Three new sesquiterpenoids from the marine alga .

González, Antonio G.; Aguiar, Juan M.; Martı́n, Julio D.; Norte, Manuel

doi:10.1016/0040-4039(75)80049-9

Cited by 50 publications

(16 citation statements)

References 13 publications

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“…The acetogenins (3Z)-laurenyne (798) and (À)-(3E,6R,7R)-pinnatifidenyne (ent-812) showed antifeedant activity against C. auratus at 50 μg/cm 2 concentrations, while brasilenol (398), (E)-pinnatifidenyne (814), (+)-(3E, 6R,7R)-obtusenyne (ent-895), and (+)-(3Z,6R,7R)-obtusenyne (ent-896) were inactive [407].…”

Section: Antifeedant Activity and Toxicity To Marine Organismsmentioning

confidence: 99%

The Laurencia Paradox: An Endless Source of Chemodiversity

Harizani

Iοannou

Roussis

2016

Progress in the Chemistry of Organic Natural Products

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Nature, the most prolific source of biological and chemical diversity, has provided mankind with treatments for health problems since ancient times and continues to be the most promising reservoir of bioactive chemicals for the development of modern drugs. In addition to the terrestrial organisms that still remain a promising source of new bioactive metabolites, the marine environment, covering approximately 70% of the Earth's surface and containing a largely unexplored biodiversity, offers an enormous resource for the discovery of novel compounds. According to the MarinLit database, more than 27,000 metabolites from marine macro- and microorganisms have been isolated to date providing material and key structures for the development of new products in the pharmaceutical, food, cosmeceutical, chemical, and agrochemical sectors. Algae, which thrive in the euphotic zone, were among the first marine organisms that were investigated as sources of food, nutritional supplements, soil fertilizers, and bioactive metabolites.Red algae of the genus Laurencia are accepted unanimously as one of the richest sources of new secondary metabolites. Their cosmopolitan distribution, along with the chemical variation influenced to a significant degree by environmental and genetic factors, have resulted in an endless parade of metabolites, often featuring multiple halogenation sites.The present contribution, covering the literature until August 2015, offers a comprehensive view of the chemical wealth and the taxonomic problems currently impeding chemical and biological investigations of the genus Laurencia. Since mollusks feeding on Laurencia are, in many cases, bioaccumulating, and utilize algal metabolites as chemical weaponry against natural enemies, metabolites of postulated dietary origin of sea hares that feed on Laurencia species are also included in the present review. Altogether, 1047 secondary metabolites, often featuring new carbocyclic skeletons, have been included.The chapter addresses: (1) the "Laurencia complex", the botanical description and the growth and population dynamics of the genus, as well as its chemical diversity and ecological relations; (2) the secondary metabolites, which are organized according to their chemical structures and are classified into sesquiterpenes, diterpenes, triterpenes, acetogenins, indoles, aromatic compounds, steroids, and miscellaneous compounds, as well as their sources of isolation which are depicted in tabulated form, and (3) the biological activity organized according to the biological target and the ecological functions of Laurencia metabolites.

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Section: Antifeedant Activity and Toxicity To Marine Organismsmentioning

confidence: 99%

The Laurencia Paradox: An Endless Source of Chemodiversity

Harizani

Iοannou

Roussis

2016

Progress in the Chemistry of Organic Natural Products

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“…In the biological evaluation for 60-62, no significant bioactivities were found (Wright et al 2003;Iliopoulou et al 2002). Although the number was higher than that of halogenated perforanes (Wang et al 2013), the biosynthesis of this backbone was speculated from a C-10 brominated chamigrane intermediate (González et al 1975). Snyderanes and cyclic/rearranged synderanes This class was represented by eight members (65-72) from five Laurencia species.…”

Section: Perforanesmentioning

confidence: 99%

“…On the other hand, some nonhalogenated products might be derived from the simple dehalogenation of their halogenated analogues, such as the nonhalogenated chamigrane and cuparane sesquiterpenes. Additionally, the dehalogenation process might be followed by cyclization and rearrangement to result in the transformation of some skeletons (González et al 1975), exemplified by laurane, perforane, cyclolaurane, rearranged snyderane, etc. For some oxygenated nonhalogenated triterpenes and C 15 -acetogenins, they might be derived from the same precursors as their halogenated analogues through the key 1,2-epoxy intermediates (Fernández et al 2000;Abdel-Mageed et al 2010).…”

