Tris-hydroxymethylaminomethane (THAM): An efficient organocatalyst in diversity-oriented and environmentally benign synthesis of spirochromenes
Publication date: Available online 10 June 2018 Source:Comptes Rendus Chimie Author(s): Supriya S. Khot, Prashant V. Anbhule, Uday V. Desai, Prakash P. Wadgaonkar Tris-hydroxymethylaminomethane has been demonstrated to be an efficient organocatalyst in diversity-oriented synthesis of medicinally prevalent spirochromenes by one-pot, three-component reactions between isatins, malononitrile, and enolizable CH acids like dimedone, 4-hydroxycoumarin, 4-hydroxy-N-methylquinolin-2-one, or in situ generated 2-methylpyrazolon-2-one. Biodegradability and extremely low cost of the catalyst are the noteworthy features of this ch...
Source: Comptes Rendus Chimie - June 10, 2018 Category: Chemistry Source Type: research
Zeolite nanoparticles (H-ZSM5) as a highly efficient, green, and reusable heterogeneous catalyst for selective oxidation of sulfides to sulfoxides under mild conditions
Publication date: Available online 9 June 2018 Source:Comptes Rendus Chimie Author(s): Amin Rostami, Noosheen Saedmocheshi, Zeinab Shirvandi H-ZSM5 is applied as an efficient, highly reusable, and heterogeneous catalyst for the oxidation of sulfides to sulfoxides using 30% H2O2 under solvent-free conditions at room temperature. A variety of aromatic and aliphatic sulfides with different functional groups were successfully oxidized with good to excellent yields in short reaction times. The catalyst can be easily recovered by simple filtration and recycled for several consecutive runs without any significant loss of its...
Source: Comptes Rendus Chimie - June 9, 2018 Category: Chemistry Source Type: research
Workshop on alternative solvents for synthesis, extraction, purification, and formulation (WAS 2017)
Publication date: Available online 31 May 2018 Source:Comptes Rendus Chimie Author(s): Bruno Andrioletti, Ludivine Jean-Gérard, Anne-Sylvie Fabiano-Tixier, Farid Chemat (Source: Comptes Rendus Chimie)
Source: Comptes Rendus Chimie - June 1, 2018 Category: Chemistry Source Type: research
Materials from binary tetrahedral main group element units
Publication date: Available online 23 May 2018 Source:Comptes Rendus Chimie Author(s): Stefanie Dehnen Synthetic approaches to new materials are as various as the nature of the materials themselves. Here, we report on one synthetic concept that was used during the recent past to address a variety of different families of compounds from superionic conductors and supersphere cages for molecular trapping to new white-light generators and reactive multimetallic clusters. The use of small binary molecules comprising atoms of two main group elements is the base of all of the presented methodologies, which lead to the named cl...
Source: Comptes Rendus Chimie - May 24, 2018 Category: Chemistry Source Type: research
Potentialities of using liquefied gases as alternative solvents to substitute hexane for the extraction of aromas from fresh and dry natural products
Publication date: Available online 24 May 2018 Source:Comptes Rendus Chimie Author(s): Vincent Rapinel, Cyrille Santerre, Farnaz Hanaei, Justine Belay, Nadine Vallet, Njara Rakotomanomana, Alain Vallageas, Farid Chemat The potential of liquefied gases, n-butane, dimethyl ether, and HFO-1234ze as effective and green alternative solvents to substitute hexane has been evaluated for the extraction of aromatic compounds from dry lavender flowers (Lavandula angustifolia Mill.) and fresh orange peels (Citrus sinensis (L.) Osbeck). The performance of these liquefied gases as solvents has been evaluated in terms of yield,...
Source: Comptes Rendus Chimie - May 24, 2018 Category: Chemistry Source Type: research
Parameter optimization in microwave-assisted distillation of frankincense essential oil
In conclusion, MAD is a promising technology for producing olibanum oil with new qualitative attributes. (Source: Comptes Rendus Chimie)
Source: Comptes Rendus Chimie - May 22, 2018 Category: Chemistry Source Type: research
Solvent effects in the aza-Michael addition of anilines
Publication date: Available online 19 April 2018 Source:Comptes Rendus Chimie Author(s): Alena Fedotova, Evgeniy Kondrashov, Julien Legros, Jacques Maddaluno, Alexander Yu. Rulev The aza-Michael addition of functionally substituted anilines to enoates is significantly affected by the hydrogen bond donor ability of the solvent. Very polar protic fluorinated alcohols (hexafluoroisopropanol and trifluoroethanol) favor the addition of weak nucleophiles, whereas these solvents are no longer required for anilines bearing additional OH or NH2 group. Graphical abstract (Source: Comptes Rendus Chimie)
Source: Comptes Rendus Chimie - May 22, 2018 Category: Chemistry Source Type: research
Synergies and competition between current approaches to materials discovery
Publication date: Available online 21 April 2018 Source:Comptes Rendus Chimie Author(s): Martin Jansen Discovery of novel materials is impaired by lack of predictability of solid-state synthesis. In addressing this impediment, an approach toward rational planning of syntheses of solid state and materials is presented. Within the underlying “chemical energy landscape” concept, the whole materials world is projected onto an energy landscape, associated with a respective configuration space. Evidently, all chemical compounds possible are present in virtuo in such a landscape. For the identification of targets for synth...
