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排序方式: 共有238条查询结果,搜索用时 187 毫秒
21.
Mochona B Le L Gangapuram M Mateeva N Ardley T Redda KK 《Journal of heterocyclic chemistry》2010,47(6):1367-1371
Synthesis of a series of 2-substituted benzimidazoles was carried out for screening anti-inflammatory activities. 2-(N-benzylpyrrolyl)-benzimidazoles 9a-k were synthesized from N-benzyl-2-pyrrole carboxylic acids 8a-d and 4-substituted-1,2-phenylenediamines by cyclocondensation utilizing polyphosphoric acid (PPA) as condensing agent. The N-benzyl-2-pyrrole carboxylic acids were prepared by standard method of N-benzylation of 2-pyrrole carboxylate using NaH/DMF and appropriately substituted benzyl halides followed by alkaline hydrolysis. 相似文献
22.
Nelly Gourlaouën Dominique Florentin Andrée Marquet 《Journal of carbohydrate chemistry》2013,32(8):1219-1238
Abstract The synthesis of 5-O-[5-(pentanoic acid)]-phosphono-L-erythro-pent-2-ulose 2 was successfully achieved by coupling benzyl 5-hydroxypentanoate 9b and 1-O-benzyl-L-erythro-pent-2-ulose ethane- 1,2-diyl dithioacetal 13 with the enediol pyrophosphate 18. Compound 2 was coupled to carrier proteins, porcine thyroglobuline and bovine serum albumin and the conjugates were treated with KCN to give conjugates of the hapten 1, designed to raise catalytic antibodies. 相似文献
23.
Filter cake formation is important in groundwater and oil wells where drilling contains suspended mud particles. The accumulation of these mud particles on the borehole wall creates a pressure drop in the well. Furthermore, the migration of colloidal particles into adjacent porous rock could damage the formation and cause productivity decline. In this study, numerical solutions for pore liquid pressure variation across the cake with variable total stress and associated porosity variation are obtained. Mass equations for captured and suspended particles are averaged along the mud cake thickness, taking into account conditions on the cake surface and at the filter septum. The variability of total stress in soil consolidations problem is considered to determine the pore liquid pressure along the mud cake thickness. Then, the relation between porosity and pressure is studied to determine the mud cake porosity. Experimental data obtained by various researchers is used to compare and test the validity of numerical solutions to develop guidelines for model applications. Results show that the pore liquid pressure increases with the decrease of membrane impedance value (i.e. less pervious membrane). Also, the pressure profile has a cubic function of dimensionless cake thickness. The conclusions from the sensitivity analysis conducted in this study agree with earlier conclusions. 相似文献
24.
Maindron N Poupart S Hamon M Langlois JB Plé N Jean L Romieu A Renard PY 《Organic & biomolecular chemistry》2011,9(7):2357-2370
The synthesis and photo-physical properties of an original bis-pyridinylpyrazine chromophore efficiently sensitising europium(III) and samarium(III) are described. The corresponding lanthanide(III) complexes display in aqueous solutions a maximum excitation wavelength which is significantly red-shifted compared to the usual terpyridine-based chelates, and a valuable luminescence brightness above 2,000 dm(3) mol(-1) cm(-1) at 345 nm was obtained with a europium(III) derivative. Further functionalisation with three different bioconjugatable handles was also investigated and their ability to efficiently label a model hexapeptide was evaluated and compared. Finally, the best bioconjugatable europium(III) chelate was used in representative labelling experiments involving monoclonal antibodies and the luminescence features of the corresponding bioconjugates remained satisfactory. 相似文献
25.
Analysis of essential oils from Scutellaria orientalis ssp. alpina and S. utriculata by GC and GC-MS
Formisano C Rigano D Senatore F Piozzi F Arnold NA 《Natural product communications》2011,6(9):1347-1350
The chemical composition of the essential oils obtained from aerial parts of Scutellaria orientalis L. ssp. alpina (Boiss.) O. Schwarz and S. utriculata Labill. growing wild in Lebanon, were analyzed by GC and GC-MS. In S. orientalis ssp. alpina, strongly characterized by sesquiterpenes (41.2%) and particularly sesquiterpene hydrocarbons (31.7%), hexahydrofarnesylacetone (11.7%) was recognized as the main constituent, together with hexadecanoic acid (7.6%), caryophyllene (7.4%), caryophyllene oxide (6.8%), 4-vinylguaiacol (5.4%) and germacrene D (5.4%). S. utriculata oil was instead constituted above all by monoterpenes (42.2%), particularly oxygen containing monoterpenes (39.9%), and in this oil the main compounds were linalool (20.1%), 4-vinyl guaiacol (15.5%), alpha-terpineol (8.9%), (E)-nerolidol (8.9%) and geraniol (8.2%). 相似文献
26.
Albena Bachvarova-Nedelcheva Stancho Yordanov Reni Iordanova Irina Stambolova Angelina Stoyanova Nelly Georgieva Veronica Nemska 《Molecules (Basel, Switzerland)》2021,26(13)
TiO2 nanopowders modified by Nd and Sm were prepared using the sol-gel technique. It was found by XRD analysis that the samples containing Sm are amorphous up to 300 °C, while those with Nd preserve a mixed organic-inorganic amorphous structure at higher temperatures (400 °C). The TiO2 (rutile) was not detected up to 700 °C in the presence of both modified oxides. TiO2 (anatase) crystals found at about 400 °C in the Sm-modified sample exhibited an average crystallite size of about 25–30 nm, while doping with Nd resulted in particles of a lower size—5–10 nm. It was established by DTA that organic decomposition is accompanied by significant weight loss occurring in the temperature range 240–350 °C. Photocatalytic tests showed that the samples heated at 500 °C possess photocatalytic activity under UV irradiation toward Malachite green organic dye. Selected compositions exhibited good antimicrobial activity against E. coli K12 and B. subtilis. 相似文献
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29.
Chattaraj PK González-Rivas N Matus MH Galván M 《The journal of physical chemistry. A》2005,109(25):5602-5607
30.
Infrared spectra of the CH(3)Cl:NO complex isolated in solid neon have been investigated. Most of the vibrational modes of the complex have been detected. The weak interaction between NO and CH(3)Cl in CH(3)Cl:NO is responsible for small shifts of the vibrational mode frequencies of both CH(3)Cl and NO molecules. The measured shifts range between -3.2 and + 3.8 cm(-1). On the basis of DFT calculations, different geometries have been explored for the complex, and it has been shown that the most stable structure is of C(1) symmetry. The calculated frequency shifts match well the experimental data. 相似文献