Marine Sesquiterpene Research Articles

ChemInform Abstract: Biomimetic Synthesis of Theonellin Isocyanide.

A marine sesquiterpene of the theonellin class has been synthesized for the first time. Direct amination of the theonelline carbon framework 2 in a biometric fashion, a crucial step, was achieved by employing a triflic acid-promoted Ritter-type reaction at low temperature (–78 °C ).

Total Synthesis of 10-Isocyano-4-cadinene and Determination of Its Absolute Configuration

The first enantioselective total synthesis of 10-isocyano-4-cadinene, a marine sesquiterpene isolated from nudibranchs of the family Phyllidiidae, was achieved. The cadinene is expected to be a novel nontoxic antifouling agent. In the synthesis, an intermolecular Diels-Alder reaction and a SmI(2)-induced Barbier-type reaction were employed as key steps. The absolute configuration of 10-isocyano-4-cadinene was determined to be (1S, 6S, 7R, 10S) on the basis of the total synthesis. Antifouling activities against Balanus amphitrite with both enantiomers of 10-isocyano-4-cadinene were also evaluated.

The organocatalytic three-step total synthesis of (+)-frondosin B

The frondosins are a family of marine sesquiterpenes isolated from the sponge Dysidea frondosa that exhibit biological activities ranging from anti-inflammatory properties to potential application in anticancer and HIV therapy. Herein, a concise enantioselective total synthesis of (+)-frondosin B is described which requires a total of three chemical steps. The enantioselective conjugate addition of a benzofuran-derived boronic acid to crotonaldehyde in the presence of an imidazolidinone organocatalyst builds the critical stereogenic center of frondosin B in the first operation, while the remaining two ring systems of this natural product are installed in the two subsequent steps. A combination of X-ray crystallographic data, deuterium labeling, and chemical correlation studies provides further evidence as to the correct absolute stereochemical assignment of (+)-frondosin B.

Synthesis and biological activity of derivatives of the marine quinone avarone

Nine alkyl(aryl)thio derivatives of the marine sesquiterpene quinone avarone were synthesized by nucleophilic addition of thiols or thiophenol to avarone. In most cases only one regioisomer was obtained. Their cytotoxic activities, brine shrimp lethality and antibacterial activity were evaluated, as well as those of some previously synthesized avarone derivatives. Anti-HIV activity of two derivatives was tested. Electrochemical properties were determined for all the derivatives in order to obtain more accurate information on structure–activity relationships. Most derivatives showed cytotoxic activity against tumor cell lines, with IC 50 values less than 10 μM for some of them, in particular those with electron-donating substituents. The most active compound was 4′-(methylamino)avarone, with IC 50 value of 2.4 μM to melanoma Fem-X cells, and no cytotoxicity to normal lymphocytes.

Expeditious synthesis of helianane and C-10 halogenated heliananes employing ring-closing metathesis

An expeditious synthesis of the marine sesquiterpene helianane enclosing an unusual benzoxocane ring system is described employing ring-closing metathesis as the key step. Helianane has been further converted to the naturally occurring C-10 bromo and chloro derivatives.

Biotransformation of the marine sesquiterpene pacifenol by a facultative marine fungus

Continued investigation of the marine alga Laurencia claviformis has led to the isolation of pacifenol, a halogenated sesquiterpene as the major metabolite. The microbial transformation of pacifenol is reported. It was cultivated with a marine strain of Penicillium brevicompactum yielding a new compound. The structure was elucidated on the basis of spectroscopic data. The anti-microbial activity of pacifenol derivatives is reported.

Enantioselective First Total Syntheses of 2-(Formylamino)trachyopsane and ent-2-(Isocyano)trachyopsane via a Biomimetic Approach

A biomimetic rearrangement of an isotwistane to a tricyclo[4.3.1.0(3,8)]decane has been employed as the key step for the enantioselective first total syntheses of the marine sesquiterpenes 2-(formylamino)trachyopsane and ent-2-(isocyano)trachyopsanes ascertaining the biogenetic relationship between the marine sesquiterpenes neopupukeananes and trachyopsanes.

