Sano, Isamu published the artcileIndican and analogs in human urine. I. Millon’s reaction of indoxylsulfate at room temperature, SDS of cas: 2642-37-7, the publication is Seikagaku (1955), 153-6, database is CAplus.
Human urine showed pink red color with Millon’s reagent at room temperature The color tone was apparently different from that of phenols. To sep. a compound which showed the reaction, 200 l. urine was treated with C, the C extracted with a mixture of H2O-NH4OH-BuOH-MeOH (8:1:1:0.5). The extract was taken to dryness and extracted with 60% EtOH to remove uric acid. The residue was further extracted with BuOH, the extract was chromatographed on cellulose powder, and the fraction showing the Millon’s reaction was collected and purified by Amberlite IR-4B to yield 167 mg. of crystals. The crystals showed the Millon’s reaction and were identified to be K indoxylsulfate. 8-Quinolinol and 7-hydroxyindoleacetic acid (I) also showed the Millon’s reaction, but the presence of I was not detected in urines of 50 individuals when examined by paper chromatography.
Seikagaku published new progress about 2642-37-7. 2642-37-7 belongs to indole-building-block, auxiliary class Indole,Salt,Sulfonate,Inhibitor,Inhibitor, name is Potassium 1H-indol-3-yl sulfate, and the molecular formula is C8H6KNO4S, SDS of cas: 2642-37-7.
Referemce:
https://www.nature.com/articles/s41429-020-0333-2,
Preparation of Indole Containing Building Blocks for the Regiospecific Construction of Indole Appended Pyrazoles and Pyrroles