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141.
Back Cover: Silver‐Catalyzed Cross‐Coupling of Propargylic Alcohols with Isocyanides: An Atom‐Economical Synthesis of 2,3‐Allenamides (Chem. Eur. J. 8/2014) 下载免费PDF全文
142.
Jian Wen Li‐Li Zhu Qing‐Wei Bi Zhu‐Qing Shen Xiao‐Xiao Li Xin Li Zhen Wang Prof. Zili Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(4):974-978
Hydrogen‐bond mediated coupling of 1,2,3‐triazoles to indoles and pyrroles results in N2 selective functionalization of the triazole moiety in moderate to excellent yields. The reaction was tolerant of un‐, mono‐ and disubstituted triazoles and was applied to synthesize tryptophan derived fluorescent amino acids. 相似文献
143.
Silver‐Catalyzed Cross‐Coupling of Propargylic Alcohols with Isocyanides: An Atom‐Economical Synthesis of 2,3‐Allenamides 下载免费PDF全文
Jianquan Liu Zhenhua Liu Nannan Wu Dr. Peiqiu Liao Prof. Xihe Bi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(8):2154-2158
Cross‐coupling reactions between propargylic alcohols and isocyanides, by means of silver catalysis, have been described. This new reaction is both atom and step efficient and is applicable to a broad scope of substrates, allowing the synthesis of a range of synthetically valuable 2,3‐allenamides in moderate to excellent yields. 相似文献
144.
Bi Xiong Pingping Zhao Kai Hu Lina Zhang Gongzhen Cheng 《Cellulose (London, England)》2014,21(3):1183-1192
Urea can improve the solubility and stability of cellulose in aqueous alkali solution, while its role has not come to a conclusion. To reveal the role of urea in solution, NMR was introduced to investigate the interaction between urea and the other components in solution. Results from chemical shifts and longitudinal relaxation times show that: (1) urea has no strong direct interaction with cellulose as well as NaOH; (2) urea does not have much influence on the structural dynamics of water. Urea may play its role through van der Waals force. It may accumulate on the cellulose hydrophobic region to prevent dissolved cellulose molecules from re-gathering. The driving force for the self-assembly of cellulose and urea molecules might be hydrophobic interaction. In the process of cellulose dissolution, OH? breaks the hydrogen bonds, Na+ hydrations stabilize the hydrophilic hydroxyl groups and urea stabilizes the hydrophobic part of cellulose. 相似文献
145.
采用光-流变学方法研究了丙烯酸酯/液晶复合体系的光聚合凝胶时间及体积收缩率,并与密度法测量的体积收缩率进行了对比.结果表明,该复合体系的凝胶时间小于10 s,光-流变学方法可以在线测量丙烯酸酯单体/液晶复合体系的光聚合体积收缩.以2种不同结构的多面体齐聚倍半硅氧烷(POSS)掺杂丙烯酸酯/液晶复合体系,八甲基丙烯酰氧基倍半硅氧烷(MA-POSS)使丙烯酸酯/液晶复合体系的双键转化率略有降低,掺杂10 wt%MA-POSS使体系的光聚合体积收缩率仅降低了12%;而甲基丙烯酰氧基七异丁基倍半硅氧烷(MI-POSS)对体系双键转化率的影响较小,显著降低了体系的光聚合体积收缩,掺杂10 wt%MI-POSS使体系的光聚合体积收缩率降低29%. 相似文献
146.
10 mol% Cul combined with the DMEDA ligand can efficiently catalyze the N-arylation of 2-arylindoles with aryl iodides and aryl bromides in good to excellent yields. The aryl halides bearing electron-rich or electron-deficient functional groups can be well tolerated under this mild reaction conditions. 相似文献
147.
以硝酸亚铈(Ce(NO3)3·6H2O)和正硅酸四乙酯(C8H20O4Si)为前驱体,采用溶胶-凝胶法合成了系列具有大比表面积的xCeO2-(1-x)SiO2(x = 0,0.25,0.50,0.75,1)复合氧化物载体,然后浸渍活性组分Ni制得用于甲烷部分氧化制合成气的Ni催化剂。运用N2物理吸附-脱附、X射线粉末衍射、扫描电镜、紫外-可见漫反射光谱、氢程序升温还原、氨程序升温脱附和热重等手段对所得催化剂的组织结构、还原性、表面酸性和积炭行为等进行了表征;同时考察了催化剂的组成、焙烧温度和反应时间等对催化剂在甲烷部分氧化制合成气中催化性能的影响。表征结果表明,该系列Ni/CeO2-SiO2催化剂具有大比表面积,CeO2晶粒较小,NiO的分散性好且易被还原,表面酸性弱,不容易积炭。当Ce/Si摩尔比为1:1,活性组分Ni的质量分数为10%,焙烧温度为700℃时,所制备的Ni/CeO2-SiO2催化剂表现出较好的稳定性、最高的CH4转化率(~84%)和对产物CO及H2的选择性(>87%)。 相似文献
148.
Improved Polysaccharide Production in Submerged Culture of Ganoderma lucidum by the Addition of Coixenolide 总被引:2,自引:0,他引:2
Huabin Zhou Pengyang Bi Xiangting Wu Furu Huang Hailong Yang 《Applied biochemistry and biotechnology》2014,172(3):1497-1505
Polysaccharides from Ganoderma lucidum have various bioactivities and have been widely used as nutraceuticals and functional foods. Coixenolide was added into the media to enhance the production of mycelia biomass and polysaccharides in the submerged culture of G. lucidum in this work. The results showed that when a level of 0.2 % coixenolide was added at day 1, the biomass, exopolysaccharide, and intracellular polysaccharide reached 5.224, 0.222, and 0.399 g l?1, respectively, which were 1.39-fold, 2.58-fold, and 2.24-fold compared to that of control. Analysis of the fermentation kinetics of G. lucidum suggested that glucose concentration in the coixenolide-added group decreased more quickly as compared to the control group from days 3 to 9 of the fermentation process, and the polysaccharides biosynthesis were promoted at the same culture period. However, the culture pH profile was not affected by the addition of coixenolide. Enzyme activities analysis indicated that coixenolide affected the synthesis level of phosphoglucose isomerase and α-phosphoglucomutase. 相似文献
149.
以王水、氟化钾、Fe3+溶液为溶剂,对化探样品进行水浴加热分解1.5 h,经泡沫塑料吸附后,于90℃以上硫脲溶液中解吸20 min,然后采用石墨炉原子吸收光谱仪测定其中的金含量。对仪器分析条件进行了优化。金的质量分数在0.1~100.0 ng/g范围内与吸光度呈良好的线性,线性相关系数r2=0.999 3,检出限为0.100 ng/g。该方法对金标准物质测定结果的相对标准偏差为5.96%~9.25%(n=12),对国家一级标准物质进行分析,测定结果与标准值相符合。该方法满足1∶50 000化探样品中痕量金的分析要求。 相似文献
150.
In this research, we have used Fe3O4@nano-cellulose–OPO3H as magnetic bio-based nanocatalyst for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones via condensation of 2-aminobenzamide and different aldehydes. The major advantages of the present methodology are good yields, ecofriendly catalyst, and easy workup. 相似文献