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Fmoc-Phe(4-NH2)-OH is Fmoc-protected 4-amino-L-phenylalanine. It retains the phenylalanine backbone while adding a free para-aniline on the aromatic ring.
The para-amino group creates a distinct chemical handle for downstream derivatization, but it also means this is not a side-chain-protected routine Phe monomer. It belongs to the functionalized noncanonical amino-acid space.
Product Information
| Product Name | Fmoc-Phe(4-NH2)-OH |
| Catalog No. | AS4196 |
| CAS No. | 95753-56-3 |
| Molecular Formula | C24H22N2O4 |
| Molecular Weight | 402.45 g/mol |
| Building Block Type | Fmoc-protected 4-amino-L-phenylalanine |
| Primary Applications | Para-aniline functionalization; noncanonical peptide synthesis; labeling and conjugation precursor chemistry; aromatic SAR |
The Para-Aniline Is the Key Functional Handle
The aromatic amine can be used in selected acylation, diazotization, linker, probe, or other derivatization strategies. An aniline is less nucleophilic than a typical aliphatic amine, so reaction conditions should be selected specifically for aromatic amine chemistry.
Free Side-Chain Amine Changes SPPS Planning
If the para-amino group must remain unmodified during peptide elongation, an additional orthogonal protection strategy may be required. If it is the intended reaction site, the sequence and modification order should be designed around that reactivity.
Aromatic SAR and Spatial Presentation
Relative to phenylalanine, the para-amino group adds polarity and hydrogen-bonding capability while preserving the aromatic ring. This makes the residue useful for probing interactions at solvent-exposed or functionalizable positions.
Procurement and QC
Confirm CAS 95753-56-3, C24H22N2O4, MW 402.45 g/mol, L stereochemistry, Fmoc protection, and an unprotected para-NH2 group. Major supplier safety data classify this material as harmful if swallowed and as a skin, eye, and respiratory irritant.
For site-selective labeling or derivatization of the aromatic amine within a peptide, the protection and modification sequence can be designed through custom modified peptide synthesis.
Product Documents
A Safety Data Sheet (SDS / MSDS) is available for this product to support laboratory handling, storage and safety assessment.
Certificates of Analysis (COAs) are batch-specific. Please contact us to request the COA for your product, and we will provide it by email.
Frequently Asked Questions
Is the para-amino group protected?
No. The current product identity contains a free 4-NH2 group on the aromatic ring.
Why is this different from ordinary Fmoc-Phe-OH?
It adds a para-aniline functional group to the phenyl ring.
Can it be used for labeling or conjugation?
Yes, in compatible chemistry, but the lower nucleophilicity of an aniline and the rest of the peptide must be considered.
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