[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.
The reaction requires water, with thiosulfate being formed as a by-product.
A possible stoichiometry for the reaction is: 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] for example in the synthesis of 3-nitroaniline from 1,3-dinitrobenzene The reaction was discovered by a Russian organic chemist Nikolay Zinin (Russian: Николай Николаевич Зинин) (25 August 1812, Shusha – 18 February 1880, Saint Petersburg).