nucleophilic aromatic substitution

Nucleophilic aromatic substitution is a chemical process where a nucleophile—a substance with a negative charge or electron-rich nature—replaces a group attached to an aromatic ring, such as benzene. Unlike typical reactions, this occurs when the ring has certain groups that activate it for attack, often involving a temporary intermediate known as a Meisenheimer complex. The process involves the nucleophile attacking the ring, temporarily disrupting its structure, and then restoring stability by displacing the original group. This reaction type is useful in forming new compounds, especially in pharmaceutical and chemical synthesis.