Boc-L-Tyr(Bzl)-OSu

Boc-L-Tyr(Bzl)-OSu is a Boc-protected L-tyrosine derivative bearing a benzyl-protected phenolic side chain and an N-hydroxysuccinimide (OSu) ester at the carboxyl position. This activated amino acid ester is designed for efficient coupling in peptide and bioconjugation workflows where tyrosine side-chain protection and carboxyl activation are both required to control reactivity. The combination of Boc on the amino group and Bzl on the phenol supports selective downstream transformations in complex synthesis sequences.

1. Peptide Coupling Building Block

Boc-L-Tyr(Bzl)-OSu is widely used as an activated tyrosine building block for constructing peptides in solution-phase workflows and in custom peptide manufacturing where controlled amide bond formation is required. The OSu ester activates the carboxyl group toward nucleophilic attack by an incoming amine, enabling efficient coupling while maintaining the protected phenolic side chain (Bzl) to prevent side reactions during assembly. Researchers building tyrosine-containing peptide segments rely on the orthogonal protection pattern to preserve the aromatic phenol functionality until the appropriate deprotection stage, supporting consistent synthesis of peptides with defined Tyr residues and minimized phenolic cross-reactivity.

2. Protected Tyrosine Intermediate Synthesis

Boc-L-Tyr(Bzl)-OSu serves as a practical intermediate for preparing protected tyrosine derivatives and for generating defined Tyr-containing fragments used in segment condensation and complex peptide assembly. The Boc group on the amino functionality and the benzyl protection on the phenol provide stability under typical coupling and purification conditions, allowing chemists to carry the activated OSu functionality through intermediate steps without premature side reactions. Pharmaceutical intermediate developers and peptide chemistry teams use this activated form when they need a reliable, pre-activated tyrosine unit that integrates cleanly into downstream coupling strategies for longer sequences and multi-step synthesis campaigns.

3. Bioconjugation Coupling Reagent

Boc-L-Tyr(Bzl)-OSu is also used as a coupling reagent to attach a protected tyrosine moiety to amine-containing targets in chemical biology and materials-oriented conjugation workflows. The OSu ester provides a convenient activation mode for forming amide linkages under conditions compatible with protected amino acid handling, while the Bzl-protected phenol helps maintain side-chain integrity during the conjugation step. This makes the reagent useful for preparing tyrosine-functionalized conjugates, such as protected Tyr residues incorporated into peptide-like linkers, affinity reagents, or synthetic constructs where controlled deprotection timing is important for subsequent functionalization.

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