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| Product Name | Fmoc-Asn(Trt)-OH |
|---|---|
| Synonyms | Nα-Fmoc-Nγ-trityl-L-asparagine; Fmoc-L-Asn(Trt)-OH |
| Catalog No. | AS2485 |
| CAS Number | 132388-59-1 |
| Molecular Formula | C38H32N2O5 |
| Molecular Weight | 596.67 g/mol |
| SMILES | O=C(NC(C1=CC=CC=C1)(C2=CC=CC=C2)C3=CC=CC=C3)CC@@HNC(OCC4C5=C(C=CC=C5)C6=C4C=CC=C6)=O |
| Storage Temperature | Cool, dry place (≤25°C) |
| Appearance | White powder |
| Melting Point | 200–220°C |
| Specific Rotation | -14.5° ± 2° (C=1 in MeOH) |
| Functional Groups | Fmoc-protected α-amino group; Trt-protected asparagine side-chain amide; carboxylic acid |
| Primary Application | Fmoc solid-phase peptide synthesis (SPPS) |
Product Overview
Fmoc-Asn(Trt)-OH is a protected L-asparagine derivative widely used as a building block in Fmoc-based solid-phase peptide synthesis (SPPS).
The α-amino group is protected by Fmoc, while the side-chain amide of asparagine is protected with the trityl (Trt) group. This protecting-group strategy helps control side reactions during peptide assembly and is particularly important for maintaining the integrity of asparagine residues during repeated coupling and deprotection cycles.
During final acid-mediated cleavage and global deprotection, the Trt group is removed to regenerate the native asparagine side-chain amide.
Fmoc-Asn(Trt)-OH is therefore commonly selected for the preparation of asparagine-containing linear peptides, modified peptides, peptide libraries and complex research sequences.
Applications in Peptide Synthesis
| Application | Role of Fmoc-Asn(Trt)-OH |
|---|---|
| Fmoc Solid-Phase Peptide Synthesis | Standard protected building block for incorporation of L-asparagine into peptide sequences |
| Asparagine-Containing Peptides | Provides controlled introduction of Asn while protecting the side-chain amide during synthesis |
| Difficult Peptide Synthesis | Trt protection helps reduce unwanted side reactions involving the asparagine side chain |
| Peptide Library Synthesis | Suitable for parallel preparation of sequence-diverse Asn-containing peptides |
| Modified Peptide Synthesis | Can be incorporated into peptides containing terminal, fluorescent or other compatible modifications |
| Structure–Activity Relationship Studies | Supports preparation of Asn-containing analogs for systematic sequence and activity studies |
| Custom Peptide Synthesis | Used as a protected amino-acid building block in research-scale peptide production |
Fmoc-Asn(Trt)-OH in Fmoc-SPPS
During Fmoc-SPPS, Fmoc-Asn(Trt)-OH is activated and coupled to the resin-bound peptide chain using standard peptide coupling chemistry.
After coupling, the Fmoc group is removed under basic conditions to expose the α-amino group required for the next elongation cycle. The Trt group remains on the asparagine side chain throughout routine Fmoc deprotection and coupling steps.
At the end of peptide assembly, final acidic cleavage removes the Trt protecting group together with other acid-labile side-chain protecting groups.
This orthogonal behavior makes Fmoc-Asn(Trt)-OH compatible with standard Fmoc/tBu solid-phase peptide synthesis strategies.
Why Protect the Asparagine Side Chain with Trt?
Although the asparagine side chain is an amide rather than a strongly reactive amine or hydroxyl group, leaving it completely unprotected during peptide synthesis can increase the risk of unwanted chemistry under certain activation and cleavage conditions.
Trityl protection is widely used because it provides a useful balance between stability during chain assembly and acid-labile removal during final cleavage.
For peptide chemists, the purpose of Trt protection is therefore not simply to “block” the side chain. It is to maintain better synthetic control over the asparagine residue while preserving compatibility with the overall Fmoc-SPPS workflow.
This becomes increasingly important in long, aggregation-prone or high-purity peptide projects, where small amounts of side-product formation can complicate downstream purification.
Asparagine and Aspartimide-Related Considerations
Asparagine-containing sequences should also be evaluated in the context of neighboring residues and the overall peptide sequence.
During Fmoc-SPPS, certain sequence environments can favor side reactions related to aspartimide formation or dehydration, particularly under repeated basic treatment. The actual susceptibility depends on sequence position, neighboring amino acids, protecting groups and synthesis conditions.
For difficult Asn-containing sequences, optimization may therefore involve adjustments to:
coupling conditions
Fmoc deprotection exposure
protecting-group strategy
resin choice
aggregation-control approaches
purification conditions
The building block should be considered as one component of the complete peptide synthesis strategy rather than in isolation.
Product Documents
A Safety Data Sheet (SDS / MSDS) is available for this product to support laboratory handling, storage and safety assessment.
📎 MSDS_Fmoc-Asn(Trt)-OH_AS2485.pdf
Related Technical Resources
Learn more about protected amino acids and peptide chain assembly in Solid-Phase Peptide Synthesis (SPPS): A Practical Guide.
Explore additional Standard Fmoc-Amino Acids for peptide synthesis applications.
Learn more about building-block selection in Amino Acids & Peptide Building Blocks.
For complete peptide projects, Alan Scientific also provides Custom Peptide Synthesis, including synthesis, purification, modification and analytical quality control.
Why Source Peptide Building Blocks from Alan Scientific?
Alan Scientific supplies protected amino acids and peptide building blocks for research and peptide synthesis applications, with competitive pricing, flexible ordering options and peptide synthesis technical support.
Researchers can source individual Fmoc amino acids or combine building-block procurement with custom peptide synthesis services according to project requirements.
Research Use Only