Search results for " Cat"
showing 10 items of 7219 documents
Synthesis of 1,3-bis(trimethylcyclam) and 1,3-bis(trimethylcyclen) substituted benzenes
2009
Pd-catalyzed amination of 1,3-dibromobenzene with N,N',N''-trimethylcyclam and N,N',N''-trimethylcyclen provided corresponding 1,3-bis(tetraazamacrocyclic) derivatives of benzene in 25-32% yields. The dependence of the products yields on the phosphine ligand applied (BINAP, DavePHOS) as well as on the stoichiometry of starting compounds was established. Scope and limitations for the synthesis of N-phenyl and N-(3-bromophenyl) derivatives of trimethylcyclam and trimethylcyclen were demonstrated.
Supported Polyhedral Oligomeric Silsesquioxane-Based (POSS) Materials as Highly Active Organocatalysts for the Conversion of CO2
2018
Very high turnover numbers (TON) and productivity values up to 7875 and 740 respectively have been obtained for the conversion of CO2 into cyclic carbonates by using hybrid materials based on imidazolium modified polyhedral oligomeric silsesquioxanes (POSS-Imi) grafted on amorphous silica (SiO2) and mesostructured SBA-15. The heterogeneous organocatalysts were easily prepared via a straightforward synthetic procedure allowing to generate high local concentration spots of imidazolium active sites surrounding the POSS core. This synthetic procedure is also a promising approach for the design of a wide library of hybrid functional materials. The materials do not possess other co-catalytic spec…
Ionic Liquid Gels: Supramolecular Reaction Media for the Alcoholysis of Anhydrides.
2019
The search of new enantioselective catalysts, able to promote synthetically useful organic reactions with high levels of asymmetric induction, should be associated with the attention to the suitable reaction medium able to achieve the best efficiency in chemical processes. We have investigated the enantioselective desymmetrization of cyclic meso-anhydrides in nonconventional reaction media such as ionic liquids and supramolecular gels. With this aim, we examined several variables in the reacting system: the nature of ionic liquid used as the reaction medium, the gelation solvent, the structure of the anhydrides, the structure of alcohols, the chiral catalysts, and the reaction conditions, i…
First titanium-catalyzed 1,4-hydrophosphination of 1,3-dienes
2010
International audience
Catalytic Carbonylative Double Cyclization of 2-(3-Hydroxy-1-yn-1-yl)phenols in Ionic Liquids Leading to Furobenzofuranone Derivatives
2019
A catalytic carbonylative double cyclization method for the synthesis of furo[3,4-b]benzofuran-1(3H)-ones is reported. It is based on the reaction between readily available 2-(3-hydroxy-1-yn-1-yl)phenols, CO, and oxygen carried out in the presence of catalytic amounts of PdI2 (1 mol %) in conjunction with KI (20 mol %) and 2 equiv of diisopropylethylamine at 80 degrees C for 24 h under 30 atm of a 1:4 mixture of CO-air. Interestingly, the process was not selective when carried out in classical organic non-nucleophilic solvents (such as MeCN or DME), leading to a mixture of the benzofurofuranone derivative and the benzofuran ensuing from simple cycloisomerization, whereas it turned out chemo…
Copper-Catalyzed Aerobic Oxidative Alkynylation of 3,4-Dihydroquinoxalin-2-ones
2019
Herein, we described a ligand-free copper-catalyzed aerobic oxidative functionalization of 3,4-dihydroquinoxalin-2(1H)-ones with terminal alkynes using visible-light and oxygen as terminal oxidant to give 3-ethynyl-3,4-dihydroquinoxalin-2(1H)-one, cyclic propargylic amines, in moderate to good yields. Moreover, we demonstrate the versatility of the 3-ethynyl-3,4-dihydroquinoxalin-2(1H)-ones obtained by preparing several 3,4-dihydroquinoxalin-2-one derivatives.
Electrochemical Arylation Reaction
2018
Arylated products are found in various fields of chemistry and represent essential entities for many applications. Therefore, the formation of this structural feature represents a central issue of contemporary organic synthesis. By the action of electricity the necessity of leaving groups, metal catalysts, stoichiometric oxidizers, or reducing agents can be omitted in part or even completely. The replacement of conventional reagents by sustainable electricity not only will be environmentally benign but also allows significant short cuts in electrochemical synthesis. In addition, this methodology can be considered as inherently safe. The current survey is organized in cathodic and anodic con…
Toxicity and Binding Studies of Bacillus thuringiensis Cry1Ac, Cry1F, Cry1C, and Cry2A Proteins in the Soybean Pests Anticarsia gemmatalis and Chryso…
2017
ABSTRACT Anticarsia gemmatalis (velvetbean caterpillar) and Chrysodeixis includens (soybean looper, formerly named Pseudoplusia includens ) are two important defoliating insects of soybeans. Both lepidopteran pests are controlled mainly with synthetic insecticides. Alternative control strategies, such as biopesticides based on the Bacillus thuringiensis (Bt) toxins or transgenic plants expressing Bt toxins, can be used and are increasingly being adopted. Studies on the insect susceptibilities and modes of action of the different Bt toxins are crucial to determine management strategies to control the pests and to delay outbreaks of insect resistance. In the present study, the susceptibilitie…
Climate Change Genomics Calls for Standardized Data Reporting
2020
The advent of new and affordable high-throughput sequencing techniques allows for the investigation of the genetic basis of environmental adaptation throughout the plant and animal kingdom. The framework of genotype-environment associations (GEA) provides a powerful link by correlating the geographic distribution of genotype patterns of individuals or populations with environmental factors on a spatial scale. We coarsely review the short history of GEA studies, summarizing available studies, organisms, data type, and data availability for these studies. GEA is a powerful tool in climate change research and we therefore focus on climate variables as environmental factors. While our initial a…
Changes in freshwater sediment microbial populations during fermentation of crude glycerol
2020
This work was supported by the Latvian Council of Science , project NN-CARMA, project No. lzp-2018/1-0194.