检索结果-南通市图书馆

Iron-catalyzed selective oxidation of 5-hydroxylmethylfurfural in air:A facile synthesis of 2,5-diformylfuran at room temperature

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2015年第10期26卷 1265-1268页

作者： Chi Fang Jian-Jun Dai Hua-Jian Xu qing-xiang guo Yao Fu Anhui Province Key Laboratory of Biomass Clean Energy Department of Chemistry University of Science and Technology of China School of Medical Engineering Hefei University of Technology

An iron（Ⅲ）-catalyzed selective oxidation of 5-HMF to 2,5-DFF in air at room temperature was *** approach gives 2,5-DFF with good selectivity and yields. Additionally, a two-step process was developed for the oxidation of 2,5-DFF to 2,5-FDCA at remarkably high substrate concentrations. This work demonstrates unequivocally the great potential of iron as a cheap and earth-abundant catalyst for the development of new protocols for the conversion of biomass to value-added chemicals.

关键词： Iron Biomass Oxidation Platform molecules Sustainable chemistry

CuI-catalyzed Synthesis of Aryl Thiocyanates from Aryl Iodides

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2006年第10期17卷 1283-1286页

作者： Ye Feng WANG Yuan ZHOU Jia Rui WANG Lei LIU qing xiang guo Department of Chemistry University of Science and Technology of China Hefei 230026

An operationally simple and inexpensive catalyst system was developed for the cross coupling of potassium thiocyanate with aryl iodides by using CuI as catalyst, 1, 10-phenanthroline as ligand, and tetraethylammonium iodide as activator. The procedure is applicable for the synthesis of diverse aryl thiocyanates without any exotic, poisonous reagents.

关键词： Cross coupling reaction CuI aryl thiocyanate,Aryl Iodide 1 10-phenanthroline.

Cu-catalyzed arylation of phosphinic amide facilitated by (±)-trans-cyclohexane-1,2-diamine

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2007年第9期18卷 1033-1036页

作者： Juan Li Song Lin Zhang Chuan Zhou Tao Yao Fu qing xiang guo Department of Chemistry University of Science and Technology of China Hefei 230026 China

Cu-catalyzed cross coupling between phosphinic amides and aryl halides was accomplished for the first time by using (±)-trans-cyclohexane-1,2-diamine as the ligand. This reaction provided a novel approach for synthesizing arylated phosphinic amides. Both kinetic measurement and theoretical calculation indicated that phosphinic amides were much less reactive than amides by about 10 times in Cu-catalyzed cross coupling.

关键词： Phosphinic amide Copper Catalyst Cross coupling

Copper-mediated synthesis of N,N'-diarylhydrazines from boronic acids

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2007年第5期18卷 499-501页

作者： Ye Feng Wang Yuan Zhou Jia Rui Wang Lei Liu qing xiang guo Department of Chemistry University of Science and Technology of China Hefei 230026 China

N,N＇-Diarylhydrazines have been prepared via the reaction of N-Boc-aryl hydrazines with boronic acids mediated by copper acetate. This mild reaction condition tolerates the presence of a variety of functional groups.

关键词： Cross coupling reaction N,N'-Diarylhydrazines Boronic acids Copper acetate

One-pot Synthesis and Characterization of 13-Acetyl-9-methyl-11-oxo-8- oxa- 10,12-d iazatricyclo [7.3.1.0^2,7] trideca- 2,4,6- triene

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2006年第1期19卷 84-88页

作者： Hojatollah Salehi Qian-rong Li qing-xiang guo Hefei National Laboratory for Physical Sciences at Microscale Department of Chemistry University of Science and Technology of China Hefei 230026 China Scholarship Department Ministry of Science Research and Technology P.O. Box Tehran 15875-6185 Iran

An efficient and environmentally friendly procedure for the one-pot synthesis of 13-acetyl-9-methyl-ll-oxo-8-oxa-10,12-diazatricyclo[7.***.1.0^2,7]trideca-2,4,6-triene from salicylaldehyde, acetylacetone and urea via Biginelli condensation and intramolecular Michael-addition by using magnesium bromide as an inexpensive and easily available catalyst in a solvent-free condition is described. The structural elucidation of the product is reported by ^1H- and ^13C NMR spectra. The product can also be identified by its EI TOF mass spectrometry based on the molecular ion at m/s 246（10%） and on the fragment ions in which two nitrogen atoms are remained. Three kinds of characteristic fragmentation pathways from the molecular ion were observed. One is the loss of the OH radical to form the dihydropyrimidinone cation at m/z 229（48%）, followed by elimination of a molecular methane forming the pyrimidinone cation at m/z 213（27%）. The second is the cleavage of the C6H4OH radical, and the formation of the dihydropyrimidinone cation at m/z 153（24%）. The third one is the loss of MeC-O radical to afford the oxygen-bridged fragment ion at m/z 203（33%）.

