$28.57 - $85.71
Fmoc-Dab(Dde)-OH is an orthogonally protected L-2,4-diaminobutyric acid building block. Fmoc protects the alpha-amino group for standard Fmoc-SPPS cycles, while Dde masks the shorter gamma-amino side chain and can be removed selectively with hydrazine-based conditions.
This protection map gives a side-chain amine that can be exposed while the peptide remains on resin. It supports site-selective acylation, branching, labeling and cyclization. The broader sequence context should still be planned using the principles in our practical SPPS workflow guide because orthogonality depends on the full protecting-group set.
Product Information
| Product Name | Fmoc-Dab(Dde)-OH |
| Catalog No. | AS2118 |
| CAS No. | 235788-61-1 |
| Molecular Formula | C29H32N2O6 |
| Molecular Weight | 504.57 g/mol |
| Chemical Identity | Nalpha-Fmoc-Ngamma-Dde-L-2,4-diaminobutyric acid |
| Building Block Type | Orthogonally protected diamino-acid building block |
| Primary Applications | On-resin side-chain deprotection, branching, labeling, lactam formation and modified peptide synthesis |
Why Dab Is Not Just a Shorter Lysine
Dab places its side-chain amine two methylene units from the alpha carbon, versus four in lysine. This shorter reach changes steric accessibility and the geometry of branches or side-chain cyclizations. We consider Dab a design variable rather than merely a substitute for Lys.
What Dde Orthogonality Enables
After selective Dde removal, the exposed gamma amine can be acylated with a linker, fluorophore, lipid, chelator or another peptide segment. Hydrazine-based removal is chemically distinct from Fmoc deprotection, but the sequence should still be checked for hydrazine-sensitive functionality before the route is fixed.
Dde vs ivDde on a Related Diamino Acid
The related Fmoc-Orn(ivDde)-OH uses the bulkier ivDde group on an ornithine side chain. ivDde is generally selected when greater stability toward repeated piperidine exposure is desired. The comparison therefore involves both protecting-group behavior and side-chain length.
Procurement and QC Considerations
Confirm CAS 235788-61-1, formula C29H32N2O6, MW 504.57 g/mol and L-Dab stereochemistry. The COA should support both Fmoc/Dde protection and chromatographic identity. For modification projects, incomplete Dde removal or partial side-chain acylation can become difficult-to-separate peptide impurities, so reagent identity and on-resin reaction monitoring are both important.
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 is Fmoc-Dab(Dde)-OH used for?
It introduces a Dab residue whose side-chain amine can be selectively exposed for branching, labeling, acylation or cyclization.
How is Dde usually removed?
Dde is commonly removed under hydrazine-based conditions designed to leave the Fmoc/tBu protection scheme usable; exact conditions should be validated for the sequence.
How is Dab different from Orn or Lys?
Dab has a shorter amino-containing side chain, which changes the spatial position and cyclization geometry of side-chain modifications.
Related Technical Resources
Compare the ivDde-protected ornithine building block.
Review common side reactions before planning a multi-step on-resin modification.