Zinin reaction

Zinin reaction or Zinin reduction involves reduction of nitro aromatic compounds to the amines using sodium sulfide.^[1] It is used to convert nitrobenzenes to anilines.^[2][3] The reaction selectively reduces nitro groups in the presence of other easily reduced functional groups (e.g., aryl halides and C=C bonds) are present in the molecule.

Zinin reaction
Named after	Nikolay Zinin
Reaction type	Organic redox reaction

Reaction mechanism and example

The reaction requires water. Thiosulfate is one product. A possible stoichiometry for the reaction is:

4 ArNO₂   +   6 S^2-   + 7 H₂O → 4  ArNH₂   +   3 S₂O₃^2- + 6 OH^-

Mechanistic studies have implicated a role for disulfide that is generated in situ. Nitrosobenzenes (ArNO) and phenylhydroxylamine (ArNHOH) are probable intermediates.^[4]

Dinitrobenzenes can often be reduced selectively to the nitroaniline. ^[5]

History

The reaction was discovered by a Russian organic chemist Nikolay Zinin (Russian: Николай Николаевич Зинин) (25 August 1812, Shusha – 18 February 1880, Saint Petersburg).

References

1. Porter, H. K. (1973). "The Zinin Reduction of Nitroarenes". Organic Reactions. 20 (4): 455–481. doi:10.1002/0471264180.or020.04. ISBN 0471264180.
2. Zinin, N. (1842). "Beschreibung einiger neuer organischer Basen, dargestellt durch die Einwirkung des Schwefelwasserstoffes auf Verbindungen der Kohlenwasserstoffe mit Untersalpetersäure" [Description of some new organic bases, represented by the action of hydrogen sulphide on hydrocarbons with sub-nitric acid]. Journal für Praktische Chemie (in German). 27 (1): 140–153. doi:10.1002/prac.18420270125.
3. Richard Willstätter, Heinrich Kubli (1908). "Über die Reduktion von Nitroverbindungen nach der Methode von Zinin" [On the reduction of nitro compounds by the method of Zinin]. Berichte der deutschen chemischen Gesellschaft (in German). 41 (2): 1936–1940. doi:10.1002/cber.19080410273.
4. Porter, H. K. (2011), "The Zinin Reduction of Nitroarenes", Organic Reactions, John Wiley & Sons, Ltd, pp. 455–481, doi:10.1002/0471264180.or020.04, ISBN 978-0-471-26418-7, retrieved 2022-02-01
5. Sebla Dincer (2002). "The preferential reduction of 4,6 (5,7)-dinitro and 5,6-dinitrobenzimidazoles". Dyes and Pigments. 53 (3): 263–266. doi:10.1016/S0143-7208(02)00018-9.