Stereochemical Studies. II. Conformational Analysis of ∆5-3-Keto Steroids

Malka Gorodetsky, Amnon Yogev, Yehuda Mazur

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11 Scopus citations


The conformation of ring A in ∆5-3-keto steroids was determined through ultraviolet absorption, circular dichroism, and optical rotatory dispersion data. In most of the ∆5-3-keto steroids investigated, a coupling of the two chromophores was observed as indicated by increased n → π* transitions and the appearance of π → π* transitions of the β,γ-unsaturated carbonyl group. Introduction of a C-7 keto function to a “coupled” ∆5-3-keto system caused additional enhancement of the n →π* transitions of the isolated C-3 carbonyl group and changed markedly the normal ultraviolet pattern of the α,β-unsaturated carbonyl chromophore. An absence of the interaction characteristics in 4,4niialkyl ∆5-3-ketones indicates a quasi-boat conformation for its ring A. Supporting evidence for the latter was found in the nmr data.

Original languageEnglish
Pages (from-to)699-704
Number of pages6
JournalJournal of Organic Chemistry
Issue number3
StatePublished - 1 Jan 1966
Externally publishedYes

ASJC Scopus subject areas

  • Organic Chemistry


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