Ring Opening of 3(2H)-Pyrazolones by Oxidation with Periodate

Article abstract of DOI:10.1002/ardp.19883210912

In contrast to the aminopyrazolones 1 the pyrazolones 3 and 5 are stable against singlet oxygen.However, no difference is observed in reaction of the title compounds 1, 3 and 5 with sodium metaperiodate forming the oxidation products 2, 4 and 6, respectively.The (1)H- and (13)C-nmr-spectra of 4 as well as those of 2 are complex due to the existence of rotameric isomers at room temperature.