检索结果-南通市图书馆

Photoinduced self-substitution of haloquinones

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 1994年第5期12卷 456-463页

作者： LIU, Zhong-Li ZHANG, Mao-Xi CHEN, Yi-Wen YANG, Li LIU, You-ChengNational Laboratory of Applied Organic Chemistry, lanzhou university, lanzhou, Gansu 730000, China National Laboratory of Applied Organic Chemistry Lanzhou University Lanzhou Gansu 730000 China

A series of novel oligo(halobenzoquinoid) compounds have been obtained from the photoinduced self-substitution of 2,5-dibromo-1,4-benzoquinone (1a), 2,6-dibromo-1,4-benzoquinone (1b), 2-chloro-1,4-benzoquinone (1c), 2-bromo-5-chloro-1,4-benzoquinone (1d), 2,3,5,6-tetrachloro-1,4-benzoquinone (1e) and 1,4-benzoquinone (1f) in the presence of N,N-dimethyl-t-butylamine (2) in acetonitrile. Dimers, trimers and/or pentamers of these haloquinones were found to be the major products.

关键词： PhotoreEtction haloquinones oligomers.

Studies on the Solvent Effect of N-Carbamoyl-N-(1-Oxyl 2,2,5,5-Tetramethyl-Pyrrolin-3-yl) Ureas

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 1990年第1期6卷 20-27页

作者： Zhang Ziyi and Wei Lulin (Department of Chemistry, university of lanzhou, lanzhou)Wang Hanqing (lanzhou Institute of Chemical Physics, Acoiemia Sinica, lanzhou)

The electron spin resonance spectra of N-carbamoyl-N-(l-oxyl-2,2,5,5-tetramethyl-pyrrolin-3-yl) urea compounds in ten solvents with different polarities were determined. It was found that the hyperfine splitting constant AN and spin density pN. as well as the energy difference between two adjacent energy levels E of different pyrroline nitroxides in the same solvent increase with the increase of electron-withdrawing α-bility of the substituted groups on the aromatic ring. There was a linear correlation between AN and Reichardt ET value, and between AN and Z value as well. Such a linear correlation was also found between solvent viscosity n and ESR rotational correlation time r. On the other hand, the correlation between T and the relative height hr of peak on high field was reverse. The results are discussed in the paper.

关键词： Solvent effect Ureas Pyrroline nitroxides

Stereoselective Synthesis of 2-(4-Hydroxyphenyl)-3-hydroxymethyl-1,4-benzodioxane-6-aldehyde—The Key Intermediate of Sinaiticin

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1999年第2期10卷 107-108页

作者： Xue Gong SHE Wen Xin GU Hua WANG Xin Fu PAN(Department of Chemistry,National Laboratory of Applied Oerganic Chemistry，lanzhou university,lanzhou 730000) lanzhou Univ Dept Chem Natl Lab Appl Organ Chem Lanzhou 730000 Peoples R China

2-(4-Hydroxyphenyl)-3-hydroxymethyl-1,4-benzodioxane-6-aldehyde 8,the key intermediate of sinaiticin 10,was synthesized in 6 step from caffeic acid 4 and 4- hydroxybenzsaldehyde *** coupling reaction is the key step.

关键词： 2-(4-Hydroxyphenyl)-3-hydroxymethyl-1 4-benzodioxane-6-aldehyde key intermediate sinaiticin synthesis

A NEW SESQUITERPENE FROM CELASTRUS ROSTHONIANUS

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1991年第12期2卷 935-936页

作者： Yong Qiang TU Department of Chemistry, lanzhou university, lanzhou, 730000

A new sesquitcrpene was isolated from Celastrus rothornianus, its structure was clucidated mainly on the basis of spectral analysis.

