Urea-Hydrogen Peroxide Complex

All articles of this category Introduction The hydrogen bonded urea-hydrogen peroxide complex [CO(NH 2 ) 2 ·H 2 O 2 , UHP] is a cheap and commercially available white crystalline solid (mp 84-86 °C, dec.) obtained by recrystallization of urea from commercially available 33% aqueous hydrogen peroxide. [ 1 ] Its stability at room temperature, high hydrogen peroxide content (36.2%) and the potential for releasing it in a controlled manner, [ 2 ] as well as its solubility in organic solvents (alcohols, dichloromethane) makes it a good and safe sub­stitute for anhydrous hydrogen peroxide (not available anymore) in most oxidation reactions. UHP has been used for the epoxidation of a wide range of alkenes. [ 3 ] It is capable of oxidizing a number of functional groups: nitriles to amides, [ 4 ] oximes to nitroalkanes, [ 5 ] sulfides to sulfoxides [ 6 ] or sulfones, [ 7 ] aldehydes to acids, [ 8 ] etc. UHP has also been found useful for heteroatom oxidation reactions, [ 9 ] as well as to carry out Baeyer-Villiger [ 10 ] and related reactions. In recent years, UHP has proved to be effective in solid state reactions, both under heating [ 11 ] or microwave irradiation, [ 12 ] so becoming an interesting eco-friendly reagent.