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用硅烷化双聚体结构分析胶凝物质的聚合趋向 被引量:6
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作者 王晓钧 霍明江 +1 位作者 闫继娜 杨南如 《硅酸盐学报》 EI CAS CSCD 北大核心 2000年第6期575-577,共3页
对G级油井水泥、矿渣、赤泥、压蒸粉煤灰和有机硅水解物等含有硅氧四面体结构的物质进行三甲基硅烷化 (TMS)处理 ,用气相色谱分析上述物质TMS产物中双聚体结构的特征 ,提出可以根据TMS产物双聚体的不同结构来判定胶凝物质今后的聚合趋... 对G级油井水泥、矿渣、赤泥、压蒸粉煤灰和有机硅水解物等含有硅氧四面体结构的物质进行三甲基硅烷化 (TMS)处理 ,用气相色谱分析上述物质TMS产物中双聚体结构的特征 ,提出可以根据TMS产物双聚体的不同结构来判定胶凝物质今后的聚合趋向 .在胶凝物质硅烷化双聚体衍生物的 4种结构中 ,不对称的结构为主时 ,该胶凝物质今后有不对称的聚合趋向 ,表现出具有速凝性 ;而在胶凝物质双聚体的 4种结构中 ,线形对称结构为主时 ,线形对称聚合是它的趋向之一 ,该胶凝物胶凝相对缓慢 . 展开更多
关键词 甲硅烷化 双聚体 凝胶物质 气相色谱 聚合
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硅橡胶用胶体白炭黑的补强作用 被引量:1
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作者 朱永康 《世界橡胶工业》 2005年第8期32-39,共8页
在有酸和异丙醇参与的情况下,胶体白炭黑的水悬浮液与氯硅烷或二硅氧烷易发生甲硅烷化,而白炭黑粒子却不会产生聚集现象。利用氯硅烷或二硅氧烷的混合物,可制得官能度可控的球形白炭黑纳米粒子,并转化为有机相,形成稳定的无水悬浮体。... 在有酸和异丙醇参与的情况下,胶体白炭黑的水悬浮液与氯硅烷或二硅氧烷易发生甲硅烷化,而白炭黑粒子却不会产生聚集现象。利用氯硅烷或二硅氧烷的混合物,可制得官能度可控的球形白炭黑纳米粒子,并转化为有机相,形成稳定的无水悬浮体。憎水性的白炭黑粒子容易分散进入硅橡胶中。在充足的填充量下,它们的补强性能与传统填料不相上下,且能提高胶料透明度,降低粘度。通过改变填料粒子中的乙烯基浓度和聚合物相中的乙烯基浓度之比,能够控制硫化物的模量及硬度。 展开更多
关键词 胶体白炭黑 补强 橡胶 纳米粒子 甲硅烷化
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GC-MS同时测定番石榴叶中的齐墩果酸和熊果酸 被引量:14
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作者 黄建林 张展霞 《分析测试技术与仪器》 CAS 2005年第3期178-181,共4页
建立了测定番石榴叶中齐墩果酸和熊果酸的气相色谱-质谱(GC-MS)方法.以双(三甲硅烷)三氟乙酰胺(BSTFA)为衍生化试剂,将齐墩果酸和熊果酸制成三甲基硅烷衍生物后,在DB-5 MS毛细管柱上进行分离.柱升温程序为:柱初温100 ℃,恒温保持2 min, ... 建立了测定番石榴叶中齐墩果酸和熊果酸的气相色谱-质谱(GC-MS)方法.以双(三甲硅烷)三氟乙酰胺(BSTFA)为衍生化试剂,将齐墩果酸和熊果酸制成三甲基硅烷衍生物后,在DB-5 MS毛细管柱上进行分离.柱升温程序为:柱初温100 ℃,恒温保持2 min, 以10 ℃/min的速度升温至300 ℃,保持14 min.通过与标准样品对照比较保留时间和质谱确认样品中齐墩果酸和熊果酸的色谱峰.以峰面积进行定量测定,齐墩果酸和熊果酸的线性范围分别为4.1~102 μg/mL和4.7~114 μg/mL,回收率分别为77.1%和89.4%,6次平行测定的相对标准偏差分别为3.7%和3.5%. 展开更多
关键词 番石榴叶 齐墩果酸 熊果酸 双(三)三氟乙酰胺衍生
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Cationic Ring Opening Polymerization of Octamethylcyclotetrasiloxane Initiated by Acid Treated Bentonite 被引量:5
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作者 陈碧 詹晓力 +1 位作者 易玲敏 陈丰秋 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2007年第5期661-665,共5页
Cationic ring opening polymerization of octamethylcyclotetrasiloxane (Da) initiated by acid treated bentonite was investigated. The experimental conditions were chosen on the basis of preliminary experiments.Higher ... Cationic ring opening polymerization of octamethylcyclotetrasiloxane (Da) initiated by acid treated bentonite was investigated. The experimental conditions were chosen on the basis of preliminary experiments.Higher temperature was found beneficial for the reaction process while stirring intensity beyond a certain level showed no obvious effect on the reaction rate. Polymers were characterized by Fourier transform infrared, proton nuclear magnetic resonance (IH-NMR) and gel perneation chromotography. The width of molecular mass distribution was found ranging between 1.2 and 1.4, which is extraordinarlly narrow compared with that of cationic polymerizations reported elsewhere (〉 1.9). The results were believed due to the absence of free proton and counter ion which simplifies the polymerization process and the huge steric hindrance provided by bentonite particles which keeps the propagation of polysiloxane onto the surface of bentonite particles in a much more regular way. A feasible mechanism is proposed and seems to be supported well by experiments. Additionally, from the results of α, ω-dihydrogen terminated polysiloxanes prepared, the possibility of applying this potential environmentally friendly heterogeneous catalyst in industrial polymerization of cyclosiloxanes is anticipated. 展开更多
关键词 OCTAMETHYLCYCLOTETRASILOXANE cationic polymerization POLYSILOXANE
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Zinc phthalocyanine as an efficient catalyst for halogen-free synthesis of formamides from amines via carbon dioxide hydrosilylation under mild conditions 被引量:3
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作者 Rongchang Luo Xiaowei Lin +2 位作者 Jing Lu Xiantai Zhou Hongbing Ji 《Chinese Journal of Catalysis》 CSCD 北大核心 2017年第8期1382-1389,共8页