Laurencia okamuraiExtract Containing Laurinterol Induces Apoptosis in Melanoma Cells

Laurinterol is a marine sesquiterpene that has been known to have antimicrobial activity. The purpose of this study is to investigate the effect of Laurencia okamurai extract containing laurinterol (LOEL) on induction of apoptosis in melanoma cells (B16F1). Anticancer activity of LOEL against melanoma cells was shown in a dose-dependent manner by the 1-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay. It was for the first time found that LOEL exhibited an excellent effect on the induction of apoptosis as determined by DNA fragmentation, terminal deoxynucleotidyl transferase-mediated dUTP in situ nick-end labeling assay, cell cycle analysis, and measurement of activities of several caspases in melanoma cells. It was also demonstrated that transcriptional activation of p53, a tumor suppressor gene, and activation of p21 promoter by LOEL were involved in the induction of apoptosis by reporter gene assay. In particular, western blot analysis confirmed that LOEL above 5 microg/mL significantly increased the expression level of phospho-p53, the active form. These results indicate that LOEL can induce apoptosis through a p53-dependent pathway in melanoma cells.

Chemical transformation and biological studies of marine sesquiterpene ( S)-(+)-curcuphenol and its analogs

Chemical transformation studies of the marine sesquiterpene phenol ( S)-(+)-curcuphenol ( 1), isolated from the Jamaican sponges Myrmekioderma styx, were accomplished. In order to optimize the activity and better understand the SAR of ( S)-(+)-curcuphenol, nineteen semisynthetic analogs were prepared and evaluated for activity against infectious diseases. A number of analogs showed significant activity against Mtb and Leishmania donovani, while showed good to moderate activities in antibacterial and antifungal assays as well as against Plasmodium falciparium (D6 clone) and (W2 clone). The analogs a, c, h, and r exhibited Mtb activity with MICs of 24.6, 41.2, 6.90, and 50.5 μM, respectively. Analog f showed enhanced activity against L. donovani with an IC 50 of 0.6 μM and IC 90 of 40 μM respectively.

Reactivity and Biological Activity of the Marine Sesquiterpene Hydroquinone Avarol and Related Compounds from Sponges of the Order Dictyoceratida

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Reactivity and Biological Activity of the Marine Sesquiterpene Hydroquinone Avarol and Related Compounds from Sponges of the Order Dictyoceratida

A review of results of bioactivity and reactivity examinations of marine sesquiterpene (hydro)quinones is presented. The article is focused mostly on friedo- rearranged drimane structural types, isolated from sponges of the order Dictyoceratida. Examples of structural correlations are outlined. Available results on the mechanism of redox processes and examinations of chemo- and regioselectivity in addition reactions are presented and, where possible, analyzed in relation to established bioactivities. Most of the bioactivity examinations are concerned with antitumor activities and the mechanism thereof, such as DNA damage, arylation of nucleophiles, tubulin assembly inhibition, protein kinase inhibition, inhibition of the arachidonic cascade, etc. Perspectives on marine drug development are discussed with respect to biotechnological methods and synthesis. Examples of the recognition of validated core structures and synthesis of structurally simplified compounds retaining modes of activity are analyzed.

Bargellini condensation of coumarins. Expeditious synthesis of o-carboxyvinylphenoxyisobutyric acids

Condensation of coumarins with chloroform and acetone in the presence of a base furnished o-carboxyvinylphenoxyisobutyric acids in good yields. The diacid 7a was transformed in a few high yielding steps to the marine sesquiterpene helianane underscoring the importance of this new protocol.

A formal total synthesis of (±)-9-isocyanoneopupukeanane

A formal total synthesis of the marine sesquiterpene (±)-9-isocyanoneopupukeanane starting from the readily available monoterpene carvone has been accomplished employing a combination of intermolecular Michael addition–intramolecular Michael addition reaction and an intramolecular rhodium carbenoid C–H insertion reaction as key steps, and identifying the isopropenyl group as a masked hydroxy group.

