Page 178 - Pharm.Org.Chem I 05-PC101 (1)
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10/27/2025
Orientation in disubstitution products of
benzene
• If the two substituents are located so that the directive
influence of one substituent is reinforced by the other .
Dr. Marwa El-Wakil 53
Orientation in disubstitution products of benzene
• When the directive effect of one group opposes another,
then activating groups win out over deactivating groups;
that’s, ortho, para activators predominate over ortho, para
deactivators (halogens) and over the meta deactivators.
Note: substitution
can’t occur between
the 2 groups, due to
steric hinderence.
Dr. Marwa El-Wakil 54
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