ISSN:
0030-4921
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The 17O chemical shifts for six cyclic ketones which serve as models for quinones, viz. cyclohex-2-enone (1), α-tetralone (2), anthrone (3), 4H-pyran-4-one (4), 1-benzopyran-4(4H)-one (5), xanth-9-enone (6), and for six quinones, viz. benzoquinone, naphthoquinone, anthraquinone, 2,5-dihydroxybenzoquinone 5,8-dihydroxynaphthoquinone and 1,4-dihydroxyanthraquinone, were measured in toluene at 90°C. A shielding effect of approximately 50 ppm per fused benzene ring was noted for the quinones and related carbocyclic ketones; however, the analogous series of heterocyclic fused ring ketones 4-6 showed only a slight fused-ring effect on the carbonyl chemical shift. A single 17O resonance was observed for 2,5-dihydroxybenzoquinone (358 ppm) and 5,8-dihydroxynaphthoquinone (283 ppm), indicating rapid proton exchange between the oxygen atoms of these compounds. However, 1,4-dihydroxyanthraquinone gave two discrete 17O signals at 441 and 87 ppm, indicating that in this case proton exchange between oxygen atoms is slow.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1270221205
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