Martinet reaction

The Martinet reaction or Martinet dioxindole synthesis is a name reaction in organic chemistry . It was named after its French discoverer J. Martinet , who published the reaction in 1913. With the help of the reaction, dioxindole (sometimes also called indolinone) and its derivatives can be produced.

Overview reaction

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

Instead of aniline , an N- alkyl aniline or a similar arylamine can also be used. The product is a racemic mixture of the dioxindole, since a stereocenter is formed on the carbon atom of the hydroxyl group in the course of the reaction mechanism .

mechanism

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

Initially, the grips amino group of the aniline 1 , the carbonyl group of the Mesoxalsäuredimethylesters ( 2 in). Then a proton is transferred from nitrogen to oxygen 3 and an alcohol group 4 is formed. With formation of a keto group , methanol is split off from 4 . The aromatic now attacks the partially positively charged carbonyl group 5 and thus forms a five-membered ring 6 . Then another proton is transferred. An isomerization takes place from molecule 7 to 8 , which leads to a rearomatization of the six-membered ring 8 . The addition of a base initiates a saponification reaction , which leads to renewed splitting off of methanol 9 . In addition, the methyl ester group becomes a carboxy group 9 . After a final decarboxylation , the product 10 is obtained in the form of a racemic dioxindole [here: a 1 H -indolin-2-one ( 10 )].

If the reaction is carried out in air (i.e. in the presence of oxygen), the resulting dioxindole 10 reacts even further to form isatin ( 11 ):

Individual evidence

↑ ^a ^b ^c ^d Z. Wang (Ed.): Comprehensive Organic Name Reactions and Reagents, 3 Volume Set , John Wiley & Sons, Hoboken, New Jersey 2009 , pp. 1838–1839, ISBN 978-0-471-70450- 8 .
^ WC Sumpter: The Chemistry of Oxindole , Chem. Rev., 1945 , 37 (3), pp. 443-479 ( doi : 10.1021 / cr60118a003 ).
↑ A. Guyot, J. Martinet: Compt. Rend. , 1913 , 156 , p. 1625.
^ H. Krauch , W. Kunz, E. Nonnenmacher: Reactions of organic chemistry , 5th revised and expanded edition, Dr. Alfred Hüthig Buch Verlag, Heidelberg 1976 , p. 23, ISBN 3-7785-0363-4 .
^ WC Sumpter, FM Miller: The Chemistry of Heterocyclic Compounds, Volume 8, Indole and Carbazole Systems , John Wiley & Sons, Hoboken, New Jersey 2009 , p. 112, ISBN 978-0-470-18807-1 .

[Wang_1838-1] Z. Wang (Ed.): Comprehensive Organic Name Reactions and Reagents, 3 Volume Set , John Wiley & Sons, Hoboken, New Jersey 2009 , pp. 1838–1839, ISBN 978-0-471-70450- 8 .

[2] WC Sumpter: The Chemistry of Oxindole , Chem. Rev., 1945 , 37 (3), pp. 443-479 ( doi : 10.1021 / cr60118a003 ).

[3] A. Guyot, J. Martinet: Compt. Rend. , 1913 , 156 , p. 1625.

[Krauch_23-4] H. Krauch , W. Kunz, E. Nonnenmacher: Reactions of organic chemistry , 5th revised and expanded edition, Dr. Alfred Hüthig Buch Verlag, Heidelberg 1976 , p. 23, ISBN 3-7785-0363-4 .

[Sumpter_112-5] WC Sumpter, FM Miller: The Chemistry of Heterocyclic Compounds, Volume 8, Indole and Carbazole Systems , John Wiley & Sons, Hoboken, New Jersey 2009 , p. 112, ISBN 978-0-470-18807-1 .