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Crisostomo F.P.,CSIC - Institute of Natural Products and Agrobiology | Martin T.,CSIC - Institute of Natural Products and Agrobiology | Martin T.,University of La Laguna | Carrillo R.,CSIC - Institute of Natural Products and Agrobiology | Carrillo R.,University of La Laguna
Angewandte Chemie - International Edition | Year: 2014

Ascorbic acid (vitaminC) has been used as a radical initiator in a metal-free direct C-H arylation of (hetero)arenes. Starting from an aniline, the corresponding arenediazonium ion is generated in situ and immediately reduced by vitaminC to an aryl radical that undergoes a homolytic aromatic substitution with a (hetero)arene. Notably, neither heating nor irradiation is required. This procedure is mild, operationally simple, and constitutes a greener approach to arylation. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Emerson B.C.,CSIC - Institute of Natural Products and Agrobiology | Faria C.M.A.,University of East Anglia
Molecular Ecology | Year: 2014

A well-used metaphor for oceanic islands is that they act as 'natural laboratories' for the study of evolution. But how can islands or archipelagos be considered analogues of laboratories for understanding the evolutionary process itself? It is not necessarily the case that just because two or more related species occur on an island or archipelago, somehow, this can help us understand more about their evolutionary history. But in some cases, it can. In this issue of Molecular Ecology, Garrick et al. (2014) use population-level sampling within closely related taxa of Galapagos giant tortoises to reveal a complex demographic history of the species Chelonoidis becki - a species endemic to Isabela Island, and geographically restricted to Wolf Volcano. Using microsatellite genotyping and mitochondrial DNA sequencing, they provide a strong case for C. becki being derived from C. darwini from the neighbouring island of Santiago. But the interest here is that colonization did not happen only once. Garrick et al. (2014) reveal C. becki to be the product of a double colonization event, and their data reveal these two founding lineages to be now fusing back into one. Their results are compelling and add to a limited literature describing the evolutionary consequences of double colonization events. Here, we look at the broader implications of the findings of Garrick et al. (2014) and suggest genomic admixture among multiple founding populations may be a characteristic feature within insular taxa. © 2014 John Wiley & Sons Ltd.

Tzedakis P.C.,University College London | Emerson B.C.,CSIC - Institute of Natural Products and Agrobiology | Emerson B.C.,University of East Anglia | Hewitt G.M.,University of East Anglia
Trends in Ecology and Evolution | Year: 2013

Here, we examine the evidence for tree refugia in northern Europe during the Late Pleniglacial (LPG) interval of maximum tree-range contraction. Our review highlights the often equivocal nature of genetic data and a tendency to overestimate potential tree distributions due to warm climate-model bias, and also reveals a convergence of macrofossil and pollen evidence. What emerges is the absence of temperate trees north of 45°N and a west-east (W-E) asymmetry in boreal tree distribution, with a treeless Western Europe north of 46°N, while restricted boreal populations persisted in Eastern Europe up to 49°N, and higher latitudes east of the Fennoscandian ice-sheet. These results have implications for current thinking on European genetic diversity patterns, species migration capacity, and conservation strategies. © 2013 Elsevier Ltd.

Hernandez D.,CSIC - Institute of Natural Products and Agrobiology | Boto A.,CSIC - Institute of Natural Products and Agrobiology
European Journal of Organic Chemistry | Year: 2014

The azanucleosides are nucleoside analogues where the furanose ring is replaced by a nitrogen-containing ring or chain. Many azanucleosides are potent antiviral, anticancer and antimicrobial agents, or serve as valuable components of oligonucleotides with improved stability, binding or hybridization properties. Therefore, the development of new analogues is a very active area in medicinal and synthetic chemistry. Their synthesis and their interesting biological properties are discussed in this microreview. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gonzalez-Castro A.,CSIC - Institute of Natural Products and Agrobiology | Traveset A.,CSIC - Mediterranean Institute for Advanced Studies | Nogales M.,CSIC - Institute of Natural Products and Agrobiology
Journal of Biogeography | Year: 2012

