$2769.00 - $8308.00
Fmoc-N(Et)-D-Ala-OH is a backbone N-ethylated D-alanine derivative for peptide synthesis. It combines two noncanonical design variables in one residue: D stereochemistry at the alpha carbon and N-ethyl substitution on the backbone nitrogen.
These changes should be considered separately. D configuration changes stereochemical recognition, while N-ethylation removes one backbone N-H donor and adds steric bulk directly at the amide nitrogen after incorporation.
Product Information
| Product Name | Fmoc-N(Et)-D-Ala-OH |
| Catalog No. | AS2107 |
| CAS No. | 1283761-38-5 |
| Molecular Formula | C20H21NO4 |
| Molecular Weight | 339.39 g/mol |
| Building Block Type | Fmoc-protected N-ethyl D-alanine |
| Primary Applications | Backbone N-alkylation; D-amino-acid peptide SAR; conformational design; specialized Fmoc-SPPS |
Why N-Ethylation Is More Than a Hydrophobic Substitution
Backbone N-alkylation changes hydrogen-bonding capacity and conformational preferences in a way that a side-chain substitution does not. We consider this especially important in macrocycles and constrained peptides where one N-alkylated bond can alter local folding or permeability.
D Configuration Adds a Second Design Variable
This product is specifically D-Ala-derived. The D and L forms have the same nominal mass, so mass spectrometry alone cannot establish stereochemistry. Researchers using D residues for protease-resistance or conformational studies can compare broader options in Alan Scientific's D-form amino acid portfolio.
Coupling Can Be Sterically Demanding
N-alkylated amino acids are often more difficult to couple than conventional primary amino acids because the reacting nitrogen is more substituted. Incomplete incorporation can create deletion impurities that are difficult to separate later. We recommend checking sequence context before assuming a standard coupling cycle will be sufficient.
Where It Fits in Peptide Design
N-alkylated residues are commonly used to probe conformation, proteolytic stability and passive-permeability behavior. The broader design rationale is discussed in noncanonical amino acids in peptide discovery.
Procurement and QC Considerations
Confirm CAS 1283761-38-5, MW 339.39 g/mol and D stereochemistry on the lot-specific documentation. If several N-alkylated residues are present, route feasibility should be reviewed as part of specialized custom 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
What makes this residue noncanonical?
It combines D stereochemistry with backbone N-ethyl substitution.
Can LC-MS distinguish D from L?
No. Enantiomers have the same mass; stereochemical identity requires structure-specific documentation or chiral analysis.
Why can coupling be difficult?
The N-ethyl substituent increases steric demand around the reacting backbone nitrogen.
Related Technical Resources
Explore noncanonical amino-acid design
Review difficult coupling and deletion risks