Original scientific paper

On the Optical Activity of Steroidal 5,7-Dienes

R. B. Koolstra ; Gorlaeus Laboratories, Leiden University, Department of Chemistry, PO Box 9502, 2300 RA Leiden, The Netherlands
H. J. C. Jacobs ; Gorlaeus Laboratories, Leiden University, Department of Chemistry, PO Box 9502, 2300 RA Leiden, The Netherlands
H. P. J. M. Dekkers ; Gorlaeus Laboratories, Leiden University, Department of Chemistry, PO Box 9502, 2300 RA Leiden, The Netherlands

Abstract

Circular dichroism (CD) data are reported of a series of 9,10-
stereoisomeric steroidal 5,7-dienes. In general the effects in the
longest wavelength transition (270-280 nm) are large (Mm" 10---30)
and consignate with respect to the diene helicity rule. The magnitude
of the CD appears to vary markedly with the substituent at C-3 and at C-17, and with solvent. In the case of the 9a,10p-H dienes, variation of solvent and temperature can affect even the sign of the Cotton effect. This is explained from a change of geometry of the diene ring: solvation, substitution and temperature can affect the average geometry of the ring including the values of the angle of twist of the diene (ef> (6-7». The relevance of the observed chiroptical data for the theoretical description of the optical activity in the So-+ Sl transition of homoannular cisoid dienes is discussed.

Keywords

Hrčak ID:

175386

URI

https://hrcak.srce.hr/175386

Publication date:

30.6.1989.

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