Isatin

• 2,3- Indolindion
• 2,3- Dioxoindolin

Orange red solid

Fixed

198-202 ° C

• Poorly soluble in water ( 1.9 g · l-1 at 20 ° C)
• Soluble in benzene

Template: Infobox chemical / molecular formula search available

Isatin is an organic compound and a derivative of indole.

History

Isatin was first isolated by the French chemist Auguste Laurent, until 1878 succeeded Adolf von Baeyer the total synthesis. In 1880, he developed a synthetic route starting from o- nitrocinnamic, 1883 he patented a synthesis of 2- nitrobenzaldehyde. It was therefore necessary Indigo no longer be won cumbersome from plants.

Production

Previously isatin could only be obtained from indigo. Today it is produced from benzoic acid derivatives or by the method of Sandmeyer.

Aniline ( 1) to α - isonitrosoacetanilide ( Hydroxyaminoacetanilid, 2 ) in the presence of chloral hydrate and hydroxylamine, forming the corresponding oxime. By the action of conc. Sulfuric acid is cyclized to this isatin 3- imide ( 3) and then finally to isatin (4) saponified.

Properties

Isatin is moderate and more soluble in hot water with orange color in cold water. In ethanol isatin with red -orange color is soluble. Is added to the heated aqueous solution of sodium carbonate something ( alkaline effect ), so the color changes to red - violet by deprotonation. With the addition of sodium dithionite to the solution is colorless to light yellow this. This is a reduction to the leuco form, there arises a corresponding diol instead of the ( atmospheric oxygen, for example ) can be achieved by a suitable oxidizing agent to re- oxidize dione. Thus, this process is an example of the vat dyeing.

Use

Isatin and its derivatives are important starting compounds for indigo ( the dye blue jeans ) and indigo dyes similar. Some drugs were prepared from isatin and its derivatives. Isatin itself is an endogenous MAO inhibitor. Nowadays isatin derivatives are no longer used in the pharmaceutical industry because of its hepatotoxic effects.