H-DL-Tyr-OMe · HCl

H-DL-Tyr-OMe · HCl is a hydrochloride salt of the methyl ester of tyrosine in the DL (racemic) form, featuring a phenolic side chain and an α-amino ester motif. The aromatic phenol enables selective derivatization via electrophilic aromatic substitution, O-alkylation, or protection/deprotection strategies that preserve the ring for later functionalization. The methyl ester and amino hydrochloride form a protected-like handle for coupling chemistry, while the racemic stereochemical mixture supports method development and intermediate screening where enantiopure material is not required. The salt form improves handling and can support downstream conversion to carboxylic acid derivatives, peptide building blocks, and chiral or achiral analogs in synthetic organic chemistry and biochemical research workflows.

1. Protected Amino Ester Synthesis

H-DL-Tyr-OMe · HCl serves as a practical amino acid ester intermediate for protected amino acid synthesis and peptide coupling chemistry development. The methyl ester functionality participates in activation-to-amide formation strategies, while the phenolic side chain can be protected (e.g., as an ether or carbonate) to control regioselective reactivity during peptide bond construction. The amino group present as a hydrochloride salt can be managed through base-mediated neutralization to enable coupling-compatible forms without premature side-chain modification. Downstream conversion to the corresponding activated acid or to orthogonally protected tyrosine derivatives can support library generation and process chemistry intermediate preparation.

2. Peptide Synthesis Building Block

H-DL-Tyr-OMe · HCl is suitable for peptide building block preparation in research settings where tyrosine-containing sequences or tyrosine analogs are assembled. The tyrosine backbone provides the α-amino and ester-derived carboxyl functionality necessary for iterative peptide coupling, while the phenolic side chain can be selectively protected to prevent undesired O-acylation or crosslinking during amide formation. Racemic stereochemistry can be applied to method screening, coupling-condition optimization, or the synthesis of non-stereospecific peptide fragments for analytical studies. Resulting tyrosine-bearing intermediates can be extended into protected peptide segments, enabling downstream deprotection and side-chain functional transformations.

3. Side-Chain Functionalization

H-DL-Tyr-OMe · HCl supports side-chain functionalization workflows that leverage the phenolic hydroxyl for controlled derivatization. Phenolic reactivity enables O-alkylation, O-acylation, or conversion to protected phenol forms that can endure peptide coupling and subsequent deprotection steps. The ester and amino salt framework can be carried through multi-step synthesis as a stable handle for preparing tyrosine-based conjugation motifs, including linkers for biomolecule labeling or tag incorporation. Downstream formation of phenol-functional tyrosine derivatives can feed into peptidomimetic construction and chemical biology reagent development.

4. Chemical Biology Labeling

H-DL-Tyr-OMe · HCl can be applied to chemical biology labeling strategies that require tyrosine-derived motifs with controlled phenolic chemistry. The phenolic group enables attachment-point design for conjugation reagents, including strategies that install electrophiles or reactive handles onto the aromatic ring while maintaining the amino acid core for subsequent coupling. The methyl ester and amino hydrochloride form can be converted into coupling-ready derivatives for incorporation into peptides, linkers, or affinity tags used in biomolecule modification studies. Racemic material may be used for assay development, reagent screening, or analytical standard preparation where stereochemical purity is not the limiting factor.

5. Process Chemistry Intermediate

H-DL-Tyr-OMe · HCl is relevant to process chemistry intermediate preparation for tyrosine-based fine chemical synthesis routes. The salt form and ester functionality support practical handling and can be used as a staging compound for converting to carboxylic acid derivatives, activated intermediates, or orthogonally protected tyrosine building blocks under manufacturing-compatible protection/deprotection logic. Phenolic side-chain management through protection strategies helps reduce side reactions during scale-up, particularly during coupling or activation steps that target the amino acid backbone. The compound's role as a chiral or achiral precursor can be aligned with downstream synthesis of peptide fragments, peptidomimetics, and other tyrosine-containing industrial intermediates.

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