aryl halide

An aryl halide is an organic compound where a halogen atom is bonded to an aromatic ring. These compounds are typically prepared through two main methods: direct halogenation of an aromatic ring or through reactions involving diazonium salts.123

While halogens on an aromatic ring can influence other reactions, they are generally less reactive than alkyl halides. Nucleophilic aromatic substitution, a reaction where a nucleophile replaces the halogen, is only practical if the aryl halide has a strong electron-attracting group, like a nitro group, positioned near the halogen.2

Aryl halides occur naturally in various forms, such as the iodine-containing amino acid l-thyroxine, which regulates metabolism. However, some synthetic aryl halides, like DDT and PCBs, have become widespread environmental pollutants due to their persistence and toxicity.4