In organic chemistry, indoxyl is a nitrogenous substance with the chemical formula: C8H7NO. Indoxyl is isomeric with oxindol and is obtained as an oily liquid.

Preparation

The Heumann indigo synthesis starts from anthranilic acid:

In nature indoxyl is derived from indican, which is a glycoside. The hydrolysis of indican yields β-D-glucose and indoxyl.

Indigo dye is a product of the mild oxidation of indoxyl.

Indoxyl can be found in urine, when associated with indoxyl sulfate, a cardiotoxin, which is detected by titration with Obermayer's reagent, which is a dilute solution of ferric chloride (FeCl3) in hydrochloric acid (HCl).

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