Indoxyl

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:

File:Synthesis Indoxyl.svg

Indoxyl-Synthese: Anthanilic acid (1) reacts with chloroacetic acid to give phenylglycine-o-carboxylic acid. When treated in molten sodium carbonate, the 2-Indoxycarboxylic acid (3) decarboxylates to give indoxyl (4) .

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 and is titrated with Obermayer's reagent, which is a dilute solution of ferric chloride (FeCl₃) in hydrochloric acid (HCl).