ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
p-Cyclohexadienone-oximes show NMR.-signals for the syn-α-proton at about δ = 6,9; the syn-β-, the anti-α-and the anti-β-proton signals, however, appear in the region of δ = 6,0-6,4. This is based on a comparison of the NMR.-spectra of the oximes of spiro[5 · 5]undeca-1,4-diene-3-one and 4-bromo-spiro[5 · 5]undeca-1,4-diene-3-one and on IR.-spectroscopic data and steric considerations. These chemical shifts differ characteristically from those of the corresponding vinyl hydrogens of the parent p-cyclohexadienones; the difference must be attributed on the one hand to the effect of the syn-hydroxyl group and on the other to the nitrogen. On this basis it is possible to assign syn- and anti-configurations respectively to the oximes of steroidal A-ring dienones and even to determine quantitatively the composition of mixtures of the syn-anti isomers, which are usually difficult to separate.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19650480820
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