Die Oxidation zweier neuer 1,3‐Dihydroxyimidazolidine – Darstellung und Struktur von Nitronylnitroxid‐Radikalen

The Oxidation of Two New 1,3‐Dihydroxyimidazolidines – Synthesis and Structure of Nitronyl Nitroxide Radicals The two new 1,3‐dihydroxyimidazolidines 3a and 3b were prepared by condensation of 4‐formylbenzoic acid (2a) and sodium glyoxylate (2b) with 2,3‐dimethyl‐2,3‐butanediylbis‐(hydroxylamine) sulfate (1). The 1,3‐dihydroxyimidazolidines were oxidized with sodium periodate in water to form nitronyl nitroxide radicals. Oxidation of the 1,3‐dihydroxyimidazolidine 3a yielded the new radical 4a, whereas the product obtained from the 1,3‐dihydroxyimidazolidine 3b was, due to decarboxylation, the unsubstituted radical 4c. The crystal structure of 4a was solved by single‐crystal X‐ray diffraction, showing the molecules to be arranged in zigzag chains as a consequence of intermolecular hydrogen bonds.