Question

Devise a synthesis of each biologically active compound from benzene.

Short answer

a

b

Step-by-step solution

Chlorination

The organic reaction involving the replacement of hydrogen atom(s) by chloride ion in the presence of ferric chloride in an aromatic compound is known as the ‘chlorination reaction’.

a. Benzene is chlorinated to form the chlorobenzene which is treated with a strong base such as sodium hydroxide to form phenol. Phenol is nitrated to form ortho-nitro phenol which is reduced to form the corresponding p-amino phenol.

Formation of -amino phenol

Friedel-Craft Acylation

The reaction involving the introduction of an acyl group into an aromatic compound is known as the ‘Friedel-Craft Acylation’.

a. The p-aminophenol is treated with acetyl chloride in the presence of anhydrous aluminum chloride to undergo dehalogenation to form the required compound.

Formation of acetaminophen

b. Benzene is treated with 2-chloropropanoyl chloride followed by reduction of the carbonyl group. The compound is further treated with ethylamine in presence of hydrogen and any liquified solvent to form the required compound.

Formation of pseudo ephedrine