Nazarov reagents for convergent and expedient synthesis of new steroids

[reaction: see text] A new methodology for the convergent synthesis of tetracyclic compounds was developed. Two new bicyclic Nazarov reagents of type II were synthesized, and their cycloaddition with 2-carbomethoxy-2-cyclohexenone I was studied. This cycloaddition afforded new interesting steroidal backbones.     

聚硫堇/过氧化氢光致电化学敏感界面的构建及其对葡萄糖氧化酶催化活性的测定

将具有光电活性的硫堇电聚合在光透电极的表面,制备了聚硫堇膜光电极,利用该电极同时具有光敏和电子受体的性能,使其与葡萄糖氧化酶对葡萄糖催化反应产生的电子供体(过氧化氢)发生光致电化学反应,通过检测由此产生的光电流实现对蛋白质催化活性的检测.本文探讨了聚硫堇/过氧化氢光致电化学敏感界面的响应机理,讨论了偏压、电解质溶液pH和底物浓度对光致电化学反应和测定葡萄糖氧化酶催化活性的影响.通过测定商品葡萄糖氧化酶的催化活性,验证了方法的可行性.应用该敏感界面检测蛋白质的催化活性不需要过氧化物酶,比光度法经济、简便和快速.     

二氯菊酸2－甲基－3－（2－呋喃基）－2－丙烯酯的合成

报导了一种新拟除虫菊酯的设计和合成。标题化合物是由二氯菊酰氯与新自制的２－甲基－３－（２－呋喃基）－２－丙烯－１－醇酯化合成。     

Adsorption of bovine serum albumin on nanosized magnetic particles

A new model was proposed to predict the adsorption equilibrium of mixtures composed of supercritical gases. The adsorbed phase was visualized as a two-dimensional nonideal compressed gas. Pore size distribution was used to describe the energetic heterogeneity of the surface, and the two-dimensional virial equation was used as the local adsorption isotherm. The new model obtained is thermodynamically rigorous because it reduces to Henry's law as pressure approaches zero. The prediction performance of the new model was verified and compared with other models using the experimental data of a ternary mixture of CH4/N2/H2 and two binary mixtures of CH4/C2H4 and CH4/N2. Better performance was shown for all systems tested.     

PdCl2-catalyzed cross-coupling reaction of arylacetylene iodides with arylboronic acids to diarylacetylenes

A new Suzuki-type cross-coupling reaction between 1-iodo-2-arylalkynes and arylboronic acids to afford a wide variety of functionalized diarylacetylenes in a mild reaction condition was developed. The reaction was catalyzed by a small amount of a structurally simple, commercially available, and stable PdCl₂. This unique sp-sp² carbon-carbon bond formation provides a new protocol for the synthesis of diarylacetylenes, which is a new addition to the Suzuki cross-coupling reaction.     

A new chiral 2-sulfonylamino-2′-phosphino-1,1′-binaphthyl ligand for highly enantioselective copper-catalyzed conjugate addition of diethylzinc to benzylideneacetones

A new axially chiral phosphine-sulfonamide ligand was prepared via a chiral component (R)-2-amino-2′-diphenylphosphinyl-1,1′-binaphthyl, which was conveniently synthesized through a new route involving hydrolysis of (R)-2-cyano-2′-phosphinyl-1,1′-binaphthyl followed by Hofmann rearrangement of the amide group. The new ligand was found to be very efficient in copper-catalyzed enantioselective conjugate addition of diethylzinc to acyclic enones such as benzylideneacetones, providing very high enantioselectivity up to 99% ee.     

甲醛在光催化降解反应中自由基中间体的电子顺磁共振研究

以纳米二氧化钛(TiO2)光催化降解甲醛, 使用2-甲基-2-亚硝基丙烷(2-methyl-2-nitroso-propane, MNP)作为自旋捕截剂(spin trap, ST), 研究了反应过程中的自由基中间体, 得到了一种新的自旋加合物(spin adduct, ST-R). 电子顺磁共振(Electron Paramagnetic Resonance, EPR)的结果表明, 甲醛在水溶液中降解的反应中间体为•CH(OH)2, 并提出了一种新的降解机理.     

