Organic Letters 2010-09-17

Base-promoted reaction of 5-hydroxyuracil derivatives with peroxyl radicals.

Riccardo Amorati, Luca Valgimigli, Gian Franco Pedulli, Stanislav A Grabovskiy, Natalia N Kabal'nova, Chryssostomos Chatgilialoglu

Index: Org. Lett. 12(18) , 4130-3, (2010)

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Abstract

Addition of millimolar amounts of a weak base (pyridines) dramatically accelerates the reaction with peroxyl radicals of two biologically relevant uracil derivatives, 5-hydroxyuracil (HU) and 5-hydroxy-6-methyluracil (HMU). This is due to the formation of small amounts of the deprotonated form (pK(a) = 8.1-8.5 in water), which reacts with peroxyl radicals much faster than the parent undissociated form, via formal H-atom transfer from the OH in the 5 position.