Synthesis of Helianane (V), an Unusual Marine Sesquiterpene Employing Ring‐Expansion by Flash Vacuum Thermolysis.

ChemInformVolume 36, Issue 15 Natural Products Synthesis of Helianane (V), an Unusual Marine Sesquiterpene Employing Ring-Expansion by Flash Vacuum Thermolysis. Subir K. Sabui, Subir K. Sabui Dep. Org. Chem., Indian Assoc. Cultiv. Sci., Jadavpur, Calcutta 700 032, IndiaSearch for more papers by this authorRamanathapuram V. Venkateswaran, Ramanathapuram V. Venkateswaran Dep. Org. Chem., Indian Assoc. Cultiv. Sci., Jadavpur, Calcutta 700 032, IndiaSearch for more papers by this author Subir K. Sabui, Subir K. Sabui Dep. Org. Chem., Indian Assoc. Cultiv. Sci., Jadavpur, Calcutta 700 032, IndiaSearch for more papers by this authorRamanathapuram V. Venkateswaran, Ramanathapuram V. Venkateswaran Dep. Org. Chem., Indian Assoc. Cultiv. Sci., Jadavpur, Calcutta 700 032, IndiaSearch for more papers by this author First published: 15 March 2005 https://doi.org/10.1002/chin.200515173Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume36, Issue15April 12, 2005 RelatedInformation

Synthesis of helianane, an unusual marine sesquiterpene employing ring-expansion by flash vacuum thermolysis

A total synthesis of the marine sesquiterpene helianane 1 is described involving the thermal rearrangement of the benzoxabicyclo[4.2.0]octenone 4 to generate the dienone 5 incorporating the benzoxocane ring system of 1 . This dienone was converted to the key ketone 11 , which on interaction with methylmagnesium iodide followed by hydrogenation of the resulting alkene 18 furnished helianane 1 .

Carbanion cyclisation of esters. Part 2: Enantiospecific construction of the tricyclic framework of the marine sesquiterpenes, spirodysins

Enantiospecific construction of the bicyclo[4.3.0]nonan-8-one 17 employing a lithium and liquid ammonia mediated carbanion cyclisation of the δ-methyl-δ,ε-unsaturated ester 13, and its elaboration to the tricyclic framework of the marine sesquiterpenes spirodysins are described.

Total Synthesis of the Marine Sesquiterpene Quinones Hyatellaquinone and Spongiaquinone

AbstractThe synthesis of the marine sesquiterpene quinone (+)‐hyatellaquinone (1) was achieved starting from the sesquiterpene aldehyde (+)‐albicanal ((+)‐3) (Schemes 3 and 4). Coupling of (+)‐albicanal with 2,3,5,6‐tetramethoxyphenyllithium led to the aryl‐sesquiterpene system, which was modified to the target molecule. Furthermore, the first total synthesis of the marine compound spongiaquinone (2) was carried out starting from ((−)‐albicanal (−)‐3) in a reaction sequence encompassing a stereoselective CC bond hydrogenation and a one‐pot AcOH elimination/demethylation reaction (Schemes 7 and 10). The occurrence of 1,2‐ and 1,4‐benzoquinone forms of 1 and 2 depends on the pH of the solvent system.

Stereochemistry of the Marine Sesquiterpene 2‐Thiocyanatoneopupukeanane: Crystal Structure of Neopupukean‐2‐yl 4‐Nitrobenzoate.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis and Antifouling Activity of 3‐Isocyanotheonellin and Its Analogues.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Enantiospecific synthesis of the antituberculosis marine sponge metabolite (+)-puupehenone. The arenol oxidative activation route.

[formula: see text] The total synthesis of the marine sesquiterpene quinone (+)-puupehenone, a promising new antituberculosis agent, was achieved in 10 steps starting from commercially available (+)-sclareolide. The key feature of this synthesis is the construction of the heterocycle via an intramolecular attack of the terpenoid-derived C-8 oxygen function onto an oxidatively activated 1,2-dihydroxyphenyl unit.