关键词： Oxygen-bridged dihydropyrimidinone Intramolecular Michael-addition One-pot solvent-free synthesis NMR EI-TOFMS

Theoretical Studies on the Conformation of mono-6-O-p-nitrobenzoyl-β-cyclodextrin in Aqueous Solution

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2001年第7期12卷 637-640页

作者： Yong FENG Hai Ming ZHANG Lei LIU Yong Hui WANG Zhao Xiong LIANG qing xiang guo Department of Chemistry University of Science and Technology of ChinaHefei 230026

The conformation of mono-6-O-p-nitrobenzoyl-β-cyclodextrin was studied with B3LYP/6-311g**//PM3 calculations in vacuum and in water solution. It was concluded that the p-nitrobenzoyl group of the molecule should be located above the primary hydroxyls of the cyclodextrin instead of being completely enclosed by the cavity. It was proposed that the behavior might be caused by the requirement of a cis ester bond in the self-included conformation of the molecule.

关键词： cyclodextrin self-inclusion conformation driving force DFT.

Photoinduced Electron Transfer Between Mono-6-p-nitrobenzoyl-β- cyclodextrin and Adamantanamine-Cn-Co/Ni-porphyrins

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2006年第4期19卷 329-334页

作者： guo-tao Wen Man-zhou Zhu Hui-yuan Hu xiang-ming Meng Zhuo Wang qing-xiang guo Department of Chemistry University of Science and Technology of China Hefei 230025 China Provincial Key Laboratory of Research on Wastewater Treatment Technology Anhui Academy of Environmental Science Research Hefei 230051 China

Two series monot ailed porphyrins, Cobalt-5- {4- [ω- （1-adamant aneamino） alkyloxy] phenyl }- 10,15,20-triphenyl porphyrinate （CoPCnA, n=4,5,6） and Nickel-5-{4-[ω-（1-adamantaneamino）alkyloxy]phenyl}-10,15.20- triphenyl porphyrinate （NiPCnA, n=4,5,6）, were synthesized, in which the porphyrin moiety was connected to l-adamantanamine via a flexible hydrocarbon chain. The fluorescence quenching between these donor substrates and mono-6-p-nitrobenzoyl-β-cyclodextrin （NBCD） was studied in detail. Distinct fluorescence quenching occured in these supramolecular systems. This quenching was attributed to the photoinduced electron transfer （PET） inside the supramolecular assembly between the porphyrin donors and cyclodextrin acceptors. Detailed Stern-Volmer constants were measured and they were partitioned into dynamic Stern- Volmer quenching constants and static binding constants. It was demonstrated that the PET interaction between the porphyrin subunits and NBCD is indeed effective.

关键词： Photoinduced electron transfer Host-guest complex Cyclodextrin Supramolecular system Fluorescence quenching

Hartree-Fock and Density Functional Theory Studies on the Molecular Recognition of the Cyclodextrin

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1999年第12期10卷 0-0,0-0页

作者： Lei LIU Xiao Song LI qing xiang guo You Cheng LIUDepartment of Chemistry, University of Science and Technology of China, Hefei 230026) Univ Sci & Technol China Dept Chem Hefei 230026 Peoples R China

This study involves initial Hartree-Fock and Density Functional theory calculations onthe molecular recognition of the cyclodextrins. The α-cyclodextrin-acetophenone complexationsystem was investigated with PM3, HF/3-21G* and B3LYP/3-21G* methods. The results indicatedthat the inclusion orientation in which the acetyl group of the acetophenone points towards thesecondary hydroxyls of the a-cyclodextrin was preferable in energy. The steric effect wassupposed as the physical reason of such a behavior Hence, the simple rule the anti-parallelarrangement of the dipoles of the host and guest molecules in the cyclodextrin complexqtion is notgenerally applicable.

关键词： ab initio acetophenone cyclodextrin density functional theory molecular recognition

Effects of Bases on the Stabilities of Nucleoside C4'Radicals

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2003年第10期14卷 1073-1076页

作者： Bo Lin LIN, Yao FU, Lei LIU, qing xiang guo Department of Chemistry, University of Science and Technology of China, Hefei 230026 Department of Chemistry University of Science and Technology of China

C4'-H bond dissociation enthalpies of nucleosides were predicted using theoretical methods to a precision of 1-2 Kcal/mol. It was found that the stability of the C4' nucleoside radical is slightly dependent on the bas... 详细信息

关键词： Nucleoside homolysis bond energy DNA lesion substituent effect.