The combination of a zinc phthalocyanine(ZnPc)catalyst and a stoichiometric amount of dimethyl formamide(DMF)provided a simple route to formamide derivatives from amines,CO2,and hydrosilanes under mild conditions.We d... The combination of a zinc phthalocyanine(ZnPc)catalyst and a stoichiometric amount of dimethyl formamide(DMF)provided a simple route to formamide derivatives from amines,CO2,and hydrosilanes under mild conditions.We deduced that formation of an active zinc‐hydrogen(Zn‐H)species promoted hydride transfer from the hydrosilane to CO2.The cooperative activation of the Lewis acidic ZnPc by strongly polar DMF,led to formation of activated amines and hydrosilanes,which promoted the chemical reduction of CO2.Consequently,the binary ZnPc/DMF catalytic system showed excellent yields and superior chemoselectivity,representing a simple and sustainable pathway for the reductive transformation of CO2into valuable chemicals as an alternative to conventional halogen‐containing process. 展开更多
关键词 Carbon dioxide Zinc phthalocyanine Cooperative effect N‐formylation HYDROSILANES
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Modification of methyl oleate for silicon-based biological lubricating base oil 被引量:1
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作者 Shixing Cui Zhi Yun Xia Gui 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第1期130-136,共7页
A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative ... A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative of methyl oleate.Trimethylsilylation reaction was introduced to further improve methyl oleate oxidation stability and lubricity after epoxidation and open-ring reactions.The order of effectiveness of acid binding agent was N,N-diisopropylethylamine(DIEA) > pyridine > diethylamine > triethylamine,and the effects of various parameters on the trimethylsilylation reaction as well as on the silicon-oxygen bond stability and reaction yield were studied.A maximum yield of 34.54%was achieved at hydroxyl/trimethyl chlorosilane/DIEA molar ratio of1:1.25:1,reaction temperature 40℃,reaction time 1.5 h. 展开更多
关键词 Methyl oleate Trimethyl chlorosilane Acid binding agent N N-diisopropylethylamine Lubricity Silicon-based biological lubricating base oil
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Chemical vapor deposition of SiC at different molar ratios of hydrogen to methyltrichlorosilane 被引量:1
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作者 杨艳 张伟刚 《Journal of Central South University》 SCIE EI CAS 2009年第5期730-737,共8页
Chemical vapor deposition(CVD) of SiC from methyltrichlorosilane(MTS) was studied at two different molar ratios of H2 to MTS(n(H2) /n(MTS) ) . The total pressure was kept as 100 kPa and the temperature was varied from... Chemical vapor deposition(CVD) of SiC from methyltrichlorosilane(MTS) was studied at two different molar ratios of H2 to MTS(n(H2) /n(MTS) ) . The total pressure was kept as 100 kPa and the temperature was varied from 850 to 1 100 ℃ at a total residence time of 1 s. Steady-state deposition rates as functions of reactor length and of temperature,investigated at different n(H2) /n(MTS) values,show that hydrogen exhibits strongly influences on the deposition rate. Especially,the deposition of Si co-deposit can be obtained in broader substrate length and at higher temperatures with increasing hydrogen partial pressure. Influence of hydrogen on the deposition process was also studied using gas phase composition and deposit composition analysis at various n(H2) /n(MTS) . SEM micrographs directly show the variation of surface morphologies at various n(H2) /n(MTS) . It can be found that the crystal grain of the deposit at 1 100 ℃ is better developed and the crystallization is also improved with increasing n(H2) /n(MTS) . 展开更多
关键词 METHYLTRICHLOROSILANE silicon carbide H2 MTS
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Modeling of Pervaporation Separation Benzene from Dilute Aqueous Solutions Through Polydimethylsiloxane Membranes 被引量:1
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作者 彭福兵 姜忠义 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2005年第3期343-349,共7页
A modified solution-diffusion model was established based on Flory-Huggins thermodynamic theory and Fujita's free volume theory. This model was used for description of the mass transfer of removal benzene from dil... A modified solution-diffusion model was established based on Flory-Huggins thermodynamic theory and Fujita's free volume theory. This model was used for description of the mass transfer of removal benzene from dilute aqueous solutions through polydimethylsiloxane (PDMS) membranes. The effect of component concentration on the interaction parameter between components, that of the polymer membrane on the selectivity to benzene, and that of feed concentration and temperature on the permeation flux and separation factor of benzene/water through PDMS membranes were investigated. Calculated pervaporation fluxes of benzene and water were compared with the experimental results and were in good agreement with the experimental data. 展开更多
