Staško A, Zalibera M, Barbieriková Z, Rimarčík J, Lukeš V, Bella M, Milata V, Brezová V. Anodic oxidation of selenadiazoloquinolones in alkaline media.
MAGNETIC RESONANCE IN CHEMISTRY : MRC 2011;
49:168-174. [PMID:
21246625 DOI:
10.1002/mrc.2716]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 11/24/2010] [Accepted: 11/30/2010] [Indexed: 05/30/2023]
Abstract
Newly synthesized derivatives of 6-oxo-6,9-dihydro[1,2,5]selenadiazolo[3,4-h]quinoline variously substituted at position 7 (R = H, COOH, COCH(3), CN, COOC(2)H(5) and COOCH(3)) are established in strongly alkaline aqueous solutions (0.1 M NaOH; pH ∼ 13) as N(9)-deprotonated structures, but in less alkaline solutions (0.001 M NaOH; pH ∼ 11) the N(9)-protonated oxo tautomeric forms dominate. Upon their anodic oxidation in alkaline solutions, the selenadiazole ring is replaced, forming instead the paramagnetic species analogous to the ortho semiquinone radical anions as monitored by in situ EPR spectroscopy. The quantum chemical calculations for two representative selenadiazoloquinolones (R = H and COOH) and their anodic oxidation products presented are in agreement with experiments.
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