C-24 Stereochemistry of Marine Sterols: (22E)-24-(Isopropenyl)-22-dehydrocholesterol and 24-Isopropenylcholesterol

Echigo, Shizue; Hara, Noriyuki; Carderon, Gladys Jeanette; Duque, Carmenza; Fujimoto, Yoshinori

doi:10.1248/cpb.54.1473

“…configuration. 473 Erylus placenta (Hachijo Is., Japan) yielded the steroidal glycosides sokodosides A 450 and B 451, which were found to be mildly cytotoxic to P388 cells and growth inhibitors of yeast. 474 The sponge Melophlus sarasinorum (Scott Reef, N. W. Australia) has yielded two further sarasinosides, A 4 452 and A 5 453.…”

Section: (+)-Cyanthiwiginmentioning

confidence: 99%

Marine natural products

Blunt

¹

,

Copp

²

,

Hu

³

et al. 2008

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This review covers the literature published in 2006 for marine natural products, with 758 citations (534 for the period January to December 2006) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, cnidaria, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds (779 for 2006), together with their relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.

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“…[9][10][11] We also utilized the orthoester Claisen rearrangement for the stereoselective synthesis of (24R)-and (24S)-(22E)-24-isopropenyl-22-dehydrocholesterol and 24-isopropenylcholesterol, another multiply alkylated sterol of T. ophiraphidites. 12 The synthetic route to 1a and 1b, and 2a and 2b is shown in Figure 2. The required starting materials, (22R)-allylic alcohol 3a and (22S)-allylic alcohol 3b, for the orthoester Claisen rearrangement were obtained stereoselectively from the corresponding enone [13][14][15] by reduction using DIBAL-H and L-selectride, respectively.…”

Section: Resultsmentioning

confidence: 99%

C-24 stereochemistry of marine Sterols: (22E)-24-Ethyl-24-methylcholesta-5,22-dien-3b-oβl and 24-Ethyl-24-methylcholest-5-en-3β-ol

Echigo

¹

,

Castellanos

²

,

Duque

³

et al. 2011

J. Braz. Chem. Soc.

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As configurações dos carbonos C-24 nos compostos (22E)-24-etil-24-metilcolesta-5,22-dien-3b-ol (1) e 24-etil-24-metilcolest-5-en-3b-ol (2), isolados da esponja do caribe colombiano Topsentia ophiraphidites foram determinadas como R e S, respectivamente, com base na comparação dos seus dados de RMN com aqueles de amostras de configurações já definidas 24R e 24S, as quais foram sintetizadas em rotas envolvendo ortoésteres provenientes do rearranjo de Claisen de álcoois D 23-22 alílicos. Este é primeiro estudo de síntese, em que o rearranjo de Claisen é utilizado para introduzir um centro quaternário em C-24, de maneira estereoespecífica e com rendimento aceitável. Análises por difração de raio X de 1 confirmaram essas atribuições estereoquímicas.The C-24 configurations of (22E)-24-ethyl-24-methylcholesta-5,22-dien-3b-ol (1) and 24-ethyl-24-methylcholest-5-en-3b-ol (2), isolated from the Colombian Caribbean sponge Topsentia ophiraphidites, were determined to be R and S, respectively, by comparing their NMR data with those of stereodefined (24R)-and (24S)-samples that were synthesized in routes involving the orthoester Claisen rearrangement of D 23 -22-allylic alcohols. This is the first synthetic study where the Claisen rearrangement is used to introduce a C-24 quaternary center in a stereospecific manner with acceptable yield. X-ray analysis of 1 confirmed these stereochemical assignments.

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Porifera (Sponges)–2

Kornprobst

¹

2014

Encyclopedia of Marine Natural Products

0

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The article contains sections titled: Secondary Metabolites of Hadromerida and Chondrosida Perforating Power of Clionaidae lyso ‐Phospholipids and Sulfated Sphingosines of Spirastrella abata Brominated Acetylenic Derivatives of Diplastrella Cyclic Peroxides Terpenes Unconventional Sterols Macrolactones: Latrunculins and Spongistatins Atypical Glycosides of Latrunculia corticata Other Nitrogen‐Free Toxins Peptides and Depsipeptides Pyrrole Derivatives and other Nitrogen‐Containing Heterocycles Atypical Nucleosides Secondary Metabolites of Lithistida Particular Characteristics of Lithistid Sponges Unusual Halogenated Fatty Acids Nitrogen‐Containing Sesquiterpenes of Theonella Specific Glycolipids of Theonella swinhoei, Discodermia calyx and D. dissoluta Long‐Chain Polyacetylenic Derivatives of Theonella sp 3β‐Methoxysterols of Jereicopsis graphidiophora 4‐Methylene Sterols and Sterones of Theonella Macrolides Examples of Acetogenins: Discodermolide, Calyculins, and Onnamides Linear Amides and Peptides Mono‐ and Bicyclic Peptides Symbiotic Origin of Some Polypeptides Cyclic and Linear Depsipeptides Atypical Nitrogenous Derivatives Secondary Metabolites of Spirophorida Atypical Sterols of Cinachyra, Microscleroderma , and Scleritoderma Cinachyrolide A, Enigmazole A Microsclerodermins and Aciculitins Examples of Atypical Derivatives of Some Sponges of the Tetillidae Secondary Metabolites of Agelasida Sterols Diterpenes and Carotenoids Gracilioethers of Agelas gracilis Merosesquiterpenes and Nitrogen‐Containing Meroditerpenes Galactosylceramides and Glycolipids Oroidin and Related C 11 N 5 Bromopyrrole Alkaloids Oroidin Series Agelastatin A Series Other Series Pyrrole‐2‐carboxylic Acid Derivatives Other Examples of Nitrogen‐Containing Heterocycles Betaines Secondary Metabolites of Halichondrida A‐ nor ‐Steroids and Other Nonconventional Sterols Conventional Terpenes Nitrogen‐Containing Terpenes: Isonitriles and Related Derivatives Other Terpenes Long‐Chain Linear Polyamines and α,ω‐bis‐isothiocyanates Polyethers: Halichondrins, Okadaic, and Glycookadaic Acids Various Lipids Linear Peptides of the Genera Auletta and Cymbastela Depsipeptides and Cyclic Peptides Unusual Amino Acids and Betaines Pyrrole, Imidazole, Pyridine, Isoquinoline, and Indole Derivatives Pyrrole Derivatives Imidazole Derivatives Pyridine and Isoquinoline Derivatives Indole Derivatives Heterocycles Related to the Oroidin Family Atypical Halogenated and Sulfur‐Containing Derivatives

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C-24 Stereochemistry of Marine Sterols: (22E)-24-(Isopropenyl)-22-dehydrocholesterol and 24-Isopropenylcholesterol

Cited by 7 publications

References 13 publications

Marine natural products

Marine natural products

C-24 stereochemistry of marine Sterols: (22E)-24-Ethyl-24-methylcholesta-5,22-dien-3b-oβl and 24-Ethyl-24-methylcholest-5-en-3β-ol

Porifera (Sponges)–2

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