Aim We studied, for the first time, the effect of insularity on plant-seed disperser networks at both the community and species level. We focused on the Mediterranean shrubland, comparing different biogeographical scenarios (insular and continental) that share the same basic species composition. Location The study was conducted within one mainland (southern Spain) and four island localities: two in the Canary Islands (oceanic origin) and two in the Balearic Islands (continental origin). Methods We built qualitative (presence/absence of interaction) and quantitative seed dispersal networks (number of consumed fruits) and used different descriptor parameters, such as connectance, nestedness, interaction asymmetry and various interaction diversity indices that describe their topology. To assemble the interaction networks, we used data on the presence of different species of fruits in systematically collected droppings of the different seed dispersers; seeds in droppings were identified by means of a binocular lens whereas a microscope was used to identify pericarp tissue remains. Results Island networks were smaller and less complex (a lower number of observed links than expected for their size) than the mainland network. As expected, connectance was higher within islands than on the mainland. By contrast, nestedness was consistently high at all sites, although relative nestedness (which accounts for network size) was lower within islands, whether continental or oceanic. At both community and species level (especially for animals) interactions tended to be more specialized and symmetric within the islands. Main conclusions The lower species number and greater specialization in insular seed dispersal systems appears to lead to the prevalence of more symmetric interactions than those found on the mainland. This indicates that insular mutualistic interactions and interacting species are more vulnerable than mainland ones to disturbances, as previous work has suggested that asymmetrical interactions facilitate the maintenance of biodiversity and act as a resilience mechanism against species extinction. © 2012 Blackwell Publishing Ltd.

Boto A.,CSIC - Institute of Natural Products and Agrobiology | Romero-Estudillo I.,CSIC - Institute of Natural Products and Agrobiology
Organic Letters | Year: 2011

Common β-hydroxy amino acids (such as threonine) can be readily transformed into 1,2-amino alcohols with excellent stereoselectivity. This one-pot decarboxylation-alkylation process allows the replacement of the carboxyl group by alkyl, allyl, or aryl groups, generally in high yields. A variation of the process (decarboxylation-Diels-Alder) allows the formation of bi- and polycyclic systems, which are useful precursors of alkaloid cores or iminosugars. © 2011 American Chemical Society.

Tejedor D.,CSIC - Institute of Natural Products and Agrobiology | Mendez-Abt G.,CSIC - Institute of Natural Products and Agrobiology | Cotos L.,CSIC - Institute of Natural Products and Agrobiology | Garcia-Tellado F.,CSIC - Institute of Natural Products and Agrobiology
Chemical Society Reviews | Year: 2013

The propargyl Claisen rearrangement is a known protocol to gain access to functionalized allenes through the [3,3]-sigmatropic transformation of propargyl vinyl ethers. The correct use of appropriate propargyl vinyl ethers as starting materials coupled with suitable reaction conditions can aid in the development of new domino methodologies in which the allenes are valuable intermediates in route to a wide range of important classes of organic compounds. © The Royal Society of Chemistry 2013.

Hernandez-Guerra D.,CSIC - Institute of Natural Products and Agrobiology | Rodriguez M.S.,CSIC - Institute of Natural Products and Agrobiology | Suarez E.,CSIC - Institute of Natural Products and Agrobiology
Organic Letters | Year: 2013

A new general methodology for the synthesis of chiral vinylphosphonate and vinylphosphine oxide carbohydrate derivatives has been developed using the anomeric alkoxyl radical fragmentation reaction as the key step. The synthetic sequence proceeded via β-iodophosphonate and β-iodophosphine oxide intermediates, which may be interesting synthons for the introduction of phosphorus into organic molecules. These vinylphosphonates could be easily transformed into 2-methylene-1-phosphapentofuranoses (3-methylene-1,2- oxaphospholanes) and β-aminophosphonates, isosteres of biologically active α-methylene-γ-lactones and β-amino acids, respectively. © 2013 American Chemical Society.

Fraga B.M.,CSIC - Institute of Natural Products and Agrobiology
Natural Product Reports | Year: 2013

Covering: 2012. Previous review: Nat. Prod. Rep. 2012, 29, 1334. This review covers the isolation, structural determination, synthesis and chemical and microbiological transformations of natural sesquiterpenoids. The literature from January to December 2012 is reviewed, and 471 references are cited. © 2013 The Royal Society of Chemistry.

Fraga B.M.,CSIC - Institute of Natural Products and Agrobiology
Phytochemistry | Year: 2012

The phytochemical content of the Mediterranean species of the Sideritis genus has been reviewed. The components included in this review are monoterpenes, sesquiterpenes, diterpenes, triterpenes, sterols, flavones, coumarins and phenylpropanoids. From the chemotaxonomic point of view, we have divided the species from this region into four groups. The first of this is formed by taxa containing triterpenes, but not diterpenes. A second group is constituted by species having bicyclic diterpenes of the labdane type and not diterpenes. The third group is characterized by its content in tetracyclic diterpenes of the ent-kaurene type. A fourth group is composed of plants with tetracyclic diterpenes of the ent-beyer-15-ene and/or ent-atis-13-ene class. In addition, the relations of these Mediterranean species with those of the Macaronesian region have been examined. © 2011 Elsevier Ltd. All rights reserved.

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