Simple preparation of enantiomeric Michael adducts of thiophenol to chalcones: easily available new chiral building blocks

A facile and enantioselective method for the multigram preparation of the title compounds is described. The Michael addition of thiophenols to chalcones catalyzed by (+)-cinchonine, followed by crystallization, led to the corresponding adducts 2 in up to >95% e.e. The stereoselective Beckmann rearrangement of the oxime of (+)-1,3-diphenyl-3-phenylsulfanylpropan-1-one 2a gives the anilide of (R)-(+)-3-phenyl-3-phenylsulfanylpropanoic acid (as determined by X-ray analysis) and alcoholysis leads to the corresponding enantiomerically pure ethyl ester.     

Determination of processed animal proteins, including meat and bone meal, in animal feed

An intercomparison study was conducted to determine the presence of processed animal proteins (PAPs), including meat and bone meal (MBM) from various species, in animal feed. The performances of different methods, such as microscopy, polymerase chain reaction (PCR), immunoassays, and a protocol based on iquid chromatography (LC), were compared. Laboratories were asked to analyze for PAPs from all terrestrial animals and fish (total PAPs); mammalian PAPs; ruminant PAPs; and porcine PAPs. They were free to use their method of choice. In addition, laboratories using microscopy were asked to determine the presence of PAPs from terrestrial animals, which is applicable only to microscopy. For total PAPs microscopy, LC and some immunoassays showed sufficient results at a concentration as low as 0.1% MBM in the feed. In contrast, PCR was not fit for purpose. In differentiating between MBM from terrestrial animals and fishmeal, microscopy detected 0.5% of terrestrial MBM in feed in the presence of 5% fishmeal, but was less successful when the concentration of MBM from terrestrial animals was 0.1%. The animal-specific determination of MBM from mammals or, more specifically from either ruminants or pigs, by PCR showed poor results, as indicated by a high number of false-positive and false-negative results. The only PCR method that scored quite well was applied by a member of the organizer team of the study. Immunoassays scored much better than PCR, showing sufficient sensitivity but some deficiency in terms of specificity. The results also demonstrated that the reliable determination of MBM from ruminants has not been resolved, especially for low concentrations of MBM (0.1%) in feed. Comparison of the results for mammalian MBM from all methods indicated that, for control purposes, the immunoassay method, especially when applied as dipsticks, could be used as a rapid screening method combined with microscopy to confirm the positive samples. However, implementation of such a system would require that the immunoassays were previously validated to demonstrate that this approach is fit for purpose. The determination of ruminant or porcine PAPs by immunoassays was more difficult, partly because the MBM in this study contained about 50% bovine and porcine material, thereby reducing the target concentration level to 0.05%.     

Efficient and eco-friendly preparation of 4-methyl-5-formyl-thiazole

4-Methyl-5-formylthiazole, an intermediate for synthesizing cefditoren pivoxil,was prepared in good yield by Pd/BaSO(4) catalyzed hydrogenation of 4-methylthiazole-5-carboxylic acid chloride. Detailed reaction conditions have been studied.     

Pyrrolidine-pyridine base catalysts for the enantioselective Michael addition of ketones to chalcones

A series of pyrrolidine-pyridine base organocatalysts have been developed and 3a found to be a highly effective catalyst for the asymmetric Michael addition reactions of ketones to chalcones. The reaction generated the corresponding products 1, 5-diketones in excellent diastereoselectivities (up to >99:1 dr) and enantioselectivities (up to 100% ee).     

New eco-friendly low-cost binders for Li-ion anodes

In the production of commercial Li-ion batteries, the active materials slurries are generally prepared using polyvinylidene fluoride (PVdF) as binder because of its good adhesion properties and electrochemical stability. Unfortunately, there are some disadvantages related to the use of PVdF: the most important is the use of toxic and environmentally unfriendly solvents, such as N-methyl-pyrrolidone (NMP), and the second is the high costs. In the light of these considerations, it seemed straightforward to investigate the suitability of some water-soluble, inexpensive, and eco-friendly materials to test as alternative binders (sodium alginate, chitosan tragacanth gum, gelatin). The rheological properties of these materials have been investigated in addition to the electrochemical characterization. Furthermore, graphite electrodes with PVdF, carboxymethyl cellulose (CMC), and styrene-butadiene rubber (SBR) binders have been considered for sake of comparison. We found that some of these water-soluble binders, besides good electrochemical performances, showed a high adhesion to the current collector and a good electrochemical stability under the experimental conditions employed, which makes them interesting for the next generation of Li-ion batteries.     

New scalable and eco-friendly synthesis of gingerols

Synthesis of 6-gingerol and its congeners 7- and 9-gingerols has been achieved from eugenol by a new scalable and eco-friendly protocol. The key steps are functionalization of eugenol to the nitro compound and its reaction under optimized condition with terminal alkenes to afford intermediate isoxazolines. The latter on catalytic hydrogenation in presence of Raney nickel afford corresponding gingerols in good yields.     

