Bufadienolides. 10. 3β-Acetoxy-14β,21-epoxy-5β-bufanolide and Related Lactones1,2a

John C. Knight, George Pettit, Peter Brown

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

Methyl 3β-pyranyloxy-(21S)-methoxy-14β,21-epoxy-5β-(20S)-norcholanate (6a) and the axial acetal 6b each gave isodigitoxigenin (3a) on treatment with hydrochloric acid in aqueous acetic acid. Extension of this reaction to cholanate ester 7b gave 30-acetoxy-14β,21-epoxy-5β-bufanolide (4). The epoxide 9 prepared from 3β-acetoxy-14β,21-epoxy-5p-chol-20 (21)-enic acid (8b) spontaneously cyclized to give 7-lactones of type 11 rather than 8-lactone derivatives. In another potential approach to bufadienolides, 3β-pyranyloxy-23-mesyloxy-14β,21-epoxy-20-methoxy-5β-(20)-norcholane (7d) was converted into 3β-acetoxy-14β,21-epoxy-20-formylpregn-20 (21)-ene (15a). Condensation of aldehyde 15a with malonic acid took an unexpected course which culminated in formation of olefin 18.

Original languageEnglish (US)
Pages (from-to)1415-1419
Number of pages5
JournalJournal of Organic Chemistry
Volume35
Issue number5
DOIs
StatePublished - May 1 1970

ASJC Scopus subject areas

  • Organic Chemistry

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