关键词 PERVAPORATION separation model BENZENE water polydimethylsiloxane membrane
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Kinetic and Microstructure of SiC Deposited from SiCl_4-CH_4-H_2 被引量:1
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作者 杨艳 张伟刚 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2009年第3期419-426,共8页
Silicon carbide was prepared from SiCl4-CH4-H2 gaseous precursors by isothermal, isobaric chemical vapor deposition (CVD) at atmospheric pressure and temperatures ranging from 900°C to 1100°C. Kinetic studie... Silicon carbide was prepared from SiCl4-CH4-H2 gaseous precursors by isothermal, isobaric chemical vapor deposition (CVD) at atmospheric pressure and temperatures ranging from 900°C to 1100°C. Kinetic studies showed that carbosilane of SiH2Cl2, SiHCl3 and SiCl2 formed from decomposition of SiCl4 and CH4 contributed to the deposition of hexangular facet and granular pebble structured SiC. An average apparent activation energy of 152 kJ·mol-1 was determined. The overall CVD process was controlled not only by the surface reactions but also by complex gas phase reactions. The as-deposited thin film was characterized using scanning electron microscopy, X-ray diffraction and transmission electron microscopy, these analysis showed that the deposited thin film consisted of pure phase of the β-SiC, the growth morphology of β-SiC differs from hexangular facet to granular pebble struc-tures, which varied with substrate length and CVD temperature. 展开更多
关键词 chemical vapor deposition SIC KINETICS MICROSTRUCTURE
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Ethanol Recovery from Fermentation Broth by Pervaporation Using a Composite polydimethylsiloxane Membrane 被引量:2
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作者 伍勇 黄卫星 +1 位作者 肖泽仪 钟月华 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2004年第4期586-589,共4页
The pervaporation behavior of fermentation broth was investigated experimentally and compared with those started with ethanol mixtures. Ethanol was produced by Saccharomyces cerevisiae utilizing technical grade glucos... The pervaporation behavior of fermentation broth was investigated experimentally and compared with those started with ethanol mixtures. Ethanol was produced by Saccharomyces cerevisiae utilizing technical grade glucose and recovered by pervaporation using a composite polydimethylsiloxane (PDMS) membrane prepared in our laboratory. Ethanol concentration in fermentation broth decreased to a relatively low level when pervaporation was coupled with fermentation. The more active cells appeared in the fermentation broth, the better the membrane performance was. 展开更多
关键词 ETHANOL FERMENTATION PERVAPORATION composite polydimethylsiloxane membrane
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Lipase-catalyzed Kinetic Resolution of Racemic 1-Trimethylsilylethanol in Organic Solvent 被引量:2
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作者 吴虹 宗敏华 +2 位作者 王菊芳 罗涤衡 娄文勇 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2004年第3期421-424,共4页
The enantioselective esterification of racemic 1-trimethylsilylethanol with acids catalyzed by lipase in organic solvent was successfully performed. The influence of some factors on the reaction was investigated. Amon... The enantioselective esterification of racemic 1-trimethylsilylethanol with acids catalyzed by lipase in organic solvent was successfully performed. The influence of some factors on the reaction was investigated. Among the four lipases explored, Candida rugosa lipase (CRL) showed the highest activity and enantioselectivity. Octanoic acid was the best acyl donor among the eleven acids studied and n-hexane was the most suitable medium for the reaction. The optimum shaking rate and temperature were found to be 150r·min-1 and 20℃ to 30℃, respectively. The enantiomeric excess of the remaining (5)-(-)-1-trimethylsilylethanol was 93% when substrate conversion was 53% upon incubation of the reaction mixture at 30℃, 150r·min-1 for 12 h. 展开更多
