5-Ethylthio-1H-Tetrazole(ETT)
CAS89797-68-2
5-(Ethylthio)-1H-tetrazole (ETT, CAS 89797-68-2) is a tetrazole-based activator for the coupling step of phosphoramidite oligonucleotide synthesis. ETT is more acidic and more soluble in acetonitrile than 1H-tetrazole, which makes it a common choice for RNA and other sterically hindered monomers. KingPharm supplies ETT for research and manufacturing, with a batch-specific certificate of analysis.
- CAS No.
- 89797-68-2
- Formula
- C3H6N4S
- Mol. weight
- 130.17 g/mol
- Appearance
- White to Off-white Powder
Product Description
5-(Ethylthio)-1H-tetrazole, commonly known as ETT, is a tetrazole-based activator used in phosphoramidite chemistry for oligonucleotide synthesis.
During the coupling step, ETT protonates the diisopropylamino group of a nucleoside phosphoramidite and forms a reactive tetrazolide intermediate, which then couples with the free 5′-hydroxyl group of the growing oligonucleotide chain.
Compared with 1H-tetrazole, ETT is more acidic (pKa about 4.3 against about 4.9) and dissolves in acetonitrile up to about 0.75 M. The higher acidity gives faster coupling for bulky monomers, and the higher solubility lowers the risk of crystallisation in synthesizer lines.
When evaluating ETT for a process, buyers usually check the assay, the water content, the clarity of a 0.25 M solution in acetonitrile, packaging integrity and batch-to-batch consistency.
Chemical Specifications
Identifiers
| CAS number | 89797-68-2 |
|---|---|
| Product name | 5-Ethylthio-1H-Tetrazole(ETT) |
| Chinese name | 5-乙硫基四氮唑 |
| IUPAC name | 5-(ethylsulfanyl)-1H-tetrazole |
| Synonyms | 5-Ethylsulfanyl-1H-Tetrazole; 5-(Ethylthio)Tetrazole; 5-(S-Ethylmercapto)-Tetrazole; 5-(Ethylthio)-1H-Tetrazole; 5-(Ethylmercapto)-1H-Tetrazole |
| Chinese synonyms | 5-乙硫基四唑; 5-乙硫基-1H-四唑; 5-乙硫基-1H-四氮唑; 5-(乙基硫代)-1H-四唑; 乙硫基四唑; ETT |
| Molecular formula | C3H6N4S |
| Molecular weight | 130.17 g/mol |
| SMILES | CCSC1=NN=NN1 |
Physical and chemical properties
| Appearance | White to Off-white Powder |
|---|---|
| Melting Point | 85.0-89.0 ( ℃ ) |
Applications
ETT is used at the coupling step of solid-phase oligonucleotide synthesis, usually as a solution in anhydrous acetonitrile.
DNA and RNA synthesis
ETT activates nucleoside phosphoramidites on automated DNA and RNA synthesizers, typically as a 0.25 M solution in anhydrous acetonitrile.
DNA and RNA synthesis
ETT activates nucleoside phosphoramidites on automated DNA and RNA synthesizers, typically as a 0.25 M solution in anhydrous acetonitrile.
Sterically hindered monomers
ETT is widely used for 2′-O-protected RNA phosphoramidites, such as 2′-O-TBDMS monomers, and other bulky monomers that couple slowly with 1H-tetrazole.
Sterically hindered monomers
ETT is widely used for 2′-O-protected RNA phosphoramidites, such as 2′-O-TBDMS monomers, and other bulky monomers that couple slowly with 1H-tetrazole.
Phosphitylation reactions
ETT can serve as a mildly acidic azole activator in the preparation of phosphoramidites and in other phosphitylation reactions.
Phosphitylation reactions
ETT can serve as a mildly acidic azole activator in the preparation of phosphoramidites and in other phosphitylation reactions.
Quality Documentation
The following documents can be provided for 5-Ethylthio-1H-Tetrazole(ETT) to support technical evaluation and purchasing. Documents are issued for the specific grade and batch supplied.
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Certificate of Analysis (COA) Batch-specific test results against the specification.
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Safety Data Sheet (SDS) Hazard identification, safe handling, storage and transport information.