New approach to the preparation of catalysts for the oxidative coupling of methane

A new approach to the preparation of systems that exhibit catalytic activity in the oxidative coupling of methane (OCM) is considered. With the use of ferrospheres separated from power-generation ashes from different sources as an example, it was demonstrated that OCM catalysts can be prepared by the crystallization/solidification of oxide melts with the formation of microspherical particles. The dependence of activity and selectivity for the oxidative reforming of methane on the ferrospheres containing from 36.2 to 92.5 wt % Fe₂O₃ into the products of deep oxidation and OCM was studied. It was found that deep oxidation reactions on ferrospheres with Fe₂O₃ contents higher than 85% were suppressed, and the main reaction path of CH₄ conversion was its oxidative coupling with the formation of C₂ products (with selectivity to 60% at 750°C); moreover, the selectivity for C₂ formation in this region was proportional to the concentration of Fe₂O₃. Phases responsible for the catalytic conversion of methane into CO _x and OCM products were considered, and it was shown that the catalytic activity and selectivity of the oxidative transformation of CH₄ on ferrospheres is determined by the position of the point that corresponds to their composition on a phase diagram of CaO-Fe₂O₃-SiO₂.     

Synthetic studies towards the mulberry Diels-Alder adducts: H-bond accelerated cycloadditions of chalcones

The methyl ether derivatives 2, 4 and 6 of the mulberry Diels-Alder adducts chalcomoracin (1) and mulberrofuran C (3) and kuwanon J (5) respectively have been synthesized by a thermal [4 + 2]-cycloaddition reaction between a chalcone and dehydroprenyl diene. A H-bonded ortho OH substituent on the chalcone was found to be essential for Diels-Alder reactivity. Density functional theory calculations show that the OH group lowers the barrier for the Diels-Alder reaction by 2-3 kcal mol(-1) compared with OMe. The acceleration by the OH group is traced to two transition-state effects: a stronger diene-chalcone interaction and better planarity of the aryl-diene unit.     

Detection of bovine meat and bone meal in animal feed at a level of 0.1%

For the control of the transmission of bovine spongiform encephalopathy in cattle via feedstuff, a real-time polymerase chain reaction assay was developed with ruminant-specific Bov-B SINE primers, SYBR Green fluorescence detection, and melting curve analysis. In formulated cattle and chicken feed samples spiked with pure bovine and sheep meat and bone meal heated at 133 degrees C for 20 min, a contamination level of 0.1% was detected.     

Synthesis and application of chalcones to the preparation of heterocyclic structures

Condensation of methyl N-(4-acetylphenyl)carbamate with aromatic aldehydes in basic and acid environment, and also with hetarylaldehydes in the presence of bases afforded chalcones with the carbamate function. Under the conditions of basic catalysis a nucleophilic substitution was observed of a methoxy group in the carbamate moiety of the chalcone for an ethoxy group. The reactions of the obtained chalcones with hydrazine hydrate, isonicotinic acid hydrazide, guanidine and hydroxylamine hydrochlorides, thiourea, and selenium dioxide furnished the corresponding derivatives of pyrazole, oxazole, pyrimidine, and selenadiazole.     

离子液体催化甘油和尿素合成甘油碳酸酯

将一系列酸性、碱性和中性的功能化离子液体用于催化甘油和尿素合成甘油碳酸酯。结果表明,中性离子液体表现出更高的催化活性。离子液体阳离子和阴离子的协同效应促进了反应的进行,离子液体阳离子的正电性活化尿素,阴离子的负电性活化甘油,并且催化剂酸碱位点的平衡对催化反应过程也有一定的影响。此外,离子液体可以实现回收利用至少五次,且催化活性基本不变。采用功能化离子液体替代传统金属催化剂,减少了不可再生资源的利用,且所用原料为廉价易得的生物基原料,过程中也不使用有机溶剂,环境友好。     

Exploitation the unique acidity of novel cerium-tungstate catalysts in the preparation of indole derivatives under eco-friendly acid catalyzed Fischer indole reaction protocol

Solid acidic cerium tungstate catalysts containing different molar ratios of cerium and tungstate were prepared by direct solvothermal methodology. The structure of the prepared catalysts was deeply studied and confirmed based on different characterization techniques such as DTA-TGA, FTIR, Raman spectra, XRD and N₂ adsorption measurements. Moreover, FTIR and TPD of chemically adsorbed pyridine techniques were conducted to fully address the nature and the strength of the acidic sites of the prepared catalysts. The study showed that at a lower molar ratio of tungstate, the catalyst contains cerium oxide phase and slight participation of cerium tungstate phase, which gradually increases with further increase of tungstate molar ratio. This phase change was also accompanied by a noticeable change in the thermal stability, surface area and acidic properties of the prepared catalysts. Additionally, the techniques used to study the acidic properties showed an excellent enhancement in the acidic centers. It was also noted that the strength of these acidic centers reached the maximum in the case of using tungstate: cerium molar ratio 2:1 (CeW2.0) catalyst, and slightly decreased thereafter. By exploiting the acidic properties of the prepared catalysts, a series of indole derivatives were synthesized via the Fischer indole synthesis strategy. The results also showed that ～100% of indole derivatives were obtained using 0.02 g catalyst at 80 °C after 2 h only. Moreover, the Reuse experiment demonstrated the possibility of recycling and reusing the catalyst through many cycles with high efficiency, indicating its wonderful constancy and reusability.     