Source: Comptes Rendus Chimie - May 22, 2018 Category: Chemistry Source Type: research
Some aspects of green solvents
Publication date: Available online 23 April 2018 Source:Comptes Rendus Chimie Author(s): Katharina Häckl, Werner Kunz Chemical solvents constitute around 80% of the total volume of chemicals used in many important chemical processes, especially fine chemical manufacturing. Unfortunately, these solvents are often volatile organic compounds from petroleum resource bearing several health and environmental risks. Numerous researchers take these two aspects as a reason to search for novel green solvents to replace the conventional ones. As a consequence, there are an increasing number of publications dealing with green sol...
Source: Comptes Rendus Chimie - May 22, 2018 Category: Chemistry Source Type: research
From hydrophilic to hydrophobic wood using direct fluorination: A localized treatment
Publication date: Available online 24 April 2018 Source:Comptes Rendus Chimie Author(s): Martial Pouzet, Marc Dubois, Karine Charlet, Alexis Béakou When controlled by the treatment duration or the quantity of reactive molecules, direct fluorination using F2 gas is efficient to decrease the hydrophilicity of wood both in the form of massive piece and powder. To prove that silver fir pieces and wood flour (mix of spruce and silver fir species) were investigated as representative examples. In both the cases, hydroxyl groups are converted into CF bonds resulting in the decrease in affinity for water. Fluorination is mai...
Source: Comptes Rendus Chimie - May 22, 2018 Category: Chemistry Source Type: research
Magnetic recyclable eggshell-based mesoporous catalyst for biodiesel production from crude neem oil: Process optimization by central composite design and artificial neural network
Publication date: Available online 25 April 2018 Source:Comptes Rendus Chimie Author(s): Adewale S. Oladipo, Olusegun A. Ajayi, Akeem A. Oladipo, Solmaz L. Azarmi, Yusuf Nurudeen, Abdulazeez Y. Atta, Shola S. Ogunyemi A magnetically recyclable eggshell-based catalyst (MKEC) was synthesized to circumvent saponification during the conversion of neem, Jatropha, and waste cooking oils (free fatty acid, 2.3–6.6%) to biodiesel. The characterization results indicated that MKEC had a mesoporous structure with the pore width of 3.24 nm, a specific surface area of 128 m2/g, and a pore volume of 0.045 cm3/g. The results...
Source: Comptes Rendus Chimie - May 22, 2018 Category: Chemistry Source Type: research
Controlled pinewood fractionation with supercritical ethanol: A prerequisite toward pinewood conversion into chemicals and biofuels
In this study, the conversion of each pinewood component was determined by the analysis of solid residues to quantify cellulose, hemicellulose, lignin, and char contents. It is shown that, by tuning the temperature, hemicellulose and lignin are already transformed in subcritical ethanol conditions, lignin being more reactive than hemicellulose. In contrast, native wood cellulose is recalcitrant to liquefaction in SC ethanol near the critical point (T c = 241 °C and P c = 61 bar), but 20% of native wood cellulose is converted in SC ethanol at 280 °C. Besides, the severity of the conditions, in terms of temperature ...
Source: Comptes Rendus Chimie - May 22, 2018 Category: Chemistry Source Type: research
Reprogramming the chemical reactivity of iron in cancer stem cells
Publication date: Available online 4 May 2018 Source:Comptes Rendus Chimie Author(s): Tatiana Cañeque, Sebastian Müller, Anne Lafon, Fabien Sindikubwabo, Antoine Versini, Lou Saier, Manon Barutaut, Christine Gaillet, Raphaël Rodriguez Cancer stem cells (CSCs) have been shown to be refractory to conventional therapeutic agents, can promote metastasis, and have been linked to cancer relapse. Salinomycin can selectively kill CSCs. We have shown that salinomycin derivatives accumulate in lysosomes and sequester iron in this organelle. As a result, accumulation of iron leads to the production of reactive oxygen sp...
Source: Comptes Rendus Chimie - May 22, 2018 Category: Chemistry Source Type: research
Helically chiral functionalized [6]helicene: Synthesis, optical resolution, and photophysical properties
Publication date: Available online 7 May 2018 Source:Comptes Rendus Chimie Author(s): Nesrine Hafedh, Faouzi Aloui, Vincent Dorcet, Houcine Barhoumi A short and efficient synthetic pathway leading to a new chiral π-conjugated system is reported. The X-ray structure of the target compound was determined and showed a helical conformation. Its resolution was successfully accomplished, leading to two enantiomers in high optical purity, and their chiroptical properties were examined experimentally. The photophysical properties of the organic material were also evaluated, showing an emission in the visible region, and HOM...
Source: Comptes Rendus Chimie - May 22, 2018 Category: Chemistry Source Type: research
Photocatalytic and photosensitized water splitting: A plea for well-defined and commonly accepted protocol
Publication date: Available online 8 May 2018 Source:Comptes Rendus Chimie Author(s): Arindam Indra, Prashanth W. Menezes, Matthias Driess The amount of “free” energy provided by the sun in 1 h is more than what currently mankind uses from fossil fuels and other renewable energy sources. Water covers 71% of the earth surface, making it easily available and one of the cheapest natural resources. Therefore, the concept of sunlight-driven water splitting (oxygen and hydrogen evolution) by converting the solar energy into chemical energy could be a cheap substitute for fuels and thus is of paramount interest. Moreove...
Source: Comptes Rendus Chimie - May 22, 2018 Category: Chemistry Source Type: research
