to generate aryl compounds functionalized by trifluoromethyl substituent groups. This process of trifluoromethylation provides unique chemical properties with a wide variety of practical applications. Particularly, pharmaceuticals with CF3 groups have enhanced metabolic stability, lipophilicity, and bioavailability. Sandmeyer-type trifluoromethylation reactions feature mild reaction conditions and greater functional group tolerance relative to earlier methods of trifluoromethylation. An example of a Sandmeyer-type trifluoromethylation reaction is presented below. Hydroxylation The Sandmeyer reaction can also be used to convert aryl amines to phenols proceeding through the formation of an aryl diazonium salt as shown below. In the presence of copper catalyst, this reaction takes place readily at room temperature. The procedure reported by Cohen and coworkers calls for copper(I) oxide together with an excess of copper(II) nitrate in neutral water. This is in contrast to the classical procedure (known by the German name Verkochung), which calls for boiling the diazonium salt in aqueous acid, a process that is believed to involve the aryl cation instead of radical and is known to generate other nucleophilic addition side products in addition to the desired hydroxylation product. Triazene Treatment with a second equivalent of aniline would give a triazene. Compare, for example, diminazene (Berenil) and isometamidium chloride. References External links http://www.name-reaction.com/sandmeyer-reaction Substitution reactions Name reactions