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Synlett 2005(12): 1962-1963  
DOI: 10.1055/s-2005-871968
SPOTLIGHT
© Georg Thieme Verlag Stuttgart · New York

Urea-Hydrogen Peroxide Complex

Sandra Taliansky*
Instituto de Química Médica (CSIC), Juan de la Cierva 3, 28006 Madrid, Spain
e-Mail: staliansky@iqm.csic.es;
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Publication History

Publication Date:
20 July 2005 (online)

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Introduction

The hydrogen bonded urea-hydrogen peroxide complex [CO(NH2)2·H2O2, 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.