THE OXIDATION OF 2 NEW 1,3-DIHYDROXYIMIDA ZOLIDINES - SYNTHESIS AND STRUCTURE OF NITRONYL NITROXIDE RADICALS

The two new 1,3-dihydroxyimidazolidines 3a and 3b were prepared by con densation of 4-formylbenzoic acid (2a) and sodium glyoxylate (2b) with 2,3-dimethyl-2,3-butanediylbis(hydroxylamine) sulfate (1). The 1,3-di hydroxyimidazolidines were oxidized with sodium periodate in water to form nitronyl nitroxide radicals. Oxidation of the 1,3-dihydroxyimidaz olidine 3a yielded the new radical 4a, whereas the product obtained fr om the 1,3-dihydroxyimidazolidine 3b was, due to decarboxylation, the unsubstituted radical 4c. The crystal structure of 4a was solved by si ngle-crystal X-ray diffraction, showing the molecules to be arranged i n zigzag chains as a consequence of intermolecular hydrogen bonds.