title: Permanganate ion oxidations. IX. Manganese intermediates (complexes) in the oxidation of 2,4(1H,3H)-pyrimidinediones.
abstract: Uniquely stable manganese intermediates (complexes) are formed from the permanganate ion oxidation of the 5,6-carbon-carbon double bond in several 2,4(1H,3H)-pyrimidinediones [uracil, (compound 7), 5-methyluracil (thymine, compound 5), and 6-methyluracil (compound 8)]. These manganese complexes, which represent some of the most stable intermediate manganese species observed thus far in the oxidation of carbon-carbon double bonds, show absorption maxima in the 285-296 nm region (epsilon max approximately 4500). The relative reactivities of 6-methyluracil: uracil: thymine are 1: 23 : 194 and the bimolecular oxidation process is characterized by relatively small deltaH++ values and large negative deltaS++ values.
mesh_terms: D001665:Binding Sites; D055598:Chemical Phenomena; D002621:Chemistry; D008345:Manganese; D011744:Pyrimidinones; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet
chemical_list: D011744:Pyrimidinones; D008345:Manganese