Electrophilic Aromatic Substitution on Substituted Benzenes

When a substituent is already present on an aromatic ring undergoing electrophilic aromatic substitution, three different products are possible ortho, meta, or para. The observed major product(s) depends on whether the substituent is an electron-donating group (EDG), an electron-withdrawing group 

Summary of Substituent Effects on Electrophilic Aromatic Substitution 

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