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Abstract The rise of CO 2 in atmosphere is considered as the major reason for global warming. Therefore, CO 2 utilization has attracted more and more attention. Among those, using CO 2 as C1-feedstock for the chemical industry provides a solution. Here we show a two-step cascade process to perform catalytic carbonylations of olefins, alkynes, and aryl halides utilizing CO 2 and H 2 . For the first step, a novel heterogeneous copper 10Cu@SiO 2 -PHM catalyst exhibits high selectivity (≥98%) and decent conversion (27%) in generating CO from reducing CO 2 with H 2 . The generated CO is directly utilized without further purification in industrially important carbonylation reactions: hydroformylation, alkoxycarbonylation, and aminocarbonylation. Notably, various aldehydes, (unsaturated) esters and amides are obtained in high yields and chemo-/regio-selectivities at low temperature under ambient pressure. Our approach is of interest for continuous syntheses in drug discovery and organic synthesis to produce building blocks on reasonable scale utilizing CO 2 .

Isocyanides have long been known as versatile chemical reagents in organic synthesis. Their ambivalent nature also allows them to function as a CO-substitute in palladium-catalyzed cross couplings. Over the past decades, isocyanides have emerged as practical and versatile C building blocks, whose inherent -substitution allows for the rapid incorporation of nitrogeneous fragments in a wide variety of products. Recent developments in palladium catalyzed isocyanide insertion reactions have significantly expanded the scope and applicability of these imidoylative cross-couplings. This review highlights the advances made in this field over the past eight years.

The (site-selective) derivatization of amino acids and peptides represents an attractive field with potential applications in the establishment of structure-activity relationships and labeling of bioactive compounds. In this respect, bioorthogonal cross-coupling reactions provide valuable means for ready access to peptide analogues with diversified structure and function. Due to the complex and chiral nature of peptides, mild reaction conditions are preferred; hence, a suitable cross-coupling reaction is required for the chemical modification of these challenging substrates. The Suzuki reaction, involving organoboron species, is appropriate given the stability and environmentally benign nature of these reactants and their amenability to be applied in (partial) aqueous reaction conditions, an expected requirement upon the derivatization of peptides. Concerning the halogenated reaction partner, residues bearing halogen moieties can either be introduced directly as halogenated amino acids during solid-phase peptide synthesis (SPPS) or genetically encoded into larger proteins. A reversed approach building in boron in the peptidic backbone is also possible. Furthermore, based on this complementarity, cyclic peptides can be prepared by halogenation, and borylation of two amino acid side chains present within the same peptidic substrate. Here, the Suzuki-Miyaura reaction is a tool to induce the desired cyclization. In this review, we discuss diverse amino acid and peptide-based applications explored by means of this extremely versatile cross-coupling reaction. With the advent of peptide-based drugs, versatile bioorthogonal conversions on these substrates have become highly valuable.

The methylene group of various substituted 2- and 4-benzylpyridines, benzyldiazines and benzyl(iso)quinolines was successfully oxidized to the corresponding benzylic ketones using a copper or iron catalyst and molecular oxygen as the stoichiometric oxidant. Application of the protocol in API synthesis is exemplified by the alternative synthesis of a precursor to the antimalarial drug Mefloquine. The oxidation method can also be used to prepare metabolites of APIs which is illustrated for the natural product papaverine. ICP-MS analysis of the purified reaction products revealed that the base metal impurity was well below the regulatory limit.

Spin traps, like 5,5-dimethyl-1-pyrroline N -oxide (DMPO), are commonly used to identify radicals formed in numerous chemical and biological systems, many of which contain metal-ion complexes. In this study, continuous wave electron paramagnetic resonance and hyperfine spectroscopy are used to prove the equatorial ligation of DMPO(-derived) molecules to Cu(II), even in the presence of competing nitrogen bases. The experimental data are corroborated with density functional theory calculations. It is shown that 14 N HYSCORE can be used as a fingerprint method to reveal the coordination of DMPO(-derived) molecules to Cu(II), an interaction that might influence the outcome of spin-trapping experiments and consequently the conclusion drawn on the mechanism under study.

Ergot alkaloids are mycotoxins produced by fungi of the genus Claviceps, which infect cereal crops and grasses. The uptake of ergot alkaloid contaminated cereal products can be lethal to humans and animals. For food safety assessment, analytical techniques are currently used to determine the presence of ergot alkaloids in food and feed samples. However, the number of samples which can be analyzed is limited, due to the cost of the equipment and the need for skilled personnel. In order to compensate for the lack of rapid tests for the detection of ergot alkaloids, the aim of this study was to develop a specific recognition element for ergot alkaloids, which could be further applied to produce a colorimetric reaction in the presence of these toxins. As recognition elements, single-stranded DNA ligands were selected by using an iterative selection procedure named SELEX, i.e., Systematic Evolution of Ligands by EXponential enrichment. After several selection cycles, the resulting aptamers were cloned and sequenced. A surface plasmon resonance analysis enabled determination of the dissociation constants of the complexes of aptamers and lysergamine. Dissociation constants in the nanomolar range were obtained with three selected aptamers. One of the selected aptamers, having a dissociation constant of 44 nM, was linked to gold nanoparticles and it was possible to produce a colorimetric reaction in the presence of lysergamine. This system could also be applied to small ergot alkaloids in an ergot contaminated flour sample.

