Fmoc-L-Tyr(2,6-Cl2-Bzl)-OH

Fmoc-L-Tyr(2,6-Cl2-Bzl)-OH is an Fmoc-protected L-tyrosine derivative bearing a 2,6-dichlorobenzyl ether on the phenolic oxygen, creating a sterically shielded, aryl-functionalized side chain. The molecule contains the Fmoc carbamate on the amino group and a free carboxylic acid suitable for peptide coupling, while the chiral L-configuration at the alpha carbon governs stereochemical fidelity during incorporation into peptide sequences. The 2,6-dichlorobenzyl protecting group on the phenol changes the side-chain reactivity profile from phenolic hydrogen-bonding and electrophilic aromatic substitution to a protected aromatic handle that can be selectively removed under benzyl-deprotection conditions. The resulting aromatic, halogenated side chain can participate in hydrophobic and halogen-bonding interactions in peptide or peptidomimetic contexts, while the Fmoc group provides robust orthogonal protection for solid-phase synthesis workflows.

1. Peptide Synthesis

Fmoc-L-Tyr(2,6-Cl2-Bzl)-OH is used as an Fmoc-based tyrosine building block for solid-phase peptide synthesis and solution-phase peptide assembly where controlled side-chain protection is required. The protected phenolic oxygen is masked as a 2,6-dichlorobenzyl ether, preventing undesired phenol acylation or side reactions during coupling cycles while the free carboxylic acid and Fmoc carbamate enable standard amide bond formation at the alpha-carboxylate. The L-stereocenter supports stereochemically defined incorporation into peptide backbones, and the halogenated aromatic side chain can be carried through synthesis as an interaction-modulating motif. Downstream deprotection can regenerate a tyrosine phenol for subsequent conjugation, crosslinking, or further derivatization, supporting targeted peptide analog construction for biochemical research and materials-oriented peptide design.

2. Side-Chain Functionalization

Fmoc-L-Tyr(2,6-Cl2-Bzl)-OH supports amino acid derivatization strategies that require delayed activation of the tyrosine phenol. The 2,6-dichlorobenzyl ether functions as an orthogonal protecting group that can be removed to reveal a phenolic hydroxyl for controlled O-functionalization, including ether formation, esterification, or phenol-directed coupling chemistries. The dichloro-substituted benzyl group also provides a stable, aryl-rich intermediate that can be retained during early synthetic steps to suppress phenolic reactivity and maintain chemoselectivity. The resulting phenol-unmasked product can serve as a handle for constructing tyrosine-based conjugates and for generating structured analogs in chemical biology and peptidomimetic libraries.

3. Drug Discovery SAR Studies

Fmoc-L-Tyr(2,6-Cl2-Bzl)-OH is applicable to structure-activity relationship studies where tyrosine-derived aromatic pharmacophores and halogenated interaction motifs are tuned within peptide-like scaffolds. The protected tyrosine side chain preserves the aromatic ring while the 2,6-dichlorobenzyl ether modulates polarity and steric accessibility during synthesis and early assay preparation. The ability to install this residue at defined positions enables systematic variation of hydrophobicity, halogen-bonding potential, and local conformational preferences in peptide analogs or constrained peptidomimetics. Subsequent deprotection and phenol functionalization can expand the chemical space toward electrophile-reactive or conjugatable derivatives used for SAR mapping and molecular design workflows.

4. Bioconjugation Chemistry

Fmoc-L-Tyr(2,6-Cl2-Bzl)-OH is suitable for bioconjugation-oriented peptide and protein modification schemes that require controlled presentation of a tyrosine phenolic group. The Fmoc-protected amino functionality and protected phenol allow incorporation into peptide carriers with minimized side reactions, while the dichlorobenzyl ether can be removed to generate a reactive phenol for conjugation steps such as aryl-ether formation or phenol-mediated coupling strategies. The halogenated aromatic character can also influence conjugate solubility and interaction with biomolecular targets during assay development and downstream processing. The compound thereby serves as a defined, stereochemically consistent intermediate for producing tyrosine-functionalized conjugates used in chemical biology research and applied biomolecule engineering.

5. Pharmaceutical Intermediate Preparation

Fmoc-L-Tyr(2,6-Cl2-Bzl)-OH can be employed as a process-relevant protected amino acid intermediate for manufacturing peptide building blocks used in pharmaceutical-grade synthesis campaigns. The Fmoc carbamate provides a stable N-protection strategy compatible with repetitive coupling/deprotection cycles, while the 2,6-dichlorobenzyl ether protects the phenolic oxygen to reduce impurity formation from phenol oxidation or unintended acylation. The presence of a free carboxylic acid enables conversion into activated coupling forms or direct participation in peptide coupling operations, aligning with industrial peptide manufacturing practices. The halogenated aromatic side chain can be carried through intermediate stages as a controlled structural element, supporting downstream generation of defined peptide segments and peptidomimetic intermediates for fine chemical production.

6. Analytical Research Standards

Fmoc-L-Tyr(2,6-Cl2-Bzl)-OH is useful for analytical research and method development requiring structurally defined, Fmoc-protected tyrosine derivatives. The combination of Fmoc carbamate and a dichlorobenzyl-protected phenol provides distinct chromatographic and mass spectrometric signatures that can support identification and tracking of protected amino acid impurities, coupling byproducts, and deprotection outcomes. The L-configuration and fixed side-chain protection pattern help ensure that analytical references correspond to the same stereochemical and protecting-group state encountered during peptide synthesis and purification. The compound can therefore serve as a reference material for LC-MS characterization, stability studies of protected amino acid intermediates, and quality-oriented monitoring of peptide building block preparation in research and industrial settings.

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