60E - Organic Chemistry (Mcmurry)

Question

p-Aminobenzoic acid (PABA) is widely used as a sunscreen agent. Propose a synthesis of PABA starting from toluene.

Step-by-Step Solution

Answer

The toluene is converted to PABA by nitration of toluene, followed by oxidation, and then finally reduction of Nitro benzoic acid gives p-Aminobenzoic acid.

Step1: Conversion of toluene to p- Aminobenzoic acid.

Toluene is treated with concentrated nitric acid and sulphuric acid to form p-Nitro toluene, which on further oxidation converts into p-Nitro benzoic acid. On reduction of p-Nitro benzoic acid finally gives p-Aminobenzoic acid.

Step2: Synthesis of p-Aminobenzoic acid.

Result:

Toluene is converted to p-Aminobenzoic acid by undergoing nitration followed by oxidation and finally by reduction of nitrobenzene giving PABA.