Bufadienolides. 29. Synthetic routes to bufotalin

Yoshiaki Kamano, George Pettit, Masuo Inoue

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Two partial syntheses of bufotalin (1a) were developed as follows. The 16-ketone 3 was prepared from cinobufagin and the 14,15β-epoxide group was reduced with chromous acetate to yield β-hydroxy ketone 4 (61%) and α,β-unsaturated ketone 5 (27%). Selective reduction of β-ketone 4 with Urushibara nickel A afforded alcohol 1b, which was acetylated to provide diacetate 1c. Treatment of diacetate 1c with hydrochloric acid in methanol gave bufotalin (1a) accompanied by lesser amounts of other hydrolysis products (1b, 1d, and 6a). In an alternative approach, α,β-unsaturated ketone 5 was first reduced with Urushibara nickel A to allylic alcohol 6a. After acetylation (to 6b) the olefin was subjected to reaction with hypoiodous acid or hypobromous acid and the resulting halohydrin (7a or 7b) was treated with Urushibara nickel A. The product of hydrogenolysis was bufotalin 3β-acetate (1c).

Original languageEnglish (US)
Pages (from-to)3007-3010
Number of pages4
JournalJournal of Organic Chemistry
Volume39
Issue number20
StatePublished - 1974

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Bufanolides
Ketones
Nickel
Acetates
Acetylation
Hydrogenolysis
Hydrochloric Acid
Epoxy Compounds
Alkenes
Methanol
Hydrolysis
Alcohols
bufotalin

ASJC Scopus subject areas

  • Organic Chemistry

Cite this

Bufadienolides. 29. Synthetic routes to bufotalin. / Kamano, Yoshiaki; Pettit, George; Inoue, Masuo.

In: Journal of Organic Chemistry, Vol. 39, No. 20, 1974, p. 3007-3010.

Research output: Contribution to journalArticle

Kamano, Y, Pettit, G & Inoue, M 1974, 'Bufadienolides. 29. Synthetic routes to bufotalin', Journal of Organic Chemistry, vol. 39, no. 20, pp. 3007-3010.
Kamano, Yoshiaki ; Pettit, George ; Inoue, Masuo. / Bufadienolides. 29. Synthetic routes to bufotalin. In: Journal of Organic Chemistry. 1974 ; Vol. 39, No. 20. pp. 3007-3010.
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