ISSN:
0749-1581
Keywords:
Anthracycline semiquinones
;
EPR
;
ENDOR
;
TRIPLE
;
Conformation
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The synthesis of five substituted anthraquinones related to anthracyclines is described. One-electron reduction of these compounds yields the corresponding semiquinones, which were characterized by EPR, ENDOR and TRIPLE resonance spectroscopy. The data indicate a rapid conformational interconversion of the cyclohexene moiety (ring A in the anthracyclines). The low-temperature structures could be assigned to half-chair conformers whose splitting constants and torsion angles were obtained by simple calculations. Introduction of substituents in the 4-position, disturbing the symmetry of the anthraquinone, results in remarkable changes in the spin density distribution, in contrast to published results. A reinterpretation and assignment of known anthraquinone radicals is presented.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260310510
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