Question

On which ring and at what position(s) of the compounds shown below will

electrophilic aromatic substitution take place? Explain your answer in detail.

(a)

C N

H

H3C

O

(b)

C N

H

O

O2N

CH3

(5)

2.3) The following scheme is proposed for the synthesis of 4-bromobenzoic acid:

NH2 NH2

Br2

i) NaNO2

/HCl

ii) CuCN

Br

CN

Br

CN

Br

H3O

+

Briefly discuss the limitations of the above scheme and then propose a route

that would accomplish the desired product.

Answer 1

b)