关键词： Office Chen A NEW SESQUITERPENE FROM CELASTRUS ROSTHONIANUS

Responding Depth of Photocatalytic Activity of TiO_2 Self-assembled Films

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2004年第4期20卷 472-474页

作者： Weichang HAO, Feng PAN, Tianmin WANG and Shukai ZHENG)Center of Materials Physics and Chemistry, School of Science, Beijing university of Aeronautics and Astronautics, Beijing 100083, ChinaDepartment of Materials Science, lanzhou university, lanzhou 730000, China Ctr. of Mat. Phys. and Chem. Sch. of Sci. Beijing Univ. of Aero. and Astron. Beijing 100083 China Dept. of Mat. Sci. Lanzhou Univ. Lanzhou 730000 China

The electrostatically self-assembly method is getting strategically important to prepare multilayer thin films. With careful choice of component materials, this method should allow for the preparation of multilayer thin films with a variety of excellent technological properties. Ti02/PSS multilayer thin films with ordered structure were prepared by electrostatic self-assembly method. UV-Vis-NIR spectrophotometer, X-ray photoelectron spectroscopy (XPS), and atom force microscopy (AFM) were used to characterize the structure and performance of the multilayer films. Because electrostatically self-assembly method allows molecular-level control over the film composition and thickness, this paper studied the responding depth of photocatalytic activity of Ti02 self-assembled films in detail.

关键词： Responding depth Titanium dioxide Photocatalytic activity Electrostatically self-assembly

An Important Rule-Jeans Rule

在线全文

学校读者我要写书评

暂无评论

紫金山天文台台刊 1996年第3期15卷 93-97页

作者： Gao Chong-yi Department of Physics,lanzhou university,lanzhou,730000,China

From theoretical physics,Jeans rule can be derived *** is applicable to the planets,satellites,asteroids and meteoroids in the solar *** condition satisfying Jeans rule,is just the necessary condition for a given spec... 详细信息

关键词： An Important Rule-Jeans Rule net

Studies on the Model Synthesis of the Brassinolide and Dolicholide Side Chains

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2003年第9期14卷 889-892页

作者： Li Zeng PENG, Feng Zhi ZHANG, Tian Sheng MEI, Yu Lin LINational Laboratory of Applied Organic Chemistry, Institute of Organic Chemistry, lanzhou university, lanzhou 730000 National Laboratory of Applied Organic Chemistry Institute of Organic Chemistry Lanzhou University

A stereoselective synthesis of brassinolide and dolicholide, which involves construction of the side chain enantiomers by a highly stereoselective aldol reaction of aldehyde 5 with the anion of α-silyloxy ketone 6 is... 详细信息

关键词： Brassinolide dolicholide side chain aldol reaction.

Stereochemical effects in mass spectra—Studies on mass spectra of epimers of podophyllotoxin and its derivatives

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 1986年第1期4卷 35-41页

作者： CHEN Yao-Zu HUA Su-Ming CHEN Nen-Yu Department of Chemistry, lanzhou university, lanzhou Department of Chemistry Lanzhou University Lanzhou

Mass spectra of thirteen epimers of podophyllotoxin and its derivatives have been exa-mined. By means of high resolution mass spectrometry, metastable ion scanning and isotope-labeling techniques, the effects of configuration of C3-OH and condensed lactone ring on the frag-mentation pattern and the relative abundanees of characteristic ions in the mass spectra of these com-pounds have been studied and rationalized.

关键词： Li Stereochemical effects in mass spectra Studies on mass spectra of epimers of podophyllotoxin and its derivatives

Carboxymethyl-β-Cyclodextrin for Chiral Separation of Basic Drugs by Capillary Elcctrophoresis

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1999年第10期10卷 831-832页

作者： Wei WANG Xiao Yun FU Yao Zu CHEN (Analytical and Testing Center, Zhejiang university. Hangzhou 310027)(State Key Laboratory of Applied Organic Chemistry, lanzhou university, lanzhou 730000) Analytical and Testing Center Zhejiang University Hangzhou 310027 China State Key Lab. of Appl. Organ. Chem. Lanzhou University Lanzhou 730000 China

Four basic drugs were separated by capillary electrophoresis (CE) usingcarboxymethyl-β-yclodextrin (CM-0-CD) as chiral selector. The effects of CM-β-CDconmptration, applied voltage. operation temperature were investigated. Under the selectedconditions. norephedrine. ofloxacin. terbutaline and chlorpheniramine were enantiomerallybaieline-separated using H3PO4-triethanolamine buffer at PH 3 containing 10, 5.5, 2. 2mmol/LCM-β-CD respectively.

关键词： Capillary electrophoresis chiral separation, carboxymethyl-β-cyclodextrin. basicdrugs.