Martinet dioxindole synthesis

Martinet the reaction or Martinet Dioxindolsynthese is a name of reaction in organic chemistry. It was named after its French explorer J. Martinet, who published the reaction in 1913. With the help of the reaction, dioxindole leave (sometimes called Indolinone ) and produce its derivatives.

Overview reaction

Martinet, the reaction takes place in the absence of oxygen. In this reaction name aniline reacts with methyl or ethyl esters of mesoxalic acid for 1H- indoline -2-one, a dioxindole:

In place of aniline, a N- alkylaniline or a similar aryl amine can be used. The product is a racemic mixture of dioxindole matic, since in the course of the reaction mechanism on the carbon atom of the hydroxy group creates a stereo center.

Mechanism

The mechanism is illustrated here using the example of the reaction between aniline and Mesoxalsäuredimethylester.

Initially, the amino group of the aniline 1 attacks the carbonyl group of the Mesoxalsäuredimethylesters (2). After a proton from the nitrogen is transferred to oxygen 3 and an alcohol group 4 is formed. To form a keto group, a methanol molecule is cleaved from 4. Now the aromatic attacks the partially positively charged carbonyl group 5 and thus forms a five-membered ring 6 Subsequently, a proton is transferred again. Molecule of 7 to 8 is carried out isomerization, leading to a re-aromatization of six-membered ring 8. The addition of a base initiates a hydrolysis reaction, resulting in a renewed loss of methanol result 9 ​​Furthermore, from the methyl ester group, a carboxyl group 9 After a Final decarboxylation gives the product 10 in the form of a racemic dioxindole ( here: a 1H - indoline -2-one (10 ) ).

The reaction at the air ( that is, in the presence of oxygen ) is performed, the created dioxindole 10 responds to further isatin (11):