A New Taxoid from Leaves and Branches of Taxus chinensis

A new taxoid, 2-deacetyl-2α, 14β-dihydroxybaccatin Ⅳ (1), was isolated from the leaves and branches of Taxus chinensis together with the known compound baccatin Ⅳ (2). The structure of the new compound was elucidated by spectroscopic techniques. The detailed ^13C NMR assignments of baccatin Ⅳ are reported for the first time.     

新型层柱微孔材料-XW11Co柱撑Zn-Al型层柱化合物的合成、表征及催化活性研究

采用水热合成与离子交换方法, 将中心原子不同的过渡金属(Co^2^+)取代型Keggin结构杂多阴离子XW11O39Co(H2O)^n^-(X=Ge^4^+, B^3^+和Co^2^+)嵌入Zn-Al型阴离子粘土层间, 合成了底面间距(d001)为1.46±0.01nm的新型层柱化合物Zn2Al-GeW11Co, Zn2Al-BW11Co和Zn2Al-CoW11Co; 通过XRD, IR, XPS和DTA等手段, 研究了它们的结构与性质, 推测了这些杂多阴离子(XW11Co)在层间的空间取向; 考察了这些新型层柱化合物对乙酸与n-丁醇酯化反应的催化活性; 吡啶吸附IR光谱研究结果表明, 它们同时具有B酸与L酸两种酸中心。     

Layered single-metal hydroxide/ethylene glycol as a new class of hybrid material

Neutral ethylene glycol (EG) molecules have been intercalated into zinc hydroxide layers to produce a new hybrid material in which only one kind of metal ion is included. Initially, layered basic zinc acetate (LBZA, Zn(5)(OH)(8)(CH(3)COO)(2).2H(2)O) was prepared from a methanolic zinc acetate dihydrate solution. The immersion of LBZA in EG resulted in its intercalation, which was accompanied by an interlayer expansion of 7.12 A, as revealed by X-ray diffractometry. A Fourier transform infrared spectroscopic study indicated that the new compound contained both the acetate groups and the EG molecules. Together with thermogravimetry-differential thermal analysis, a composition of the new compound was estimated to be Zn(5)(OH)(8)(CH(3)COO)(2)(HOC(2)H(4)OH)(2).2H(2)O. The EG intercalation was found to increase the dehydration temperature of the zinc hydroxide layers from 130 to 180 degrees C. So the thermally stable material is then promising as a new class of precursors in creating organic-inorganic nanocomposites.     

A new flavonoid and sulphur-containing amides from Glycosmis chlorosperma

A new flavonoid, dihydroglychalcone-A, was isolated from the leaves extract of Glycosmis chlorosperma in addition to two known sulphur-containing amides, dambullin and gerambullin. The structure of the new compound was assigned as 2'-hydroxy-4,6'-dimethoxy-3',4'-(2",2"-dimethylpyrano)dihydrochalcone. The extract of the leaves was also found to exhibit antimicrobial and cytotoxic activities.     

A new griseofulvin derivative from the mangrove endophytic fungus <Emphasis Type="Italic">Sporothrix</Emphasis> SP.

A new griseofulvin derivative, 7-chloro-2',5,6-trimethoxy-6'-methylspiro(benzofuran-2(3H),1'-(2) cyclohexene)3,4'-dione (1), together with the known 2-acetyl-7-methoxybenzofuran (2), was isolated from the marine-derived mangrove endophytic fungus Sporothrix sp. (No. 4335). The structure of new compound 1 was elucidated by analysis of spectroscopic data.     

A highly selective fluorescent chemosensor for Pb2+

A new fluorescent sensor based on rhodamine B for Pb2+ was synthesized. The new fluorescent sensor showed an extreme selectivity for Pb2+ over other metal ions examined in acetonitrile. Upon the addition of Pb2+, an overall emission change of 100-fold was observed, and the selectivity was calculated to be 200 times that of Zn2+. The signal transduction occurs via of reversible CHEF (chelation-enhanced fluorescence) with this inherent quenching metal ion.     