关键词 Candida rugosa lipase enantioselective esterification kinetic resolution racemic 1-trimethylsilylethanol
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Reductive transformation of CO_2:Fluoride-catalyzed reactions with waste silicon-based reducing agents
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作者 Ken Motokura Masaki Naijo +2 位作者 Sho Yamaguchi Akimitsu Miyaji Toshihide Baba 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2017年第3期434-439,共6页
CO_2 is one of the most important "renewable" carbon sources.To transform CO_2 to useful organic compounds,we examined the reactivity of two model silicon-based "waste" materials,disilanes and metallic Si powder,a... CO_2 is one of the most important "renewable" carbon sources.To transform CO_2 to useful organic compounds,we examined the reactivity of two model silicon-based "waste" materials,disilanes and metallic Si powder,as reducing agents.In these reactions,fluoride salts were found to be active catalysts:CO_2 was converted to formic acid at atmospheric pressure in the presence of H_2O as a proton source and the silicon-based reducing reagents.Based on in-situ NMR and kinetics analyses,a hydrosilane and penta-coordinate Si species are proposed as the reaction intermediate and active species,respectively. 展开更多
关键词 Carbon dioxide FLUORIDE Homogeneous catalysis Formic acid DISILANE
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Pervaporation Separation of Butanol-Water Mixtures Using Polydimethylsiloxane/Ceramic Composite Membrane 被引量:18
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作者 刘公平 侯丹 +2 位作者 卫旺 相里粉娟 金万勤 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2011年第1期40-44,共5页
Pervaporation has attracted considerable interest owing to its potential application in recovering biobutanol from biomass acetone-butanol-ethanol (ABE) fermentation broth. In this study, butanol was recovered from it... Pervaporation has attracted considerable interest owing to its potential application in recovering biobutanol from biomass acetone-butanol-ethanol (ABE) fermentation broth. In this study, butanol was recovered from its aqueous solution using a polydimethylsiloxane (PDMS)/ceramic composite pervaporation membrane. The effects of operating temperature, feed concentration, feed flow rate and operating time on the membrane pervaporation performance were investigated. It was found that with the increase of temperature or butanol concentration in the feed, the total flux through the membrane increased while the separation factor decreased slightly. As the feed flow rate increased, the total flux increased gradually while the separation factor changed little. At 40°C and 1% (by mass) butanol in the feed, the total flux and separation factor of the membrane reached 457.4 g·m?2·h?1 and 26.1, respectively. The membrane with high flux is suitable for recovering butanol from ABE fermentation broth. 展开更多
关键词 PERVAPORATION BUTANOL PDMS CERAMIC composite membrane
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Rational design and precise manipulation of nano‐catalysts 被引量:1
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作者 Qinggang Liu Junguo Ma Chen Chen 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第4期898-912,共15页
Nano‐catalysis plays a vital role in the chemical transformations and significantly impacts the booming modern chemical industry.The rapid technological enhancements have resulted in serious energy and environmental ... Nano‐catalysis plays a vital role in the chemical transformations and significantly impacts the booming modern chemical industry.The rapid technological enhancements have resulted in serious energy and environmental issues,which are currently spurring the exploration of the novel nano‐catalysts in diverse fields.In order to develop the efficient nano‐catalysts,it is essential to understand their fundamental physicochemical properties,including the coordination structures of the active centers and substrate‐adsorbate interactions.Subsequently,the nano‐catalyst design with precise manipulation at the atomic level can be attained.In this account,we have summarized our extensive investigation of the factors impacting nano‐catalysis,along with the synthetic strategies developed to prepare the nano‐catalysts for applications in electrocatalysis,photocatalysis and thermocatalysis.Finally,a brief conclusion and future research directions on nano‐catalysis have also been presented. 展开更多