New chalcones containing carbazole and 3,4-ethylenedioxythiophene fragments

Russian Journal of Organic Chemistry - Acylation of 9-(2-ethylhexyl)carbazole with acetyl bromide in the presence of tin(IV) chloride gave 3-acetyl- and 3,6-diacetyl-9-(2-ethylhexyl)carbazoles...     

A convenient synthesis of 1,2,4-trisubstituted azetidines by reductive cyclization of aza-Michael adducts of chalcones

Aza-Michael adducts of chalcones and diethyl N-arylphosphoramidates undergo reductive cyclization with sodium borohydride followed by sodium hydride to afford 1,2,4-trisubstituted azetidines diastereoselectively in a one-pot procedure and excellent yields.     

New possibilities for preparation of highly dispersed PtFe/SiO2 catalysts

Pt(CH₃)₃Cl complex has been applied for preparation of highly dispersed Pt/SiO₂ catalyst. Iron in different forms was used as second component for PtFe/SiO₂ catalyst. Dispersity of Pt is comparable to that obtained via Pt(NH₃) ₄ ²⁺ exchange. Catalytic activity and isomerization are explained in terms of Fe blocking of the surface.

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Pt(CH₃)₃Cl Pt/SiO₂. PtFe/SiO₂. Pt(NH₃) ₄ ⁺² . .

     

Correction to: New eco-friendly low-cost binders for Li-ion anodes

Journal of Solid State Electrochemistry - The article New eco-friendly low-cost binders for Li-ion anodes, written by D. Versaci, R. Nasi, U. Zubair, J. Amici, M. Sgroi, M. A. Dumitrescu, C....     

Heterogeneous dehydrocoupling of amine-borane adducts by skeletal nickel catalysts

Skeletal Ni, produced by the selective leaching of Al from a Ni/Al alloy, has been successfully employed in the catalytic dehydrogenation of various amine-borane adducts. The combination of low cost and facile single-step synthesis make this system a potentially attractive alternative to the previously described precious metal and other first-row metal catalysts. The heterogeneous nature of the catalyst facilitates convenient product purification, and this is the first such system to be based on a first-row transition metal. Catalytic dehydrocoupling of Me(2)NH·BH(3) (1) and Et(2)NH·BH(3) (5) was demonstrated using 5 mol % skeletal Ni catalyst at 20 °C and produced [Me(2)N-BH(2)](2) (2) and [Et(2)N-BH(2)](2)/Et(2)N═BH(2) (6), respectively. The related adduct iPr(2)NH·BH(3) (7) was also dehydrogenated to afford iPr(2)N═BH(2) (8) but with significant catalyst deactivation. Catalytic dehydrocoupling of MeNH(2)·BH(3) (9) was found to yield the cyclic triborazane [MeNH-BH(2)](3) (10) as the major product, whereas high molecular weight poly(methylaminoborane) [MeNH-BH(2)](n) (11) (M(w) = 78?000 Da, PDI = 1.52) was formed when stoichiometric quantities of Ni were used. Similar reactivity was also observed with NH(3)·BH(3) (12), which produced cyclic oligomers and insoluble polymers, [NH(2)-BH(2)](x) (14), under catalytic and stoichiometric Ni loadings, respectively. Catalyst recycling was hindered by gradual poisoning. A study of possible catalyst poisons suggested that BH(3) was the most likely surface poison, in line with previous work on colloidal Rh catalysts. Catalytic dehydrogenation of amine-borane adducts using skeletal Cu and Fe was also explored. Skeletal Cu was found to be a less active dehydrogenation catalyst for amine-borane adducts but also yielded poly(methylaminoborane) under stoichiometric conditions on reaction with MeNH(2)·BH(3) (9). Skeletal Fe was found to be completely inactive toward amine-borane dehydrogenation.     

Thermal decomposition of meat and bone meal

A series of runs has been performed to study the thermal behavior of meat and bone meal (MBM) both in inert and reactive atmosphere. Although they are actually burned, the thermal decomposition of such MBM wastes has not been studied from a scientific point of view until now. The aim of this work is to present and discuss the thermogravimetric behavior of MBM both in nitrogen and air atmospheres. A thermobalance has been used to carry out the study at three different heating rates. A kinetic scheme able to correlate simultaneously (with no variation of the kinetic constants) the runs performed at different heating rates and different atmospheres of reaction is presented.     

Proline adducts of metallo-organic,sextuply-stranded lanterns as homogeneous catalysts for asymmetric catalysis

Two homochiral metal–organic, sextuply-stranded, lantern-like complexes, Ce-L-Pro1 and Ce-D-Pro1, were synthesized via self-assembly by incorporating a L or D-pyrrolidine moiety within the respective ligands. The Ce-Pro1 complexes are comprised of chiral pyrrolidine-containing ligands and have lantern-like cavities. They function as asymmetric catalysts that promote cyanosilylation reactions with good conversions and enantioselectivity.