Song, Bo et al. published their research in Dyes and Pigments in 2009 | CAS: 146368-07-2

1-Ethyl-2,3,3-trimethyl-3H-indol-1-ium-5-sulfonate (cas: 146368-07-2) belongs to indole derivatives. Indole, first isolated in 1866, and it is commonly synthesized from phenylhydrazine and pyruvic acid, although several other procedures have been discovered. It is used in perfumery and in making tryptophan, an essential amino acid, and indoleacetic acid (heteroauxin), a hormone that promotes the development of roots in plant cuttings.Safety of 1-Ethyl-2,3,3-trimethyl-3H-indol-1-ium-5-sulfonate

The synthesis and photostability of novel squarylium indocyanine dyes was written by Song, Bo;Zhang, Qian;Ma, Wen-Hui;Peng, Xiao-Jun;Fu, Xin-Mei;Wang, Bing-Shuai. And the article was included in Dyes and Pigments in 2009.Safety of 1-Ethyl-2,3,3-trimethyl-3H-indol-1-ium-5-sulfonate This article mentions the following:

Novel, water-soluble, squarylium indocyanine dyes with various N-substituents on 3H-indolenine were synthesized. The maxima of absorption and emission wavelengths of the dyes in different solvents were in the range 628-670 nm and exhibited neg. solvatochromism with increasing solvent polarity in protic solvents. Dyes with N-benzyl rings (such as N-benzyl, N-carboxylbenzyl and N-fluorobenzyl) displayed greater photostability than dyes containing N-alkyl groups (such as N-Et and N-carboxylpentanyl) in aqueous solution The electron-withdrawing group (such as carboxyl and fluoro group) on the N-benzyl group of cyanine dyes improved photostability compared to dyes that contained an electron-donating group (such as methyl). The fading constant k of the N-carboxylbenzyl dye was considerably lower than that of the N-carboxylpentanyl dye. In the experiment, the researchers used many compounds, for example, 1-Ethyl-2,3,3-trimethyl-3H-indol-1-ium-5-sulfonate (cas: 146368-07-2Safety 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, first isolated in 1866, and it is commonly synthesized from phenylhydrazine and pyruvic acid, although several other procedures have been discovered. It is used in perfumery and in making tryptophan, an essential amino acid, and indoleacetic acid (heteroauxin), a hormone that promotes the development of roots in plant cuttings.Safety of 1-Ethyl-2,3,3-trimethyl-3H-indol-1-ium-5-sulfonate

Referemce:
Indole alkaloid derivatives as building blocks of natural products from聽Bacillus thuringiensis聽and聽Bacillus velezensis聽and their antibacterial and antifungal activity study,
Preparation of Indole Containing Building Blocks for the Regiospecific Construction of Indole Appended Pyrazoles and Pyrroles