Original scientific paper

Circular Dichroism of Bufadienolides

Brian Green ; Department of Chemistry, University of Maine at Orono, Orono, Maine 04469 (USA)
Feliksa Snatzke ; Lehrstuhl fur Strukturchemie, Ruhruniversitat, D-4630 Bochum 1 (FRG)
Gunther Snatzke ; Lehrstuhl fur Strukturchemie, Ruhruniversitat, D-4630 Bochum 1 (FRG)
George R. Pettit ; Cancer Research Institute and Dept. of Chemistry, Arizona State University, Tempe, Arizona 85287 (USA)
Yoshiaki Kamano ; Cancer Research Institute and Dept. of Chemistry, Arizona State University, Tempe, Arizona 85287 (USA)
Margaret L. Niven ; Dept. of Chemistry, University of Cape Town, Cape Town (South Africa)

Abstract

With the help of PMO theory a non-empirical sector rule has been derived for the n ~ 1t5* band CD (around 260 nm) of the pentadienolide chromophore of steroidal bufadienolides. The rule was verified by experiment using the preferred conformation for the 2-pyrone side chain found in most of the crystalline bufadienolides investigated by x-ray diffraction. Substituents in ring D do not drastically influence the Cotton effect of this transition, whereas the sign of the 1C4 ~ 1t5* band Cotton effect around 300 nm is strongly dependent on such substitutions. The Cotton effect of additional carbonyl groups can in general be detected without difficulty in the CD-spectra.

Keywords

Hrčak ID:

178029

URI

https://hrcak.srce.hr/178029

Publication date:

6.3.1986.

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