基于CO2气体释放法的煤燃烧特性研究

国内火电厂目前对于煤质的检测主要是通过常规的工业分析检测燃煤挥发分、碳、灰分和发热量等指标信息,指导锅炉的运行。在这些常规分析指标中,反映煤的燃烧特性主要是挥发分的多少。但是,仅凭挥发分来衡量煤的燃烧特性是不完全的[1]。此外由于条件限制,目前火电厂对于着火、燃尽等燃烧特性,无法得到。此前,国内一些研究单位采用热重分析技术对我国动力煤燃烧特性进行系统研究,并得到相应的指标。但由于热分析仪大都是从国外进口,仪器成本过高而无法推广和普及。本研究采用基于ＣＯ2气体释放法的煤燃烧特性研究可以较快得出煤的着火点、…     

Adsorption of cations onto the surfaces of silver nanoparticles

The effects of cations on the absorption spectra of silver sols have been investigated by the UV-vis spectrometry and TEM. Experiments showed that injection of certain amounts of transition metal cations into silver sols resulted not only in the aggregation of silver nanoparticles but also in the appearance of a new band centered near 510 nm in the absorption spectra of silver sols. However, the new band was not observed in the presence of alkaline earth metal cations or the Mv2+ cations. The peak position of the new band depends on the nature as well as the concentration of metal cations used. Comparing the peak positions of the new bands, it was found that the new band induced by the injection of Cr3+ was red-shifted with respect to those induced by Cu2+, Zn2+, or the Cd2+ cations. It is reasonable that this band near 510 nm should be attributed to the coeffects of the adsorption of metal cations onto the surfaces of silver nanoparticles and the aggregation of silver nanoparticles.     

A new cerebroside and its anti-proliferation effect on VSMCs from the radix of Cyperus rotundus L.

<正>A new cerebroside,1-O-(β-D-glucopyranosyloxy)-(2S,3R,4E,8Z)-2-[(2′R)-2'-hydroxylignoceranoylamino]-4,8-tetradecene-3- diol was isolated from the 60%EtOH extract of traditional Chinese medical plant Cyperus rotundus L.Its structure was determined on the basis of spectroscopic data.This new compound showed anti-proliferation effect on vascular smooth muscle cells(VSMCs).     

脱色阴离子交换剂的再生研究

提出一种新的离子交换剂再生理论，即吸附物的脱附依靠离子交换和络合的协同效应完成．以二价钙离子为再生剂，对糖液脱色用的阴离子交换树脂和阴离子交换纤维进行再生，并与传统的碱性钠盐相比较，研究证明钙离子为再生剂的工艺，具有低成本、无污染的特点．     

一种新的双光系统透明电极电池

植物光合作用在其叶绿体的光合作用膜上进行。它有两个串联着的光系统(PSII和PSI)。PSII在膜的一侧,吸收波长相当于680nm的光子激发电子并产生空穴,空穴将水氧化得氧。电子经过一系列的下坡传送,暗反应合成ATP,到处于膜另一侧的PSI。PSI吸收波长相当于700nm的光子,再次将电子激发,经过第二个系列的下坡传送,暗反应将NADP还原为NADHP。NADHP和ATP最终将CO₂还原为碳水化合物。     

Iridoid glucosides from Wendlandia tinctoria roots

A new iridoid glucoside, 8-O-(E)-caffeoylmussaenosidic acid (1), together with ixoside (2), was isolated from the roots of Wendlandia tinctoria. The structure of the new compound was established on the basis of detailed spectroscopic (2D NMR) and chemical analysis.     

可见光响应光催化剂BiYWO6的制备、表征及其完全分解水的研究

制备了一种可见光响应的光催化剂BiYWO6, 该体系是Bi2WO6-Y2WO6的伪二元固溶体, 其禁带宽度为2.71 eV. 其负载了助催化剂后, 可在紫外光和可见光下完全分解水生成氢气和氧气, 其中负载RuO2助催化剂的BiYWO6具有最好的光催化活性. 通过对光催化反应前后的BiYWO6和助催化剂的表面各元素的化学状态的研究证实了RuO2/BiYWO6体系的稳定性. 比较分析了BiYWO6的能带结构, 认为可见光完全分解水的性能可归因于Y和Bi在固溶体BiYWO6中形成了合适的能带结构.