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| Product Name | Fmoc-Tyr(tBu)-OH |
|---|---|
| Synonyms | Fmoc-O-tert-butyl-L-tyrosine |
| Product ID | 557 |
| Catalog No. | AS0709 |
| CAS Number | 71989-38-3 |
| Molecular Formula | C28H29NO5 |
| Molecular Weight | 459.53 g/mol |
| Appearance | White to off-white powder |
| Reference Melting Point | Approximately 150–156°C |
| Side-Chain Protection | tert-Butyl-protected phenolic hydroxyl |
| Primary Application | Fmoc-SPPS |
Product Overview
Fmoc-Tyr(tBu)-OH is the conventional tBu-protected L-tyrosine derivative used in Fmoc-SPPS.
The α-amino group is protected by Fmoc, while the phenolic hydroxyl is protected with an acid-labile tert-butyl group.
This prevents unwanted acylation of the phenolic oxygen during peptide-chain elongation.
Applications in Peptide Synthesis
| Application | Role of Fmoc-Tyr(tBu)-OH |
|---|---|
| Fmoc-SPPS | Standard protected L-tyrosine building block |
| Tyr-Containing Peptides | Protects the phenolic OH during elongation |
| Aromatic Peptides | Introduces an aromatic side chain with a phenolic group |
| SAR Studies | Supports investigation of aromatic and H-bond interactions |
| Peptide Libraries | Standard proteinogenic residue |
| Modified Peptides | Starting point for Tyr-containing synthetic strategies |
Why Protect Tyr with tBu?
In some short peptide syntheses, unprotected Tyr can be used because transient O-acylation may subsequently be reversed.
However, tBu protection provides a more controlled process by preventing unnecessary consumption of activated amino acid through phenolic O-acylation.
Aapptec likewise describes Fmoc-Tyr(tBu)-OH as the preferred tyrosine derivative for Fmoc solid-phase synthesis for this reason.
Tyrosine Is More Than an Aromatic Residue
Tyrosine combines a hydrophobic aromatic ring with an ionizable phenolic hydroxyl.
This allows Tyr to participate in:
aromatic interactions
hydrogen bonding
protein-binding interfaces
phosphorylation-dependent signaling
peptide polarity control
Consequently, Tyr→Phe substitution is commonly useful in SAR because it removes the phenolic OH while largely preserving aromatic size.
Phosphotyrosine and Sulfotyrosine Require a Different Strategy
Fmoc-Tyr(tBu)-OH is designed to produce ordinary tyrosine after cleavage.
If a peptide requires phosphotyrosine, sulfotyrosine or another phenolic modification, a specialized building block/protecting strategy is normally preferred.
Alan Scientific practical view: for modified Tyr-containing peptides, the final chemical state of the phenol should be defined before selecting the building block.
Product Documents
A Safety Data Sheet (SDS / MSDS) is available for this product to support laboratory handling, storage and safety assessment.
📎 MSDS_Fmoc-Tyr(tBu)-OH_Product557.pdf
Related Technical Resources
Browse Standard Fmoc-Amino Acids.
Read Choosing Fmoc-Protected Amino Acids for Peptide Synthesis.
For modified Tyr peptides, visit Custom Peptide Synthesis.
Why Source Peptide Building Blocks from Alan Scientific?
Alan Scientific supplies protected amino acids and specialty peptide building blocks for conventional and modified peptide synthesis.
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