Question

Identify the major product C formed in the following reaction sequence: 

• A. Propylamine
• B. Butylamine
• C. butanamide
• D. α-bromobutane acid

Answer 1

The Correct Option is A

Analyze the reaction sequence to determine the primary product C.

Step 1: 1-Iodopropane reaction with NaCN
The reactant is 1-iodopropane ($ \mathrm{CH_3 - CH_2 - CH_2 - I} $). Sodium cyanide ($ \mathrm{NaCN} $) is a nucleophile, initiating a nucleophilic substitution ($ S_N2 $ mechanism, favored for primary alkyl halides). The cyanide ion ($ \mathrm{CN}^- $) replaces the iodide ion ($ \mathrm{I}^- $).

Product A is propanenitrile (or butyronitrile):

$ \mathrm{CH_3 - CH_2 - CH_2 - I + NaCN \longrightarrow CH_3 - CH_2 - CH_2 - CN + NaI} $

Step 2: Partial hydrolysis of propanenitrile (A) using $ \mathrm{OH}^- $
Nitriles undergo hydrolysis under basic or acidic conditions. Partial hydrolysis yields an amide.

Product B is butanamide:

$ \mathrm{CH_3 - CH_2 - CH_2 - CN + H_2O \xrightarrow{OH^-} CH_3 - CH_2 - CH_2 - CONH_2} $

Step 3: Butanamide (B) reaction with $ \mathrm{Br_2} $ and $ \mathrm{NaOH} $
This is the Hofmann bromamide degradation (or Hofmann rearrangement). An amide reacts with bromine in aqueous sodium hydroxide to form a primary amine with one less carbon atom than the amide; the carbonyl group is eliminated as carbonate.

Butanamide ($ \mathrm{CH_3 - CH_2 - CH_2 - CONH_2} $) reacts with $ \mathrm{Br_2} $ and $ \mathrm{NaOH} $ to produce propylamine:

$ \mathrm{CH_3 - CH_2 - CH_2 - CONH_2 + Br_2 + 4NaOH \longrightarrow CH_3 - CH_2 - CH_2 - NH_2 + Na_2CO_3 + 2NaBr + 2H_2O} $

Final Product:
The major product C is propylamine.

The correct answer is (1) propylamine.

Final Answer:
The final answer is: $ \boxed{(1)} $