Bufadienolides. 9. Isobufalin

George Pettit, T. R. Kasturi, John C. Knight, Knut A. Jaeggi

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Isobufalin methyl ester (4a) was prepared by methanolysis of bufalin (3) in the presence of sodium methoxide, and saponification of the 3β-acetoxy derivative 4b readily afforded isobufalin (4c). In each case, the configuration of the side-chain olefin was shown to be trans at positions 22 and 23 by proton magnetic resonance measurements. Isodigitoxigenin (7), acetal 8e, and dihydropyran 12a were prepared from digitoxin by way of digitoxigenin (6) as described in part 8. By a four-step reaction sequence via intermediates 12b-12d and 11a, both methyl esters 8e and 12a were converted into methyl 3β-acetoxy-14β,21-epoxy-5β-chol-20(21)-enate (11b). Dehydrogenation of methyl ester 11b employing 2,3-dichloro-5,6-dicyanobenzoquinone completed total synthesis of 3β-acetoxy-isobufalin methyl ester and therefore isobufalin.

Original languageEnglish (US)
Pages (from-to)1410-1414
Number of pages5
JournalJournal of Organic Chemistry
Volume35
Issue number5
StatePublished - 1970

Fingerprint

Bufanolides
Esters
Digitoxigenin
Magnetic resonance measurement
Digitoxin
Saponification
Acetals
Alkenes
Dehydrogenation
Methanol
Nuclear magnetic resonance
Derivatives

ASJC Scopus subject areas

  • Organic Chemistry

Cite this

Pettit, G., Kasturi, T. R., Knight, J. C., & Jaeggi, K. A. (1970). Bufadienolides. 9. Isobufalin. Journal of Organic Chemistry, 35(5), 1410-1414.

Bufadienolides. 9. Isobufalin. / Pettit, George; Kasturi, T. R.; Knight, John C.; Jaeggi, Knut A.

In: Journal of Organic Chemistry, Vol. 35, No. 5, 1970, p. 1410-1414.

Research output: Contribution to journalArticle

Pettit, G, Kasturi, TR, Knight, JC & Jaeggi, KA 1970, 'Bufadienolides. 9. Isobufalin', Journal of Organic Chemistry, vol. 35, no. 5, pp. 1410-1414.
Pettit G, Kasturi TR, Knight JC, Jaeggi KA. Bufadienolides. 9. Isobufalin. Journal of Organic Chemistry. 1970;35(5):1410-1414.
Pettit, George ; Kasturi, T. R. ; Knight, John C. ; Jaeggi, Knut A. / Bufadienolides. 9. Isobufalin. In: Journal of Organic Chemistry. 1970 ; Vol. 35, No. 5. pp. 1410-1414.
@article{9b43287fc35a45c78dcdf97f271e41a1,
title = "Bufadienolides. 9. Isobufalin",
abstract = "Isobufalin methyl ester (4a) was prepared by methanolysis of bufalin (3) in the presence of sodium methoxide, and saponification of the 3β-acetoxy derivative 4b readily afforded isobufalin (4c). In each case, the configuration of the side-chain olefin was shown to be trans at positions 22 and 23 by proton magnetic resonance measurements. Isodigitoxigenin (7), acetal 8e, and dihydropyran 12a were prepared from digitoxin by way of digitoxigenin (6) as described in part 8. By a four-step reaction sequence via intermediates 12b-12d and 11a, both methyl esters 8e and 12a were converted into methyl 3β-acetoxy-14β,21-epoxy-5β-chol-20(21)-enate (11b). Dehydrogenation of methyl ester 11b employing 2,3-dichloro-5,6-dicyanobenzoquinone completed total synthesis of 3β-acetoxy-isobufalin methyl ester and therefore isobufalin.",
author = "George Pettit and Kasturi, {T. R.} and Knight, {John C.} and Jaeggi, {Knut A.}",
year = "1970",
language = "English (US)",
volume = "35",
pages = "1410--1414",
journal = "Journal of Organic Chemistry",
issn = "0022-3263",
publisher = "American Chemical Society",
number = "5",

}

TY - JOUR

T1 - Bufadienolides. 9. Isobufalin

AU - Pettit, George

AU - Kasturi, T. R.

AU - Knight, John C.

AU - Jaeggi, Knut A.

PY - 1970

Y1 - 1970

N2 - Isobufalin methyl ester (4a) was prepared by methanolysis of bufalin (3) in the presence of sodium methoxide, and saponification of the 3β-acetoxy derivative 4b readily afforded isobufalin (4c). In each case, the configuration of the side-chain olefin was shown to be trans at positions 22 and 23 by proton magnetic resonance measurements. Isodigitoxigenin (7), acetal 8e, and dihydropyran 12a were prepared from digitoxin by way of digitoxigenin (6) as described in part 8. By a four-step reaction sequence via intermediates 12b-12d and 11a, both methyl esters 8e and 12a were converted into methyl 3β-acetoxy-14β,21-epoxy-5β-chol-20(21)-enate (11b). Dehydrogenation of methyl ester 11b employing 2,3-dichloro-5,6-dicyanobenzoquinone completed total synthesis of 3β-acetoxy-isobufalin methyl ester and therefore isobufalin.

AB - Isobufalin methyl ester (4a) was prepared by methanolysis of bufalin (3) in the presence of sodium methoxide, and saponification of the 3β-acetoxy derivative 4b readily afforded isobufalin (4c). In each case, the configuration of the side-chain olefin was shown to be trans at positions 22 and 23 by proton magnetic resonance measurements. Isodigitoxigenin (7), acetal 8e, and dihydropyran 12a were prepared from digitoxin by way of digitoxigenin (6) as described in part 8. By a four-step reaction sequence via intermediates 12b-12d and 11a, both methyl esters 8e and 12a were converted into methyl 3β-acetoxy-14β,21-epoxy-5β-chol-20(21)-enate (11b). Dehydrogenation of methyl ester 11b employing 2,3-dichloro-5,6-dicyanobenzoquinone completed total synthesis of 3β-acetoxy-isobufalin methyl ester and therefore isobufalin.

UR - http://www.scopus.com/inward/record.url?scp=0014780140&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0014780140&partnerID=8YFLogxK

M3 - Article

VL - 35

SP - 1410

EP - 1414

JO - Journal of Organic Chemistry

JF - Journal of Organic Chemistry

SN - 0022-3263

IS - 5

ER -