$213.00 - $1090.00
Fmoc-Thr(tBu)-OPfp is the pentafluorophenyl active ester of Fmoc-Thr(tBu). The threonine hydroxyl is protected as tBu, while the carboxyl group is already converted into a reactive Pfp ester.
This makes it fundamentally different from a standard amino-acid free acid. It is a preactivated coupling reagent and should be handled with moisture and nucleophile exposure in mind.
Product Information
| Product Name | Fmoc-Thr(tBu)-OPfp |
| Catalog No. | AS4193 |
| CAS No. | 117088-31-0 |
| Molecular Formula | C29H26F5NO5 |
| Molecular Weight | 563.52 g/mol |
| Building Block Type | Activated pentafluorophenyl ester of Fmoc-Thr(tBu) |
| Primary Applications | Preactivated peptide coupling; protected fragment synthesis; solution-phase amide formation; specialty peptide chemistry |
Why the Pfp Ester Is Useful
Pentafluorophenyl esters are activated toward aminolysis and can be used to form amide bonds without generating the active ester in situ. This can simplify selected solution-phase or fragment-coupling steps when the activated derivative is stable enough to isolate and handle.
Activation Also Creates a Stability Tradeoff
A reagent designed to react with amines can also react with water or unintended nucleophiles. Storage, dryness, and timing between dissolution and coupling therefore matter more than for the corresponding free acid.
Threonine Side-Chain Protection
The side-chain hydroxyl remains protected as tBu during coupling. That reduces competing O-acylation and is compatible with later acid-mediated removal when the complete route permits.
Procurement and QC
Confirm CAS 117088-31-0, formula C29H26F5NO5, MW 563.52 g/mol, L-threonine stereochemistry, tBu side-chain protection, and Pfp ester identity. Major supplier information specifies refrigerated storage around 2-8°C.
For route design using active esters versus in-situ activation, Alan Scientific can evaluate the complete coupling sequence through 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 does OPfp mean?
It indicates a pentafluorophenyl ester, an activated carboxyl derivative.
Is this the same as Fmoc-Thr(tBu)-OH?
No. The carboxyl group has already been converted into an active ester.
Why should it be kept dry?
Hydrolysis consumes the activated ester and reduces effective coupling reagent content.
Related Technical Resources
Review peptide coupling in the SPPS guide