Bufadienolides. 3. A Synthetic Route to Isocardenolides

George Pettit; Brian Green; Arun K. Das Gupta; Philip A. Whitehouse; John P. Yardley

doi:10.1021/jo00830a027

Bufadienolides. 3. A Synthetic Route to Isocardenolides

George Pettit, Brian Green, Arun K. Das Gupta, Philip A. Whitehouse, John P. Yardley

Research output: Contribution to journal › Article › peer-review

13 Scopus citations

Abstract

A Bestmann reaction employing 3β-acetoxy-20-oxo-21-iodo-5-pregnene (2) and carbomethoxymethylenetriphenylphosphorane was used to complete a synthesis of methyl 3β-acetoxy-2-oxo-21-nor-5-imns-22-choladienate (1), which upon irradiation in sunlight gave cis isomer 5. Similarly, 3β-acetoxy-20-oxo-21-iodo-5,16-pregna-diene (6) was converted into trans side-chain olefin 7 and cis side-chain olefin 8. Palladium-catalyzed hydrogenation of triene 8 resulted in methyl 3-acetoxy-20-oxo-21-nor-5a-cholanate (9a) accompanied by small amounts of the corresponding 3-deoxy derivative 9b and 3β-acetoxy-20-hydroxy-21-nor-5a-cholanic acid γ-lactone (24 å 20). Subjecting triene 8 to sodium borohydride reduction in ethanol yielded isocardanolide 10. The principal objective, synthesis of isocardenolide 11, was realized by selective reduction of ketone 5 with sodium borohydride in dimethylformamide.

Original language	English (US)
Pages (from-to)	1381-1384
Number of pages	4
Journal	Journal of Organic Chemistry
Volume	35
Issue number	5
DOIs	https://doi.org/10.1021/jo00830a027
State	Published - May 1 1970

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Organic Chemistry

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title = "Bufadienolides. 3. A Synthetic Route to Isocardenolides",

abstract = "A Bestmann reaction employing 3β-acetoxy-20-oxo-21-iodo-5-pregnene (2) and carbomethoxymethylenetriphenylphosphorane was used to complete a synthesis of methyl 3β-acetoxy-2-oxo-21-nor-5-imns-22-choladienate (1), which upon irradiation in sunlight gave cis isomer 5. Similarly, 3β-acetoxy-20-oxo-21-iodo-5,16-pregna-diene (6) was converted into trans side-chain olefin 7 and cis side-chain olefin 8. Palladium-catalyzed hydrogenation of triene 8 resulted in methyl 3-acetoxy-20-oxo-21-nor-5a-cholanate (9a) accompanied by small amounts of the corresponding 3-deoxy derivative 9b and 3β-acetoxy-20-hydroxy-21-nor-5a-cholanic acid γ-lactone (24 {\aa} 20). Subjecting triene 8 to sodium borohydride reduction in ethanol yielded isocardanolide 10. The principal objective, synthesis of isocardenolide 11, was realized by selective reduction of ketone 5 with sodium borohydride in dimethylformamide.",

author = "George Pettit and Brian Green and {Das Gupta}, {Arun K.} and Whitehouse, {Philip A.} and Yardley, {John P.}",

year = "1970",

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doi = "10.1021/jo00830a027",

language = "English (US)",

volume = "35",

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T1 - Bufadienolides. 3. A Synthetic Route to Isocardenolides

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AU - Green, Brian

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AU - Whitehouse, Philip A.

AU - Yardley, John P.

PY - 1970/5/1

Y1 - 1970/5/1

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AB - A Bestmann reaction employing 3β-acetoxy-20-oxo-21-iodo-5-pregnene (2) and carbomethoxymethylenetriphenylphosphorane was used to complete a synthesis of methyl 3β-acetoxy-2-oxo-21-nor-5-imns-22-choladienate (1), which upon irradiation in sunlight gave cis isomer 5. Similarly, 3β-acetoxy-20-oxo-21-iodo-5,16-pregna-diene (6) was converted into trans side-chain olefin 7 and cis side-chain olefin 8. Palladium-catalyzed hydrogenation of triene 8 resulted in methyl 3-acetoxy-20-oxo-21-nor-5a-cholanate (9a) accompanied by small amounts of the corresponding 3-deoxy derivative 9b and 3β-acetoxy-20-hydroxy-21-nor-5a-cholanic acid γ-lactone (24 å 20). Subjecting triene 8 to sodium borohydride reduction in ethanol yielded isocardanolide 10. The principal objective, synthesis of isocardenolide 11, was realized by selective reduction of ketone 5 with sodium borohydride in dimethylformamide.

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Bufadienolides. 3. A Synthetic Route to Isocardenolides

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