Zinin reaction or Zinin reduction was discovered by a Russian organic chemist
Nikolay Zinin Nikolay Nikolaevich Zinin (russian: link=no, Никола́й Никола́евич Зи́нин; 25 August 1812, in Shusha – 18 February 1880, in Saint Petersburg) was a Russian organic chemist.
Life
He studied at the University of Kazan where ...
(Russian: Николай Николаевич Зинин) (25 August 1812, Shusha – 18 February 1880, Saint Petersburg). This reaction involves conversion of
nitro
Nitro may refer to:
Chemistry
*Nitrogen, a chemical element and a gas except at very low temperatures, with which many compounds are formed:
**Nitro compound, an organic compound containing one or more nitro functional groups, -NO2
**Nitroalkene, ...
aromatic compounds like
nitrobenzene
Nitrobenzene is an organic compound with the chemical formula Phenyl, C6H5Nitro compound, NO2. It is a water-insoluble pale yellow oil with an almond-like odor. It freezes to give greenish-yellow crystals. It is produced on a large scale from be ...
to
amine
In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituent ...
s by reduction with sodium
sulfide
Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds la ...
s. The reaction exhibits excellent selectivity for the nitro group and is useful in cases where other easily reduced functional groups (e.g., aryl halides and C=C bonds) are present in the molecule. Moreover, dinitrobenzenes can often be reduced selectively to the nitroaniline.
Reaction mechanism
The precise details of the reaction mechanism remain obscure, but a basic outline is known.
The
stoichiometry
Stoichiometry refers to the relationship between the quantities of reactants and products before, during, and following chemical reactions.
Stoichiometry is founded on the law of conservation of mass where the total mass of the reactants equ ...
for the reaction is:
:ArNO
2 + 3 H
2S → ArNH
2 + 3 S + 2 H
2O
Mechanistic studies have shown that disulfide (which is likely to be generated ''in situ'') is a more active reducing agent and may be involved. The reaction is believed to proceed through oxygen transfer to sulfur to give ArNO, followed by further reduction to ArNHOH and, finally, to ArNH
2.
Other Examples
* Reduction of 4,6 (5,7)-dinitro and 5,6-dinitrobenzimidazoles
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References
Name reactions
Organic reduction reactions
Organic redox reactions
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