关键词 Nano‐catalysis Single‐atom catalysts Water splitting Oxygen reduction reaction CO_(2)reduction reaction Silane oxidation Benzene oxidation N‐formylation
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Highly Efficient Asymmetric Transcyanation of Acetyltrimethylsilane with Acetone Cyanohydrin Catalyzed by (R)-Oxynitrilase from Prunus Japonica Seed Meal
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作者 黄舜荣 吴虹 宗敏华 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2005年第5期663-668,共6页
Highly efficient asymmetric transcyanation of acetyltrimethylsilane with acetone cyanohydrin in an aqueous/organic biphasic system catalyzed with (R)-oxynitrilase from defatted Prunus Japonica seed meal for the prep... Highly efficient asymmetric transcyanation of acetyltrimethylsilane with acetone cyanohydrin in an aqueous/organic biphasic system catalyzed with (R)-oxynitrilase from defatted Prunus Japonica seed meal for the preparation of optically active (R)-2-trimethylsilyl-2-hydroxyl-propionitrile was successfully carried out for the first time. For better understanding of the reaction, various influential variables were examined with respect to the initial reaction rate, the substrate conversion and the product enantiomeric excess (e.e.). Diisopropyl ether was found to be the best organic phase for this reaction among all the organic solvents tested. The optimal concentrations of Prunus Japonica seed meal powder, acetyltrimethylsilane and acetone cyanohydrin, volume ratio of aqueous phase to organic phase, buffer pH value and the reaction temperature were 34.5g·L^-1 and 14mmol· L^-1, 28mmol· L^-1, 13% (by volume), 5.0 and 30℃, respectively, while the initial reaction rate, the substrate conversion and the product enantiomeric excess were 1.34 mmol·L^-1·h^-1, 99.0% and 99.0%, respectively. The comparative study demonstrated that silicon atom in substrate showed great effect on the reaction and acetyltrimethylsilane was a much better substrate for (R)-hydroxynitrile lyase from Prunus Japonica seed than its carbon analogue 3,3-dimethyl-2-butanone. 展开更多
关键词 asymmetric transcyanation acetyltrimethylsilane (R)-oxynitrilase (R)-2-trimethylsilyl-2-hydroxylpropionitrile
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Synthesis of Thiol-functionalized Mesoporous Materials for Hg2. Trapping
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作者 Zeid A. Alothman Allen W. Apblett 《Journal of Environmental Science and Engineering》 2010年第1期1-8,共8页
Mesoporous silica materials with uniform channels containing functionalized organic monolayers have been synthesized by grafting a thiol functional group, (3-Mercaptopropyl) trimethoxysilane (MPTMS). A new approac... Mesoporous silica materials with uniform channels containing functionalized organic monolayers have been synthesized by grafting a thiol functional group, (3-Mercaptopropyl) trimethoxysilane (MPTMS). A new approach to heavy metal ion adsorbents based on the covalent grafting of MPTMS groups to the framework pore walls of mesoporous silica molecular sieves has been developed and investigated with regard to hydroxyl group densities, channel dimensions, morphologies and reaction conditions. Results show that the ordered mesostructures of functionalized samples were retained after modification and the thiol functional group was immobilized mainly inside the mesopore channel. The relative surface coverage of the monolayer can be systematically varied up to 95%. The functionalized hybrid materials show exceptional selectivity and capacity for removing mercury from aqueous waste stream with distribution coefficients up to 435,000. The regenerated material show high mercury ion uptake capacity of 2.87 mmol/g (86.5%). 展开更多
关键词 MESOPOROUS thiol-functional groups ADSORPTION Hg2+
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Determination of free fatty acids in rabbit plasma by GC-MS after trimethylsilylation derivatization 被引量:2
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作者 Jialin Du Liangjiu Yang +3 位作者 Kezhao Wei Can Gong Jianping Gao Xu Xu 《Journal of Chinese Pharmaceutical Sciences》 CAS CSCD 2020年第6期411-421,共11页
