Question

Show how to convert substances like Benzene to Aniline or Phthalimide to N-alkyl phthalimide.

Hint:

Benzene → Aniline requires nitration followed by reduction, while phthalimide alkylation is a key step in Gabriel synthesis.

Answer 1

Concept: Organic conversions involve stepwise reactions such as electrophilic substitution, reduction, and nucleophilic substitution. These transformations are important in synthetic organic chemistry. 
1. Conversion of Benzene to Aniline: Step 1: Nitration of Benzene Benzene undergoes electrophilic substitution with concentrated nitric acid in presence of concentrated sulfuric acid. \[ C_6H_6 \xrightarrow{\text{conc. HNO}_3/\text{conc. H}_2SO_4} C_6H_5NO_2 + H_2O \] (Product: Nitrobenzene) 
Step 2: Reduction of Nitrobenzene Nitrobenzene is reduced using Sn/HCl, Fe/HCl, or catalytic hydrogenation. \[ C_6H_5NO_2 \xrightarrow{\text{Sn/HCl}} C_6H_5NH_2 \] (Product: Aniline) 
Overall Conversion: \[ C_6H_6 \rightarrow C_6H_5NO_2 \rightarrow C_6H_5NH_2 \] 
2. Conversion of Phthalimide to N-alkyl Phthalimide: This reaction is part of Gabriel synthesis (alkylation step). 
Step 1: Formation of Potassium Phthalimide Phthalimide reacts with KOH. \[ \text{Phthalimide} + KOH \rightarrow \text{Potassium phthalimide} + H_2O \] 
Step 2: Alkylation Potassium phthalimide reacts with alkyl halide. \[ \text{Potassium phthalimide} + R-X \rightarrow \text{N-alkyl phthalimide} + KX \] 
Importance: 
Intermediate step in Gabriel synthesis of primary amines. 
Prevents formation of secondary or tertiary amines.