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| Product Name | Fmoc-Thr(tBu)-OH |
|---|---|
| Synonyms | Fmoc-O-tert-butyl-L-threonine |
| Catalog No. | AS0707 |
| CAS Number | 71989-35-0 |
| Molecular Formula | C23H27NO5 |
| Molecular Weight | 397.46 g/mol |
| Appearance | White powder |
| Melting Point | 125–135°C |
| Specific Rotation | +16° ± 2° (C=1 in EtOAc) |
| Storage Temperature | Cool, dry place (≤25°C) |
| Side-Chain Protection | tert-Butyl-protected hydroxyl |
| Primary Application | Fmoc-SPPS |
Product Overview
Fmoc-Thr(tBu)-OH (CAS 71989-35-0; catalog AS0707) is an Fmoc-protected L-threonine building block with tert-butyl ether protection on the side-chain hydroxyl. It is used for introducing Thr during Fmoc solid-phase peptide synthesis. The alpha-carboxyl group remains free for coupling, while the beta-branched side chain retains its specified stereochemistry.
Quality Specifications and Ordering
Purity: Alan Scientific supplies Fmoc-Thr(tBu)-OH at >99% purity.
Catalog pack sizes: 25 g, 100 g, 500 g, and 1 kg.
Quality documentation: See Product Documents below for lot-specific COA request details. Review the analytical methods and results reported for the supplied batch.
Quotation: Email [email protected] with AS0707, the pack size, total quantity, delivery destination, and required date. Confirm availability and dispatch lead time before ordering.
Confirm the required threonine stereoisomer and O-tBu protection. Identify any stereochemical tests needed for supplier qualification before ordering.
Beta Branching and Hydroxyl Protection
Threonine carries both a methyl group and a protected hydroxyl close to the peptide backbone. Compared with serine, this changes steric requirements and introduces a second stereocenter. Coupling behavior should be evaluated in the actual sequence, particularly near other hindered residues.
The O-tBu group is intended to remain during routine basic Fmoc removal and to be removed during compatible final acidic deprotection. It is a side-chain ether, not an ester on the alpha-carboxyl group. Standard side-chain protection does not guarantee complete coupling or prevent all resin-bound aggregation.
For monitoring coupling and selecting a response to a difficult sequence, consult the SPPS practical guide rather than applying a universal repeat-coupling rule.
Threonine-Containing Research Sequences
Applications include Thr-containing research peptides, Ser-to-Thr comparison panels, and analogue studies examining side-chain sterics and hydrogen-bonding geometry. An allo-threonine derivative has different stereochemistry and should not be substituted for the specified L-threonine building block.
This material is not a phosphothreonine or glycosylated threonine derivative. For those targets, define the modification state and its installation route before choosing protecting groups. Biological effects of changing Ser to Thr, or of adding a modification, need experimental assessment in the complete peptide.
Product Documents
A Safety Data Sheet (SDS / MSDS) is available for this product to support laboratory handling, storage and safety assessment.
Certificates of Analysis are batch-specific. Please contact us to request a COA, and we will provide it by email.
Frequently Asked Questions
What should I verify before replacing a Fmoc-Thr(tBu)-OH supplier?
Compare the exact threonine stereoisomer, O-tBu protection, purity method, and any separately specified allo-isomer or other stereochemical limits. Request the lot-specific COA and assess performance in your route. The >99% purity specification alone does not establish every stereochemical attribute.
Can Fmoc-Thr(tBu)-OH be replaced by an allo-Thr derivative?
Only for an intentional stereochemical change to the target. The additional side-chain stereocenter makes the two structures distinct.
Does every Thr coupling need stronger activation?
No. Adjustments should follow evidence of incomplete conversion and consideration of sequence, protection, and resin accessibility.
Research Use Only
For research use only. Not for human or veterinary use.