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Question
Write a note on Stephen reaction.
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Solution
Nitriles are reduced to imine hydrochloride by stannous chloride in presence of hydrochloric acid which on acid hydrolysis give corresponding aldehydes. This reaction is called Stephen reaction.
\[\ce{\underset{(Alkane nitrile)}{R - C ≡ N +}2[H] ->[SnCl2, HCl]\underset{(Imine hydrochloride)}{R - HC = NH.HCl}->[H3O+]\underset{(Aldehyde)}{R - CHO} + NH4Cl}\]
e.g. \[\ce{\underset{(Ethanenitrile)}{H3C - C ≡ N}+2[H] ->[SnCl2, HCl][(reduction)]\underset{(Ethanimine hydrochloride)}{CH3 - HC = NH.HCl}->[H3O+]\underset{(Ethanal)}{CH3 - CHO} + NH4Cl}\]
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||\phantom{.........}\\
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