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Fmoc-N-Me-Thr-OH is Fmoc-protected N-methyl-L-threonine. The methyl group is on the backbone nitrogen, while the threonine side-chain hydroxyl remains free.
Backbone N-methylation changes hydrogen-bond donation and local steric demand in a way that a side-chain substitution does not. It is one of the design strategies covered in Alan Scientific's noncanonical amino-acid overview.
Product Information
| Product Name | Fmoc-N-Me-Thr-OH |
| Catalog No. | AS4195 |
| CAS No. | 252049-06-2 |
| Molecular Formula | C20H21NO5 |
| Molecular Weight | 355.39 g/mol |
| Building Block Type | Fmoc-protected N-methyl-L-threonine |
| Primary Applications | Backbone N-methylation; conformational peptide design; macrocycle SAR; specialized Fmoc-SPPS |
Why N-Methylation Changes the Backbone
After incorporation, the residue no longer contributes a backbone N-H donor at that peptide bond. This can alter local conformation, protease recognition, intramolecular hydrogen bonding, and sometimes permeability in constrained peptide systems.
The Thr Hydroxyl Is Unprotected
Unlike common Fmoc-Thr(tBu)-OH, this product does not include side-chain tBu protection in its name or formula. If the hydroxyl must remain inert during downstream chemistry, the sequence-specific route should account for possible O-acylation or other side reactions.
Coupling Is More Sterically Demanding
N-methyl amino acids are secondary amines during peptide-bond formation and frequently couple more slowly than conventional amino acids. Neighboring β-branched threonine geometry adds further steric demand.
Procurement and QC
Confirm CAS 252049-06-2, C20H21NO5, MW 355.39 g/mol, N-methyl substitution, and L-threonine stereochemistry (2S,3R).
Peptides containing one or more N-methyl residues can be evaluated through custom N-methyl 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
Where is the methyl group?
It is on the backbone amino nitrogen.
Is the threonine hydroxyl protected?
No additional side-chain protecting group is indicated in this product identity.
Why can N-methyl threonine be difficult to couple?
Both N-methylation and threonine β-branching increase steric demand.
Related Technical Resources
Review the current SPPS workflow