Section: Miscellaneous Nonhalogenated Productsmentioning

confidence: 99%

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Nonhalogenated organic molecules from Laurencia algae

Wang

2013

Phytochem Rev

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The marine red algae of the genus Laurencia have produced more 700 secondary metabolites and exhibited high molecular diversity and intriguing bioactivity. Since the halogenated structures have been comprehensively reviewed previously, this review, covering up to the end of 2012, mainly focuses on the source, structure elucidation, and bioactivity of nonhalogenated organic molecules from Laurencia spp. as well as the relationship between nonhalogenated and halogenated products. Overall, 173 new or new naturally occurring compounds with 58 skeletons, mainly including sesquiterpenes, diterpenes, triterpenes, and C 15 -acetogenins, are described.

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“…in himachalane and perforene sesquiterpenes such as α-himachalene [4] and perforenone A and B [5]. Of particular medicinal interest are the daphnane and tigliane derivatives, some of which can act as tumor promoters [6].…”

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confidence: 99%

Intramolecular Diels-Alder reactions. 5 [1] Facile synthesis of an octahydrobenzocycloheptenone derivative utilising intramolecular Diels-Alder reaction

Frey

Reißig

1999

J. prakt. Chem.

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173Carbocyclic molecules containing fused six-and seven-membered rings are found in a number of natural products [3], e.g. in himachalane and perforene sesquiterpenes such as α-himachalene [4] and perforenone A and B [5]. Of particular medicinal interest are the daphnane and tigliane derivatives, some of which can act as tumor promoters [6]. A number of syntheses of such fused 6/7 bicyclic ring systems [7] involved an IMDA reaction as the key step. Abstract. Undecatrienone 4 was prepared in a short sequence via siloxycyclopropanes 1 and 3. Intramolecular Diels-Alder reaction (IMDA) of 4 under various conditions afforded octahydrobenzocycloheptenone derivative 5 as a mixture of three or four diastereomers. High diastereoselectivities in favour of the endo-product cis-5a could be obbe achieved by choice of the appropriate Lewis acid promoter [8c]. The use of strong Lewis acids with two free coordination sites led to the formation of the otherwise unfavoured trans-fused cycloadducts via a novel chelate-controlled cycloaddition reaction. The transfused octalone products, that were now available in good yields for the first time, were elaborated to the sesquiterpene α-eudesmol [8c], and, in a formal total synthesis, to the pharmaceutically important compound dihydromevinolin [1]. Here, we report the extension of the siloxycyclopropane route developed in our laboratory to undecatrienone substrates, and an IMDA reaction to furnish a fused 6/7 ring system. Since these syntheses were performed with racemates, all chiral compounds are provided as mixtures of both enantiomers; for clarity, only one enantiomer is depicted in the schemes. IntramolecularOur approach to the undecatrienone substrate starts with the literature-known siloxycyclopropane 1 [9]. Deprotonation of 1 with LDA and subsequent reaction with E-1-iodo-3,5-hexadiene (2) [10] in presence of the lithium complexing agent 1,3-dimethylimidazolidin-2-one (DMEU) furnished the tetrasubstituted cyclopropane 3 in 44% yield with recovery of some starting material 1. The modest yield of this reaction could not be explained in terms of low reactivity of the iodide 2 since analogous alkylation reactions with saturated iodides [11] generally proceed very smoothly (70-90% yield). It was found, however, that the yield was considerably lower (61%) when 1-iodo-3-butene was employed [12]. We therefore attribute the lower yields of the alkylation reactions with homoallylic iodides to the competing elimination reaction with either excess of LDA or the ester enolate acting as base. Due to the volatility and tendentained with TiCl 4 as promoter. This selectivities were attributed to the formation of a seven-membered ring chelate as intermediate. The configurational assignment of all four diastereomers of 5 was based on isomerisation reactions and NMR analysis.We recently described syntheses and IMDA reactions of variably substituted 1,7,9-decatrien-3-ones to octahydronaphthalenones [1, 8]. The trienone substrates were assembled in fast and efficient sequences from simple precursors ...

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Three new sesquiterpenoids from the marine alga .

Cited by 50 publications

References 13 publications

The Laurencia Paradox: An Endless Source of Chemodiversity

The Laurencia Paradox: An Endless Source of Chemodiversity

Nonhalogenated organic molecules from Laurencia algae

Intramolecular Diels-Alder reactions. 5 [1] Facile synthesis of an octahydrobenzocycloheptenone derivative utilising intramolecular Diels-Alder reaction

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