Question: What starting materials are needed to synthesize each azo compound?

a.

b.

Diazonium salts are used in the synthesis of different benzene derivatives.

Benzene undergoes nitration - reduction - diazotization – substitution. Therefore, for determining the starting material, the reverse of this reaction sequence should be followed

(a) Both the benzene rings in the azo compound have substituents but NH₂is a strong electron donor.

For determining the two starting materials, the diazonium ion must be bonded to the ring not to the NH₂

Break the molecule into two halves

Thus, the required starting materials needed to synthesize the azo-compound are:

Required starting material

(b) Both the benzene rings in the azo compound have substituents; but OH, is a strong electron donor.

For determining the two starting materials; the diazonium ion must be bonded to the ring and not to the OH bond

Thus, the required starting materials needed to synthesize the azo-compound are:

Required starting material