Fmoc-Ser(tBu)-OPfp: identity and synthesis considerations
Fmoc-Ser(tBu)-OPfp is the pentafluorophenyl active ester of N-Fmoc, O-tert-butyl-protected L-serine. It has an activated carboxyl group while the amino group and side-chain hydroxyl remain protected.
| Catalog No. | AS4167 |
|---|---|
| CAS No. | 105751-13-1 |
| Molecular formula | C28H24F5NO5 |
| Molecular weight | 549.49 g/mol |
Active ester versus free acid
Compared with Fmoc-Ser(tBu)-OH, this material is a preformed pentafluorophenyl ester. Assess the receiving amine, solvent, base and conversion; do not automatically apply a free-acid activation system.
Protecting the hydroxyl
The tert-butyl ether limits reaction at the serine hydroxyl during compatible assembly steps. Fmoc is normally removed under basic conditions and tBu under acidic conditions. Confirm compatibility with the full sequence.
Coupling decisions
Residual deprotection amines can compete with an active ester, and moisture can cause hydrolysis. For an N-methylglycine alternative, Fmoc-Sar-OPfp shares the active-ester concept but changes residue chemistry.
Product Documents
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 side-chain hydroxyl free?
No. It is protected as a tert-butyl ether.
Can it directly replace Fmoc-Ser(tBu)-OH?
They introduce the same protected residue but require different carboxyl activation planning.
Does OPfp protect nitrogen?
No. Fmoc protects nitrogen; OPfp is the carboxyl active ester.
Research Use Only. Not for human or veterinary use.