Urban trees form a vital component of sustainable cities but the use of a restricted range of species and genotypes may pose a risk to global biodiversity. Despite several studies investigating tree species diversity, intraspecific genetic diversity of urban trees remains largely unexplored. Here, we characterized the genetic diversity of Tilia  ×  europaea, one of the most widely planted urban tree species in Northwest Europe. We compared the genotypic diversity of historical plantings of Tilia spp. from the 17th century with the genotypic diversity of currently available planting stock in Belgium and the Netherlands. In total, 129 trees were sampled and genotyped with 14 microsatellite loci and 150 polymorphic Amplified Fragment Length Polymorphism markers. In Northwest Europe, homogenization of urban T.  ×  europaea plantings already started at the 17th century. Genetic diversity within contemporary commercial planting stocks was extremely narrow and consisted mainly of two clones, sold under the name ‘Pallida’ and ‘Zwarte linde’. The genetic diversity found within the historical plantings was about four times higher than in the current commercial planting stocks. We recommend that tree nurseries should enlarge the genetic diversity of T.  ×  europaea commercial planting stocks. The old clones have shown long-term disease resistance and could provide tree breeders with the valuable new genetic material. The range of available Tilia species and genotypes needs to be explored in future urban tree planning to optimize desired ecosystem services.

Urban trees form a vital component of sustainable cities but the use of a restricted range of species and genotypes may pose a risk to global biodiversity. Despite several studies investigating tree species diversity, intraspecific genetic diversity of urban trees remains largely unexplored. Here, we characterized the genetic diversity of Tilia x europaea, one of the most widely planted urban tree species in Northwest Europe. We compared the genotypic diversity of historical plantings of Tilia spp. from the 17th century with the genotypic diversity of currently available planting stock in Belgium and the Netherlands. In total, 129 trees were sampled and genotyped with 14 microsatellite loci and 150 polymorphic Amplified Fragment Length Polymorphism markers. In Northwest Europe, homogenization of urban T. x europaea plantings already started at the 17th century. Genetic diversity within contemporary commercial planting stocks was extremely narrow and consisted mainly of two clones, sold under the name 'Pallida' and 'Zwarte linde'. The genetic diversity found within the historical plantings was about four times higher than in the current commercial planting stocks. We recommend that tree nurseries should enlarge the genetic diversity of T. x europaea commercial planting stocks. The old clones have shown long-term disease resistance and could provide tree breeders with the valuable new genetic material. The range of available Tilia species and genotypes needs to be explored in future urban tree planning to optimize desired ecosystem services.

Despite extensive forest destruction in the Middle Ages and later intensive commercial forest management, remnants of virgin forests remained spared in some Central, Eastern and South-Eastern European countries. These virgin forests are the last examples of original forests in this part of Europe. That is why their protection becomes an important issue of current European forestry and nature protection policy. But the knowledge about the location and the area of virgin forests in these countries is incomplete up till now. This article has the prime goal to present a conceptual framework what virgin forests might be (“A conceptual framework for defining of virgin forests” section). Based on this framework, a working methodology has been tested in Bulgaria and Romania (“Results of the two national projects in Romania and in Bulgaria” section and further). For this reason two projects have been carried out by the Royal Dutch Society of Nature Conservation (KNNV) in close co-operation with the Forestry Institutes in Romania and in Bulgaria. The results of these projects are described in general terms and further analysis in the future is necessary to describe specific features like forest structure and spatial heterogeneity of these forests. Based on the results of the inventory, principles of sustainable protection and management of the mapped virgin forests were defined and described in the research reports. The usefulness of the inventory became evident already during the EU pre-accession period of both countries while preparing the NATURA 2000 network. The remaining virgin forests of temperate Europe are an inexhaustible source of ecological information about biodiversity, structure, natural processes and overall functioning of undisturbed forest ecosystems. Their research will reveal information which can be used for ecological restoration of man-made forests which are degraded through intensive forestry practices over the last centuries. The last virgin forests of temperate Europe represent an irreplaceable part of the natural capital of Europe and are worth to be protected by law. Their last remnants in South-Eastern and Eastern Europe are endangered by commercial activities. A full inventory of remaining virgin forests in all countries of temperate Europe is a matter of highest urgency. A representative selection of virgin forest sites should be declared by UNESCO as World Heritage Sites.

The genus Rosa has a complex evolutionary history caused by several factors, often in conjunction: extensive hybridization, recent radiation, incomplete lineage sorting, and multiple events of polyploidy. We examined the applicability of AFLP markers for reconstructing (species) relationships in Rosa, using UPGMA clustering, Wagner parsimony, and Bayesian inference. All trees were well resolved, but many of the deeper branches were weakly supported. The cluster analysis showed that the rose cultivars can be separated into a European and an Oriental cluster, each being related to different wild species. The phylogenetic analyses showed that (1) two of the four subgenera (Hulthemia and Platyrhodon) do not deserve subgeneric status; (2) section Carolinae should be merged with sect. Cinnamomeae; (3) subsection Rubigineae is a monophyletic group within sect. Caninae, making sect. Caninae paraphyletic; and (4) there is little support for the distinction of the five other subsections within sect. Caninae. Comparison of the trees with morphological classifications and with previous molecular studies showed that all methods yielded reliable trees. Bayesian inference proved to be a useful alternative to parsimony analysis of AFLP data. Because of their genome-wide sampling, AFLPs are the markers of choice to reconstruct (species) relationships in evolutionary complex groups.