Question

Which of the following is a Stephen reaction?

Options

• \[\begin{array}{cc}
  \phantom{.........................................}\ce{H}\\
  \phantom{.........................................}|\\
  \ce{R - C ≡ N + 2[H] ->[SnCl2][dil.HCl] R-CH = NH*HCl->[H3O+] R - C = O + NH4Cl}
  \end{array}\]

• \[\begin{array}{cc}
  \ce{R - C - R + 4[H] ->[Zn-Hg/conc. HCl][\Delta] R - CH2 - R + H2O}\\
  ||\phantom{...........................................}\\
  \ce{O}\phantom{...........................................}
  \end{array}\]

• \[\ce{R - COCl ->[H2][Pd-BaSO4] R - CHO + HCl}\]

• \[\ce{R - CH = O->[H2N - NH2][- H2O] R - CH = N - NH2 ->[KOH/ethylene glycol][\Delta] R - CH3 + N2}\]

Answer 1

\[\begin{array}{cc}
\phantom{.........................................}\ce{H}\\
\phantom{.........................................}|\\
\ce{R - C ≡ N + 2[H] ->[SnCl2][dil.HCl] R-CH = NH*HCl->[H3O+] R - C = O + NH4Cl}
\end{array}\]

Explanation:

The reaction is referred to as the Stephen reaction. The manufacture of aldehyde from nitriles utilising tin (II) chloride, hydrochloric acid, and quenching the resultant iminium salt with water is the goal of this reaction. Ammonium chloride is also created during the synthesis.

\[\begin{array}{cc}
\phantom{.........................................}\ce{H}\\
\phantom{.........................................}|\\
\ce{R - C ≡ N + 2[H] ->[SnCl2][dil.HCl] R-CH = NH*HCl->[H3O+] R - C = O + NH4Cl}
\end{array}\]