Synthesis of 4H-cyclopenta[c]furans via cooperative PdCl2-FeCl2 catalyzed cascade cyclization reaction involving a novel acyl rearrangement process

We have discovered a novel PdCl(2)-FeCl(2) catalyzed cascade cyclization reaction, which involves a novel acyl rearrangement process. This reaction affords a diverse set of poly-substituted 4H-cyclopenta[c]furan products. The reaction scope of this cascade process is quite broad and various internal acetylenes can be employed.     

Synthesis,structure, and host-guest properties of an anthracene-based macrocyclic arene

A new anthracene-based macrocyclic host (H) was designed and synthesized. H has a molecular box-type structure with a flexible cavity. It exhibits highly strong binding affinities towards selected cationic model guests, butyl viologen (BV), dibutylammonium (DBA), and octyltrimethylammonium (OTMA). For example, the association constant of H and BV is up to (2.2?±?0.3)?×?10⁷?M^?1; it is interesting to observe host-guest charge-transfer band (and color change) and fluorescence quenching of H’s anthracene unit due to the formation of inclusion complex.     

N-取代-5-磺酰基吡唑肟醚衍生物的合成及生物活性研究

以吡唑酮、盐酸羟胺、硫酚、2-氯-5-氯甲基吡啶等化合物为原料,设计合成了5个未见文献报道的磺酰基吡唑肟醚新化合物,其结构经元素分析、1HNMR、IR和MS验证。初步生物活性测试表明,部分化合物具有一定的杀菌活性。     

Can Polyethylene be a Photo(bio)Degradable Synthetic Polymer?

Abstract

A polymeric system based on LDPE would be qualified as a “photo(bio)degradable synthetic polymer” for use as films or thin systems in plasticulture and later in packaging where severe specific criteria should be respected. The evolution of such a system in environmental conditions should present three phases. In Phase I, corresponding to storage and use, in the presence of physicochemical and biological aggression, chemical evolution should be very limited and resistance to any microorganism should be observed. In Phase II a rapid abiotic degradation should occur until the complete destruction of physical (mechanical) properties and spontaneous fragmentation of the thin systems into more and more divided parts. Phase III corresponds to bioassimilation of heavily transformed (oxidized) solid particles. Phase I should be predicted and controlled on the basis of artificial photoaging or thermoaging experiments. Depending on the desired lifetime of the system, nonaccelerated, accelerated, or ultra-accelerated photoaging techniques could be used. The earliest fragmentation, which should be observed in Phase II, should be predicted within the same experiment. The prediction of the long-term fate of the polymeric materials should be based not only on the variations of physical properties but on a full analysis of the chemical evolution, i.e., determination of the major final transformed groups of the macromolecular chains (and especially the acidic end groups) and the molar mass distribution. In a recent BRITE-EURAM European contract, we developed an experimental protocol for the control of Phase III based on the use of pure cultures of strains from collections or selected adapted wild strains (from industrial polyethylene site dumpings) which had been examined. Abiotically oxidized LDPE was the only carbon source in a starving mineral medium. Bioerodibility caused by the carboxylic acid formed throughout abiotic degradation has been observed.     

Carbon dioxide-mediated synthesis of 3(2H)-furanones from diyne alcohols

A novel type of carbon dioxide-mediated reaction of diyne alcohols without any metal catalysts was reported. Carbon dioxide held the key to the success of this reaction, in which 3(2H)-furanones were selectively obtained in moderate to high yields.     

The effects of sodium chloride on the explosive performance of ammonium nitrate

Sodium chloride (NaCl) was added to the ammonium nitrate (AN) by different mixing methods. The heat sensitivity performance and the explosive performance of AN and ammonium nitrate fuel oil (ANFO) were studied by using differential scanning calorimeter (DSC), the UN gap test and Koenen test. The results show that: When AN contained 15 % (solution mixing) and 35 % (mechanical mixing) additive, AN maximum exothermic peak increased from 286.75 to 300.63 and 307.83 °C, respectively. For the mechanical mixing, the critical values of the UN gap test and Koenen test AN were 35 and 40 %. The ANFO both were 50 %; for the solution mixing, AN were 15 and 40 %, the critical value of the UN gap test, ANFO was 25 %. AN and ANFO contain more than the critical value of additive, the AN and ANFO would not be detonated.     

基于VMD-ELM的农产品期货价格分解集成预测模型

为了捕捉农产品市场期货价格波动的复杂特征,进一步提高其预测精度,基于分解集成的思想,构建包含变分模态分解(VMD)和极限学习机(ELM)的分解集成预测模型。首先,利用VMD分解的自适应性和非递归性,选择VMD将复杂时间序列分解成多个模态分量(IMF)。其次,针对VMD分解关键参数模态数K的选取难题,提出基于最小模糊熵准则寻找最优K值的方法,有效避免模态混淆和端点效应问题,从而提升VMD的分解能力。最后,利用ELM强大的学习能力和泛化能力,对VMD分解得到的不同尺度子序列进行预测,集成得到最终预测结果。以CBOT交易所稻谷、小麦、豆粕期货价格作为研究对象,实证结果表明,该分解集成预测模型在预测精度和方向性指标上,显著优于单预测模型和其它分解集成预测模型,为农产品期货价格预测提供了一种新途径。     

Towers of derivation for Lie rings and some results on complete Lie rings

The well-known tower theorem of groups (resp. Lie algebras) shows that the tower of automorphism groups (resp. derivation algebras) of a finite group (resp. a finite dimensional Lie algebra) with trivial center terminates after finitely many steps. We generalize these results for Lie rings, and present some necessary and sufficient conditions for Lie rings to be complete.     

TOWERS OF DERIVATION FOR LIE RINGS AND SOME RESULTS ON COMPLETE LIE RINGS

The well-known tower theorem of groups （resp. Lie algebras） shows that the tower of automorphism groups （resp. derivation algebras） of a finite group （resp. a finite dimensional Lie algebra） with trivial center terminates after finitely many steps. We generalize these results for Lie rings, and present some necessary and sufficient conditions for Lie rings to be complete.