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51.
Emil Byström Anna Nordborg Fredrik Limé Ngoc Phuoc Dinh Knut Irgum 《Journal of separation science》2010,33(11):1563-1570
A combined surface activation and “grafting to” strategy was developed to convert divinylbenzene particles into weak cation exchangers suitable for protein separation. The initial activation step was based on plasma modification with bromoform, which rendered the particles amenable to further reaction with nucleophiles by introducing Br to a surface content of 11.2 atom‐%, as determined by X‐ray photoelectron spectroscopy. Grafting of thiol‐terminated glydicyl methacrylate telomers to freshly plasma activated surfaces was accomplished without the use of added initiator, and the grafting was verified both by reduction in bromine content and the appearance of sulfur‐carbon linkages, showing that the surface grafts were covalently bonded. Following grafting the attached glydicyl methacrylate telomer tentacles were further modified by a two‐step procedure involving hydrolysis to 2,3‐hydroxypropyl groups and conversion of hydroxyl groups to carboxylate functionality by succinic anhydride. The final material was capable of baseline separating four model proteins in 3 min by gradient cation exchange chromatography in a fully aqueous eluent. 相似文献
52.
The 3',5'-bis-O-TBDMS derivative of 2'-deoxyguanosine can be converted to its O6-alkyl and O6-aryl ethers as well as to N6-substituted diaminopurine nucleosides in two simple steps. Also described is a novel, nonaqueous, one-step O6-desulfonylation method that leads to deprotection of the carbonyl moiety of 2'-deoxyguanosine. 相似文献
53.
Synthesis and Structure of Mo2NCl7 The reaction of VN with MoCl5 at 175 °C in a sealed glass ampoule yields the molybdenum(V) nitride chloride Mo2NCl7 in form of air sensitive black crystals with the triclinic space group P1¯ and a = 905.7(8); b = 975.4((6); c = 1283.4(8) pm, α = 103.13(4)°; β = 109.83(5)° und γ = 98.58(5)°. The crystal structure is built up from dinuclear units [Mo2N2Cl7]3— and [Mo2Cl7]3+, which are connected by asymmetric nitrido bridges to form endless chains. Within both dinuclear units the Mo atoms are bridged by three Cl atoms resulting in a Mo‐Mo distance of 349.2(3) pm in the unit [Mo2N2Cl7]3—. In case of [Mo2Cl7]3+, however, a shorter Mo‐Mo distance of 289.4(3) pm is observed, which can be interpreted by a single bond. Correspondingly a reduced magnetic moment of 0.95 B.M. per Mo atom is observed. 相似文献
54.
Soluble catalysts for the Juliá-Colonna asymmetric epoxidation reaction have been constructed in three different ways, using NH2-PEG-OMe as the support system: suitable solvents have been identified and it is shown that the degree of helicity of the conjugates correlates with the extent of conversion and (to a lesser extent) the enantioselectivity of epoxidation. 相似文献
55.
Nguyen Huu Dinh Hoang Thi Tuyet Lan Tran Thi Thu Trang Pham Van Hoan 《Journal of heterocyclic chemistry》2012,49(4):814-822
A novel hydrazide, 2‐methoxy‐4‐(3‐methyfuroxan‐4‐yl)‐5‐nitrophenoxyacetylhydrazine, was prepared from isoeugenoxyacetic acid. The hydrazide was condensed with aromatic aldehydes to give a series of 20 hydrazide‐hydrazones incorporating the furoxan ring. The structure of obtained compounds was determined by analytical and spectral data. It was demonstrated that the two sets of resonance signals in the 1H‐NMR and 13C‐NMR spectra of the examined hydrazide‐hydrazones are caused by EN–C(O) and ZN–C(O) conformers. The energy barriers for the conformation exchange were determined by 1H‐NMR‐measurement at various temperatures. Among seven tested hydrazide‐hydrazones, four compounds exhibit inhibition activities in vitro on human epidermis carcinoma (KB‐cell) with IC50 = 47, 68, 79, and 103 μg/mL. 相似文献
56.
Ly Dieu Ha Poul Erik Hansen Fritz Duus Hung Dinh Pham Lien‐Hoa D. Nguyen 《Magnetic resonance in chemistry : MRC》2012,50(3):242-245
Four new prenylated depsidones, oliveridepsidones A–D, were isolated from the bark of Garcinia oliveri collected in Vietnam. Their structures were elucidated using mainly NMR techniques (1H and 13C NMR, HMQC, HMBC and NOE experiments). Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
57.
58.
Hong-Jie ZhangGhee Teng Tan Vu Dinh HoangNguyen Van Hung Nguyen Manh CuongDjaja Doel Soejarto John M PezzutoHarry H.S Fong 《Tetrahedron》2003,59(2):141-148
Bioassay directed-fractionation led to the identification of litseaverticillols A-H (1-8) from the leaves and twigs of Litsea verticillata Hance. These new sesquiterpenes possess a unique skeleton that was recently designated as ‘litseane’. The structures of these compounds were determined by spectroscopic means including 1D and 2D NMR data. Structural configurations were determined by ROESY experiments. Mosher ester reactions and optical rotation measurements established the sesquiterpenes 1-8 as racemates. Isolates 1-8 inhibited HIV-1 replication in HOG.R5 cells with IC50 values ranging from 2 to 15 μg/ml (8-58 μM) while affecting the growth of HOG.R5 at concentrations 2-3-fold higher. Based on this data, structure-activity relationships can be discerned, suggesting compounds of this class are good candidates for analog production. 相似文献
59.
Itharat A Plubrukarn A Kongsaeree P Bui T Keawpradub N Houghton PJ 《Organic letters》2003,5(16):2879-2882
[structure: see text] Commonly used among ingredients in Thai traditional anticancer preparations, the rhizome of Dioscorea membranacea Pierre was found potently cytotoxic and possibly contributed to such a therapeutic effect. Bioassay-guided isolation resulted in two novel cytotoxic naphthofuranoxepins, dioscorealides A (1) and B (2), and a new 1,4-phenanthraquinone, dioscoreanone (3). The structure determination, achieved mainly by means of NMR and CD spectral and X-ray crystallographic analyses, and cytotoxicity are discussed here. 相似文献
60.
Maria Vittoria SpaneddaVu Dinh Hoang Benoit Crousse Danièle Bonnet-Delpon Jean-Pierre Bégué 《Tetrahedron letters》2003,44(2):217-219
Hexafluoroisopropanol and trifluoroethanol are found to promote imino-Diels-Alder reactions of the N-aryl aldimine 1 with alkyl vinyl ethers to afford the corresponding tetrahydroquinolines in good yields without Lewis acid under mild and neutral conditions. The reaction is also efficient in a three component process from aldehyde, amine and vinyl ethers. 相似文献