Rapid,sensitive separation of the three main isoflavones in soybean using immunoaffinity chromatography

Daidzin, genistin, and glycitein are major isoflavone compounds in soybean that are indispensable nutrients in traditional Chinese foods. Generally, strategies for detecting and separating soy isoflavones have been based on HPLC and chromatographic techniques, which are tedious and time‐consuming procedures. In the present study, we developed an ELISA‐based approach for daidzin detection using a broad‐specificity monoclonal antibody (clone number: AA9) with an effective detection range of 10–10 000 ng/mL. Subsequently, we prepared an immunoaffinity column by coupling the monoclonal antibody AA9 to CNBr‐activated Sepharose 4B. Our results demonstrate that the immunoaffinity column can efficiently and specifically extract daidzin, glycitein, and genistin from numerous structurally similar soy isoflavones in leguminous plants, thereby providing a new method for the extraction of target components from similar compounds in natural products.     

CO<Subscript>2</Subscript> Biofixation of <Emphasis Type="Italic">Actinobacillus succinogenes</Emphasis> Through Novel Amine-Functionalized Polystyrene Microsphere Materials

CO₂-derived succinate production was enhanced by Actinobacillus succinogenes through polystyrene (PSt) microsphere materials for CO₂ adsorption in bioreactor, and the adhesion forces between A. succinogenes bacteria and PSt materials were characterized. Synthesized uniformly sized and highly cross-linked PSt microspheres had high specific surface areas. After modification with amine functional groups, the novel amine-functionalized PSt microspheres exhibited a high adsorption capacity of 25.3 mg CO₂/g materials. After addition with the functionalized microspheres into the culture broth, CO₂ supply to the cells increased. Succinate production by A. succinogenes can be enhanced from 29.6 to 48.1 g L^?1. Moreover, the characterization of interaction forces between A. succinogenes cells and the microspheres indicated that the maximal adhesive force was about 250 pN. The amine-functionalized PSt microspheres can adsorb a large amount of CO₂ and be employed for A. succinogenes anaerobic cultivation in bioreactor for high-efficiency production of CO₂-derived succinate.     

Asymmetric Multicomponent Reactions Based on Trapping of Active Intermediates

Metal carbenes derived from transition metal‐catalyzed decomposition of diazo compounds react with nucleophiles with heteroatoms, such as alcohols and amines, to generate highly active oxonium/ammonium ylides intermediates. These intermediates can be trapped by appropriate electrophiles to provide three‐component products. Based on this novel trapping process, we have developed novel multicomponent reactions (MCRs) of diazo compounds, alcohols/anilines, and electrophiles. The nucleophiles were also extended to electron‐rich heterocycles (indoles and pyrroles)/arenes, in which the resulting zwitterionic intermediates were also trapped by electrophiles. By employing efficient catalysis strategy, the reactions were realized with excellent stereocontrol and wide substrate scope. In this personal account, we introduce our breakthroughs in the development of novel asymmetric MCRs via trapping of the active ylides and zwitterionic intermediates with a number of electrophiles, such as imines, aldehyde, and Michael acceptors, under asymmetric catalysis. Transition metal/chiral Lewis acid catalysis, transition metal/Brønsted acid catalysis, and chiral transition‐metal catalysis, enable excellent stereocontrolled outcomes. The methodologies not only provide experimental evidence to support the existence of protic onium ylides intermediates/zwitterionic intermediates and the stepwise pathways of carbene‐induced O?H, N?H and C?H insertions, but also offer a novel approach for the efficient construction of chiral polyfunctional molecules.     

Trapping of oxonium ylide with isatins: efficient and stereoselective construction of adjacent quaternary carbon centers

The 3-substituted 3-hydroxyindolin-2-ones with adjacent quaternary stereocenters were constructed in a single step via an efficient and stereoselective trapping of oxonium ylide with isatins. This reaction proceeds well in supercritical CO2 and is an example of the ability to use green approaches to efficiently construct polyfunctional molecules.     

碱性介质中制备纳米四氧化三锰及其超级电容特性

比较了不同碱溶液中纳米Mn₃O₄的制备及其超级电容性能。用X射线粉末衍射仪、扫描电子显微镜和原子力显微镜等技术手段分别测试了晶体结构和表面形貌。用循环伏安、恒流充放电和交流阻抗测试了材料的电化学性能。结果表明,在氢氧化钠、氨水中Mn²⁺沉淀氧化可以直接制备纳米Mn₃O₄;碳酸钠中先生成MnCO₃,加氢氧化钠可转化为纳米Mn₃O₄。NaOH、NH₃和Na₂CO₃ 3种介质中制备的Mn₃O₄晶粒尺寸分别为29.5、20.2和36.3 nm。纳米Mn₃O₄经连续充放电循环后可活化为Birnessite-type MnO₂。氨水中制备的Mn₃O₄活化后比容量最大,达到239 F/g,是一种具有应用前景的超级电容器材料。     

Divergent Synthesis of Multisubstituted Tetrahydrofurans and Pyrrolidines via Intramolecular Aldol‐type Trapping of Onium Ylide Intermediates

This paper reports a divergent strategy for the synthesis of multisubstituted tetrahydrofurans and pyrrolidines, starting from easily accessible β‐hydroxyketones or β‐aminoketones to react with diazo compounds. Under Rh^II catalysis, this transformation is proposed to proceed through a metal–carbene‐induced oxonium ylide or ammonium ylide formation followed by an intramolecular aldol‐type trapping of these active intermediates. A series of highly substituted tetrahydrofurans and pyrrolidines are synthesized in high yields with good to excellent diastereoselectivities. Preliminary biological evaluations revealed that both types of heterocycles show good PTP1B inhibitory activities.     

手性螺环配体及催化剂在不对称催化反应中的应用研究进展

金属参与的不对称催化反应是制备光学活性化合物的重要途径之一, 其中新型手性配体的设计合成一直是不对称催化领域中十分关键且富有挑战性的课题. 从20世纪90年代末开始, 化学家们尝试在手性配体中引入螺环结构, 创造性地发展了螺[4.4]壬烷骨架、 螺双二氢茚骨架、 螺[4.4]壬二烯骨架和螺二色满骨架等手性螺环单齿配体, 多齿配体及其催化剂, 并成功应用于不对称催化氢化、 不对称碳碳键形成或碳杂键形成等不对称转化反应中, 合成了众多富有价值的手性产品, 有力地推动了不对称催化反应的工业应用化进程. 本文综合评述了手性螺环配体的早期发现、 发展历程以及近期的研究成果, 介绍了螺环配体在药物及天然产物中的应用研究进展, 并对手性螺环结构的小分子催化剂的研究进展进行叙述和说明.     

Diastereoselectivity switch in cooperatively catalyzed three-component reactions of an aryldiazoacetate, an alcohol, and a β,γ-unsaturated α-keto ester

A highly switchable,diastereoselectivity-controlled, three-component reaction of aryldiazoacetate, alcohol,and β,γ-unsaturated α-keto esters has been achieved through a dual-metal cooperative catalysis strategy.     

Diastereoselective three-component reactions of aryldiazoacetates with alcohols/water and alkynals: application to substituted enelactones

Dirhodium acetate catalyzed three-component reactions of aryl diazoacetates, alcohols or water, and 2-alkynals are reported to afford β-alkynyl α,β-dihydroxyl acid esters in good yield with high diastereoselectivity. Synthetic utility of the reaction was demonstrated in the conversion of the versatile alkynyl functionality to other synthetically useful compounds, including efficient synthesis of 2-aryl-2,3-dihydroxyl enelactones.