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H-Thr(tBu)-OH is O-tert-butyl-L-threonine with a free alpha amino group and a tert-butyl-protected side-chain hydroxyl. CAS 4378-13-6 corresponds to the natural L-threonine stereochemical relationship, (2S,3R).
We recommend confirming both stereocenters for any protected threonine derivative used in a peptide project. A wrong allo isomer may pass a simple mass check yet alter conformation, coupling behavior or downstream bioactivity. Lot-specific structural identity is therefore more important than MW alone.
Product Information
| Product Name | H-Thr(tBu)-OH |
| Catalog No. | AS2008 |
| CAS No. | 4378-13-6 |
| Molecular Formula | C8H17NO3 |
| Molecular Weight | 175.23 g/mol |
| Chemical Identity | O-tert-Butyl-L-threonine; (2S,3R)-2-amino-3-(tert-butoxy)butanoic acid |
| Primary Applications | Protected threonine chemistry, peptide-fragment coupling and orthogonal synthesis |
Why threonine stereochemistry needs explicit control
Threonine has two stereocenters, so L-threonine, D-threonine and allo-threonine derivatives are distinct materials even when formulas and masses overlap. For sequence-sensitive synthesis, the residue assignment should include stereochemistry rather than relying on the shorthand Thr(tBu).
Using a free amino group with protected hydroxyl
The unprotected alpha amine allows N-terminal acylation or fragment extension, while the side-chain tert-butyl ether masks hydroxyl reactivity during subsequent steps. Acidic conditions can remove the tBu protection when the route requires the free threonine hydroxyl.
Procurement and QC Considerations
Confirm CAS 4378-13-6, the stated molecular formula and lot-specific analytical identity. Review the COA together with the MSDS when the material will be used in sequence-sensitive or process-development work.
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 stereochemistry does CAS 4378-13-6 represent?
It corresponds to O-tert-butyl-L-threonine with the (2S,3R) configuration.
Is the amino group protected?
No. The alpha amino group is free; the side-chain hydroxyl is protected as a tert-butyl ether.
Is H-Thr(tBu)-OH the same as an allo-threonine derivative?
No. Allo-threonine has a different stereochemical relationship and should be treated as a different building block.
Related Technical Resources
Browse related specialty peptide building blocks for protected amino acids, fragments and noncanonical synthesis intermediates.
For complete sequence work using this chemistry, see our custom peptide synthesis with protected residues.