Question

Draw the two reaction schemes for the two syntheses shown below. Be sure to include all starting materials, reagents, products, and reaction conditions.

1. 4-aminobenzenesulfonic acid + 1-naphthol

2. 4-aminobenzenesulfonic acid + salicylic acid

Answer 1

The process involves in two steps :

a) Diazotisation process : It uses the reagents like sodium nitrite, HCl and primary amine reactant like 4-aminobenzenesulfonic acid that form diazonium reactant which acts as electrophile

HCl + NaNO₂ ----> HO-N=O +H⁺ ----> H-O-N⁺(H)=O

b) Coupling process : It uses nucleophile like 1-naphol ion, salicylate ion that couples with the electrophile diazonium reactant that forms 4-(p-phenylazosulfonic acid)-1-napthol with 1-napthol and 4-(p-phenylazosulfonic acid)-1-salicylic acid with salicylic acid.