Select the reagents that reduce nitriles to primary amines. Choose the correct answer from the options given below.
- A, B and C only
- A, D and E only
- A, C and D only
- B, D and E only
Answer
(3) A, C and D only
Solution
As per NCERT, nitriles on reduction with lithium aluminium hydride (LiAlH4) or catalytic hydrogenation produce primary amines:
R-C N H2/Ni R-CH2-NH2
A. (i) LiAlH4; (ii) H2O ⇒ R–CH2NH2 (reduces)
B. Sn + HCl is used to reduce nitro compounds to amines, not nitriles (does not reduce)
C. H2/Ni (catalytic hydrogenation) ⇒ R–CH2NH2 (reduces)
D. Na(Hg)/C2H5OH (Mendius reduction) ⇒ R–CH2NH2 (reduces)
E. Br2/aq. NaOH is the Hofmann bromamide reagent (amide → amine), not a reducing agent for nitriles (does not reduce)
∴ A, C and D only
Answer: (3)