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Product specification The release specification with test items, limits and methods.
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Method of Analysis (MOA) Detailed analytical procedures for the test methods listed in the specification.
Frequently Asked Questions
What is 5-(Ethylthio)-1H-tetrazole (ETT) used for?
5-(Ethylthio)-1H-tetrazole (ETT) is an activator for phosphoramidite chemistry. In oligonucleotide synthesis ETT activates the incoming nucleoside phosphoramidite during the coupling step, so that the phosphoramidite reacts with the 5′-hydroxyl group of the growing DNA or RNA chain.
What is 5-(Ethylthio)-1H-tetrazole (ETT) used for?
5-(Ethylthio)-1H-tetrazole (ETT) is an activator for phosphoramidite chemistry. In oligonucleotide synthesis ETT activates the incoming nucleoside phosphoramidite during the coupling step, so that the phosphoramidite reacts with the 5′-hydroxyl group of the growing DNA or RNA chain.
How does ETT compare with 1H-tetrazole?
ETT is more acidic than 1H-tetrazole (pKa about 4.3 against about 4.9) and more soluble in acetonitrile (about 0.75 M against about 0.5 M). The higher acidity gives faster coupling, which matters most for RNA and other bulky monomers, and the higher solubility lowers the risk of crystallisation in synthesizer lines.
How does ETT compare with 1H-tetrazole?
ETT is more acidic than 1H-tetrazole (pKa about 4.3 against about 4.9) and more soluble in acetonitrile (about 0.75 M against about 0.5 M). The higher acidity gives faster coupling, which matters most for RNA and other bulky monomers, and the higher solubility lowers the risk of crystallisation in synthesizer lines.
What concentration of ETT is used on an oligonucleotide synthesizer?
Most protocols use 0.25 M ETT in anhydrous acetonitrile, which corresponds to about 32.5 g of ETT per litre of solution. Higher concentrations, up to about 0.75 M, are used for demanding couplings.
What concentration of ETT is used on an oligonucleotide synthesizer?
Most protocols use 0.25 M ETT in anhydrous acetonitrile, which corresponds to about 32.5 g of ETT per litre of solution. Higher concentrations, up to about 0.75 M, are used for demanding couplings.
Why must ETT solutions be kept anhydrous?
Water competes with the 5′-hydroxyl group for the activated phosphoramidite and lowers coupling efficiency. ETT activator solutions are therefore prepared in anhydrous acetonitrile, typically with a water content below 30 ppm, and are protected from atmospheric moisture on the synthesizer.
Why must ETT solutions be kept anhydrous?
Water competes with the 5′-hydroxyl group for the activated phosphoramidite and lowers coupling efficiency. ETT activator solutions are therefore prepared in anhydrous acetonitrile, typically with a water content below 30 ppm, and are protected from atmospheric moisture on the synthesizer.
What is the CAS number of 5-Ethylthio-1H-Tetrazole(ETT)?
The CAS Registry Number of 5-Ethylthio-1H-Tetrazole(ETT) is 89797-68-2. 5-Ethylthio-1H-Tetrazole(ETT) is also known as 5-Ethylsulfanyl-1H-Tetrazole; 5-(Ethylthio)Tetrazole; 5-(S-Ethylmercapto)-Tetrazole.
What is the molecular formula and molecular weight of 5-Ethylthio-1H-Tetrazole(ETT)?
The molecular formula of 5-Ethylthio-1H-Tetrazole(ETT) is C3H6N4S, and its molecular weight is 130.17 g/mol.
Which quality documents are available for 5-Ethylthio-1H-Tetrazole(ETT)?
The following documents are available for 5-Ethylthio-1H-Tetrazole(ETT): Certificate of Analysis (COA); Safety Data Sheet (SDS); Product specification; Method of Analysis (MOA). Contact KingPharm to request the documents for a specific batch.
How can I request a quotation for 5-Ethylthio-1H-Tetrazole(ETT)?
Send an inquiry for 5-Ethylthio-1H-Tetrazole(ETT) (CAS 89797-68-2) with the required quantity, target specification, destination country and any documentation requirements. KingPharm will confirm availability, packaging, lead time and price.
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