An efficient approach to the synthesis of water-soluble cyanine dyes using poly(ethylene glycol) as a soluble support was written by Jiang, Lin-Ling;Dou, Li-Fang;Li, Bao-Lin. And the article was included in Tetrahedron Letters in 2007.Quality Control of 1-Ethyl-2,3,3-trimethyl-3H-indol-1-ium-5-sulfonate This article mentions the following:
An efficient synthesis approach to unsym. water-soluble amphoteric cyanine dyes has been established. Loading and activation of a sulfoindolenium inner salt on polyethylene glycol (PEG) as a first step have been achieved via a simple strategy. The cyanine dyes are released by the attack of a heterocyclic carbon nucleophile and the cleavage of the PEG-bound hemicyanine. The efficient approach delivers cyanine dyes in high purity without the nontrivial chromatog. separation often encountered in a solution process. In the experiment, the researchers used many compounds, for example, 1-Ethyl-2,3,3-trimethyl-3H-indol-1-ium-5-sulfonate (cas: 146368-07-2Quality Control of 1-Ethyl-2,3,3-trimethyl-3H-indol-1-ium-5-sulfonate).
1-Ethyl-2,3,3-trimethyl-3H-indol-1-ium-5-sulfonate (cas: 146368-07-2) belongs to indole derivatives. Indole exists overwhelmingly in the 1H-indole form as do other simple indoles. Due to this activity, the indole ring system has become an important component or intermediate in the synthesis of heterocycles.Quality Control of 1-Ethyl-2,3,3-trimethyl-3H-indol-1-ium-5-sulfonate
Referemce:
Indole alkaloid derivatives as building blocks of natural products from Bacillus thuringiensis and Bacillus velezensis and their antibacterial and antifungal activity study,
Preparation of Indole Containing Building Blocks for the Regiospecific Construction of Indole Appended Pyrazoles and Pyrroles