Page 176 - Pharm.Org.Chem I 05-PC101 (1)
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Note: Friedel-Crafts reactions fails on benzene rings
bearing one or more of these strongly electron-
withdrawing groups.
2025-2026 Dr. Marwa El-Wakil 49
• F.C. reactions do not occur when benzene ring carries OH or
NH2, because the amino or OH group is changed into powerful
electron-withdrawing group by the Lewis acids used to catalyze
Friedel–Crafts reactions
• Similarly, aniline and phenol can’t undergo nitration or
sulphonation (due to acidity of the medium)
2025-2026 Dr. Marwa El-Wakil 50
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