivity during multi-step coupling or functional group installation. The carboxyl group can be transformed into activated derivatives suitable for controlled incorporation into amide linkages, while the β-hydroxyl can be held protected to avoid side reactions and later unveiled for final scaffold assembly. L-threo-Phenylserine therefore functions as a stereochemically defined chiral intermediate that can integrate into manufacturing-oriented synthetic routes for fine chemical production.

1. Investigating Potential Interactions Between Neurohypophyseal Peptides, their Drug Analogs, and Coagulation Factor VIII

2. Store-operated Ca2+ entry sustains the fertilization Ca2+ signal in pig eggs

3. Urinary Metabolites Associated with Blood Pressure on a Low-or High-Sodium Die

4. Relatedness of antibodies to peptides containing homocitrulline or citrulline in patients with rheumatoid arthritis

5. Tachykinin-related peptides modulate immune-gene expression in the mealworm beetle Tenebrio molitor L