91Ó°ÊÓ

Electrophilic substitution of disubstituted benzenes is controlled by effects like the inductive and resonance effects. The additive effects of both the groups is considered in disubstituted benzenes.

The given starting material can be converted to skeletal structures as:

a.

b.

Methoxy and methyl groups are ortho, para directing groups for the electrophilic aromatic substitution reaction. Among these groups, methoxy is the strong directing group. Halides are ortho, para directing groups but weak donating groups.

(1) (a) Among X and ${\mathrm{CH}}_3$groups, ${\mathrm{CH}}_3$is a good directing group. Hence the products formed can be given as:

Reaction 1 (a)

(1) (b) Among X and${\mathrm{CH}}_3$ groups,${\mathrm{CH}}_3$ is a good directing group. Hence the products formed can be given as:

Reaction 1 (b)

(2) (a) Among${\mathrm{OCH}}_3$ and${\mathrm{CH}}_3$ groups, ${\mathrm{OCH}}_3$is a good directing group. The products formed can be given as:

Reaction 2 (a)

(2)(b)The following products are formed for the second reaction:

Reaction 2 (b)