In the present study, free fatty acids(FFAs, including palmitic acid, stearic acid, oleic acid, linoleic acid and arachidonic acid) in rabbit plasma were determined by gas chromatography-mass spectrometry(GC-MS) after... In the present study, free fatty acids(FFAs, including palmitic acid, stearic acid, oleic acid, linoleic acid and arachidonic acid) in rabbit plasma were determined by gas chromatography-mass spectrometry(GC-MS) after trimethylsilylation derivatization using N,O-bis(trimethylsilyl)trifluoroacetamide(BSTFA) – trimethylchlorosilane(TMCS) as derivatization reagent. The experimental conditions, including extraction and silylation reaction, were investigated. The method was experimentally validated. The linearity between fatty acids’ peak areas and their concentrations was obtained with the corelative coefficient(r2) all more than 0.999, and the recoveries were between 82% and 111%. The intra-day variations of FFAs’ in plasma samples at different concentrations were all less than 6%. FFA analysis results of 16 rabbit plasma samples showed that the method could be well applied in the determination of plasma samples in vivo. In contrast to the traditional method of FFA derivatization, the established trimethylsilylation method presented simplicity, high specificity, and completely free from the interference of the esterified fatty acid, such as triacylglyceride. The method could be applied for analyzing FFA profiles in the clinical laboratory or pharmacological research. 展开更多
关键词 Free fatty acid TRIMETHYLSILYLATION DERIVATIZATION Gas chromatography-mass spectrometry Rabbit plasma
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A novel and versatile method for the enantioselective syntheses of tropane alkaloids 被引量:3
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作者 MAO ZhongYi HUANG SuYu +2 位作者 GAO LongHui WANG AiE HUANG PeiQiang 《Science China Chemistry》 SCIE EI CAS 2014年第2期252-264,共13页
A full account of the novel and flexible approach to hydroxylated 8-azabicyclo[3,2,1]octan-3-ones and 9-azabicyclo[3,3,1] nonan-3-ones is presented. Using keto-lactams as the starting materials, this two-step method c... A full account of the novel and flexible approach to hydroxylated 8-azabicyclo[3,2,1]octan-3-ones and 9-azabicyclo[3,3,1] nonan-3-ones is presented. Using keto-lactams as the starting materials, this two-step method consists of silyl enol ether for mation with TBDMSOTf, lactam activation with Tf20/DTBMP, and halide-promoted cyclization. Radical dechlorination of the resulting 1-halotropan-3-ones led to the corresponding hydroxylated tropan-3-ones, which can be hydrogenated to yield 3ct,613-dihydroxytropanes. Starting from optically active keto-lactams, the method has been applied to the enantioselective syntheses of (+)-(1S,3S,5R,6S)-pervilleine C (6), (+)-(1S,3R,5S,6R)-valeroidine (3), (+)-(1S,3S,5R,6S)-dibenzoyloxytropane (8) and (+)-(1S,3S,5R,6S)-merredissine (9). 展开更多
关键词 synthetic methods tropane alkaloids CYCLIZATION ACTIVATION AMIDES
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Post-functionalization of disubstituted polyacetylenes via click chemistry
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作者 TONG Li QIN AnJun +3 位作者 ZHANG XiaoA MAO Yu SUN JingZhi TANG Ben Zhong 《Science China Chemistry》 SCIE EI CAS 2011年第12期1948-1954,共7页
We report a synthetic design and the experimental exploration of preparation of disubstituted polyacetylenes (PAs, P3) through 1,3-dipolar cycloaddition of azides with precursor PA bearing alkyne pendants. The precu... We report a synthetic design and the experimental exploration of preparation of disubstituted polyacetylenes (PAs, P3) through 1,3-dipolar cycloaddition of azides with precursor PA bearing alkyne pendants. The precursor PA (P2) was derived by desilylation of the pristine PA with trimethylethynylsilane side chains (P1). P1 was obtained by polymerization of a dual-alkyne containing monomer with one of the alkynes end-capping by trimethylsilane (M) under the promotion of WC16-Ph4Sn catalyst. Two synthetic routes, i.e. two-steps (from P1 to P3 via precursor P2) and one-pot (from P1 to P3 without separation and purification of P2) were tried and the results indicated that one-pot strategy is more facile and resultant P3-1 showed higher purity and higher molecular weight than the resultant of P3-2. By using the techniques such as GPC, FTIR and 1H NMR spectroscopy the polymerization behavior and the structures of the polymers were well characterized. 展开更多
关键词 disubstituted polyacetylene click chemistry one-pot method selective polymerization
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