Conversion of ruscogenin into 1α- and 1β hydroxycholesterol derivatives

Noam, M.; Tamir, Ilana; Breuer, Eli; Mechoulam, Raphael

doi:10.1016/s0040-4020(01)92435-4

Cited by 15 publications

(9 citation statements)

References 16 publications

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“…This procedure was modified from the published conditions because the use of LiBr instead of LiCl resulted in a mixture of C19 chlorinated and brominated product. Reduction of the A-ring ketone using NaBH 4 afforded alcohol 11 in 85% yield as a single diastereomer, in agreement with the observations of Mechoulam for similar steroidal systems …”

supporting

confidence: 89%

“…Reduction of the A-ring ketone using NaBH 4 afforded alcohol 11 in 85% yield as a single diastereomer, in agreement with the observations of Mechoulam for similar steroidal systems. 13 …”

mentioning

confidence: 99%

“…Reduction of the A-ring ketone using NaBH 4 afforded alcohol 11 in 85% yield as a single diastereomer, in agreement with the observations of Mechoulam for similar steroidal systems. 13 Dehydration of the alcohol to form alkene 5 proved problematic because formation of the intermediate triflate using either Tf 2 O/Et 3 N or PhNTf 2 /LDA resulted in complex mixtures, with isolated yields of desired product ranging between 10 and 50%. Attempts to form the mesylate or tosylate under a variety of conditions were unsuccessful under a variety of conditions, presumably because of the sterically encumbered nature of the alcohol.…”

mentioning

confidence: 99%

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A Synthesis of the ABC Tricyclic Core of the Clionastatins Serves To Corroborate Their Proposed Structures

Tartakoff

Vanderwal

2014

Org. Lett.

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A synthesis of the ABC tricyclic ring system of the clionastatins, an unusual pair of highly chlorinated androstane steroids, has been accomplished. This work provides strong support for the original structural proposal. An unexpected substrate-dependent reversal in alkene chlorination diastereoselectivity was critical to success. This approach should be amenable to an eventual enantioselective synthesis of the natural products themselves.

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supporting

confidence: 89%

“…Reduction of the A-ring ketone using NaBH 4 afforded alcohol 11 in 85% yield as a single diastereomer, in agreement with the observations of Mechoulam for similar steroidal systems. 13 …”

mentioning

confidence: 99%

mentioning

confidence: 99%

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A Synthesis of the ABC Tricyclic Core of the Clionastatins Serves To Corroborate Their Proposed Structures

Tartakoff

Vanderwal

2014

Org. Lett.

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“…Diosgenin was used commercially to produce steroid hormones such as cortisone, estrogen, and progesterone by in vitro chemical modification [ 7 ]. 1α-Hydroxydiosgenin and 1β-hydroxydiosgenin (ruscogenin) were used as starting materials in the synthesis of 1α-hydroxycholesterol and 1β-hydroxycholesterol by chemical removal of its side chain [ 8 , 9 ]. The study showed that 1β-hydroxydiosgenin could be used as a potential starting material for 1α- or 1β-hydroxy vitamin D analogs [ 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

Epoxidation of Diosgenin, 25(R)-1,4,6-Spirostatrien-3-one and 25(R)-4,6-Spirostadien-3β-ol

Kim

2003

Molecules

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Upon treatment of 25(R)-spirost-5-en-3β-ol (diosgenin), 25(R)-1,4,6-spirostatrien-3-one and 25(R)-4,6-spirostadien-3β-ol with 30% H2O2 and 5% NaOH in methanol, diosgenin did not react, 25(R)-1,4,6-spirostatrien-3-one was converted to 25(R)-1α,2α-epoxy-4,6-spirostadien-3-one and 25(R)-4,6-spirostadien-3β-ol was oxidized to give a small amount of 25(R)-4,6-spirostadien-3-one, while most of the original starting material remained unchanged. On the other hand, reactions of diosgenin, 25(R)-1,4,6-spirostatrien-3-one and 25(R)-4,6-spirostadien-3β-ol with m-chloroperoxy-benzoic acid in chloroform yielded 25(R)-5α,6α-epoxyspirostan-3β-ol, 25(R)-6α,7α-epoxy-1,4-spirostadien-3-one and 25(R)-4β,5β-epoxy-6-spirosten-3β-ol, respectively.

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“…26-Hydroxycholesterol 21 was chosen as the starting material since it had been previously prepared by Clemmensen reduction of diosgenin 19 followed by C-16 deoxygenation of the resulting 3α,16β,26-triol 20 (10). Selective silylation of 21 at C-26 followed by Oppenauer oxidation of the C-3 alcohol in 22 and acetylation of the desilylated C-26 alcohol afforded the enone acetate 23.…”

mentioning

confidence: 99%

Isolation and synthesis of shark‐repelling saponins

Williams

Gong

2004

Lipids

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Saponins are complex compounds that are composed of a saccharide attached to a steroid or triterpene. They are natural surfactants, or detergents. Several important biological effects have been ascribed to saponins. They have been isolated from a great number of terrestrial plants. In the animal kingdom they are found in most sea cucumbers and starfish, whereas they are found only rarely in alcyonarians, gorgonians, sponges, and as shark-repelling compounds in fish. The present review deals with the isolation and some syntheses of the shark-repelling saponins mosesins-1 to -5 and pavoninins-1 to -6 obtained from the fish species Pardachirus.

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Conversion of ruscogenin into 1α- and 1β hydroxycholesterol derivatives

Cited by 15 publications

References 16 publications

A Synthesis of the ABC Tricyclic Core of the Clionastatins Serves To Corroborate Their Proposed Structures

A Synthesis of the ABC Tricyclic Core of the Clionastatins Serves To Corroborate Their Proposed Structures

Epoxidation of Diosgenin, 25(R)-1,4,6-Spirostatrien-3-one and 25(R)-4,6-Spirostadien-3β-ol

Isolation and synthesis of shark‐repelling saponins

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