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Tri-tert-butyl 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate, commonly called DOTA-tris(tBu ester), is a protected DOTA derivative in which three acetate carboxyl groups are tert-butyl esters and one carboxyl group remains free.
The free carboxyl group provides a practical route for amide-bond formation with an amino-functional partner while the other DOTA carboxylates stay protected. This makes the reagent relevant to chelator-bearing peptides and other conjugates that can be produced through custom peptide synthesis with specialized functional groups.
Product Information
| Product Name | Tri-tert-butyl 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate |
| Normalized Chemical Name | DOTA-tris(tBu ester) |
| Catalog No. | AS2119 |
| CAS No. | 137076-54-1 |
| Molecular Formula | C28H52N4O8 |
| Molecular Weight | 572.73 g/mol |
| Chemical Identity | DOTA-tris(t-butyl ester); tri-tert-butyl protected DOTA with one free acetate carboxyl |
| Building Block Type | Protected macrocyclic chelator precursor |
| Primary Applications | DOTA conjugation chemistry, chelator-functionalized peptides and metal-chelate precursor synthesis |
Why Leave One DOTA Carboxyl Group Free?
A single free carboxyl group creates a defined coupling handle while three tert-butyl esters suppress competing activation of the other acetate arms. After conjugation, the protected esters can be removed to restore the multicarboxylate DOTA coordination environment. We consider this protection pattern especially useful when the conjugation step must precede metal complexation.
DOTA Conjugation Is a Route-Design Problem
Successful use depends on more than activating the free acid. The peptide or partner molecule must tolerate the coupling conditions and the later acid treatment used to remove tert-butyl groups. Metal-sensitive reagents, acid-labile modifications and purification strategy should be considered before the chelator is introduced.
How It Differs from DOTA-GA(tBu)4
The related DOTA-GA(tBu)4 bifunctional chelator precursor contains a GA-derived side arm and four tert-butyl esters. DOTA-tris(tBu ester) instead exposes one acetate carboxyl directly. These are different conjugation architectures even though both ultimately generate DOTA-like metal-binding environments.
Procurement and QC Considerations
Confirm CAS 137076-54-1, formula C28H52N4O8 and MW 572.73 g/mol. The most important identity check is the exact protection map: three tert-butyl esters plus one free acid. HPLC/MS should be interpreted together with the drawn structure because partially deprotected DOTA species can create related-mass impurities.
Product Documents
A Safety Data Sheet (SDS / MSDS) is available for this product to support laboratory handling, storage and safety assessment.
MSDS_DOTA-tris-tBu-ester_AS2119
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 DOTA-tris(tBu ester) used for?
It is used as a protected DOTA precursor with one free carboxyl group for conjugation to amines before final deprotection and metal complexation.
Why are only three carboxyl groups tert-butyl protected?
Leaving one acid free creates a selective coupling handle while the other DOTA carboxylates remain protected.
Is it interchangeable with DOTA-GA(tBu)4?
No. The free coupling handle and side-arm architecture are different, so route compatibility should be checked against the exact structure used in the intended protocol.
Related Technical Resources
Compare DOTA-GA(tBu)4 for an alternative bifunctional architecture.
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