TCI C1926 O-(6-Chlorobenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium Tetrafluoroborate, commonly known as TCTU, is a uronium/aminium-class coupling reagent designed specifically for amide bond formation in peptide synthesis. The reagent works by activating a carboxylic acid group into an active ester derived from 6-chloro-1-hydroxybenzotriazole, which is then attacked by a free amine group to form the peptide bond. In peptide chemistry and medicinal chemistry laboratories, reagents of this type serve as the backbone of the residue assembly process because they determine the efficiency, speed, and stereochemical purity of the final product.
The property that makes TCTU a widely preferred choice is the presence of the chloro group on the benzotriazole ring. This electron-withdrawing substituent makes the resulting active ester more reactive than its non-chlorinated counterparts, so coupling proceeds faster and reaches completion more thoroughly, including on peptide sequences that are sterically difficult to assemble. This high reactivity also helps suppress racemization, because the activated residue reacts with the amine promptly before it has the opportunity to form an oxazolone intermediate. As a tetrafluoroborate salt, the reagent offers handling characteristics suited to routine synthetic work.
In Indonesian laboratories, TCTU is typically used in university research groups, pharmaceutical research and development units, and peptide chemistry facilities that carry out manual or automated solid-phase synthesis. It is generally selected when a coupling step has failed with a milder reagent, when a difficult sequence requires more aggressive activation, or when stereochemical integrity must be preserved across a long assembly. Analysts commonly pair it with a tertiary amine base in a polar aprotic solvent according to the established protocol for the target sequence.
- Solid-phase peptide synthesis (SPPS): the reagent activates the incoming protected amino acid rapidly, allowing each coupling cycle to reach completion before the next deprotection step begins on resin.
- Difficult and sterically hindered sequence coupling: the chlorinated benzotriazole active ester provides the elevated reactivity needed to drive acylation of aggregated or hindered chains to completion.
- Solution-phase amide bond formation: chemists apply the reagent to join carboxylic acid and amine fragments in medicinal chemistry work where a clean, fast condensation is required.
- Peptide fragment condensation: the low racemization tendency makes the reagent suitable for joining pre-assembled segments where stereochemical integrity at the junction residue is critical.
- Method development and coupling optimization studies: researchers use the reagent as a high-reactivity benchmark when comparing activation strategies, reaction times, and epimerization levels across protocols.
| Brand | TCI (Tokyo Chemical Industry) |
|---|---|
| CAS number | 330641-16-2 |
| Molecular formula | — |
| Purity | — |
| Category | Chemistry > Chemical Biology > Peptide Chemistry |
| Pack sizes | available in standard catalogue pack sizes; please confirm the currently listed packaging option |
| Physical form | — |
| Storage | keep in a cool, dry place in a tightly closed container, protected from moisture |
- Product Code: TCI C1926
Store the reagent in a cool, dry area inside a tightly closed original container, protected from moisture and away from incompatible materials. Uronium-type coupling reagents are sensitive to humidity, so the container should be kept sealed and returned to storage promptly after weighing; handling inside a desiccator or a dry environment is recommended for frequently opened stock. Weigh and dispense the material in a fume hood, and use gloves, safety goggles, and a laboratory coat. Avoid inhalation of dust and contact with skin or eyes. Follow the manufacturer's safety data sheet and institutional chemical waste procedures for disposal.
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