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51.
Darensbourg DJ Maynard EL Holtcamp MW Klausmeyer KK Reibenspies JH 《Inorganic chemistry》1996,35(9):2682-2684
52.
53.
5-Methyl-4-phenyl-2-styryipyridine has been oxidized to 5-methyl-4-phenylpyridinie-2-carboxylic acid. The decarboxylation of this acid has given 3-methyl-4-phenylpyrldine. To prove the structure of -(5-methyl-4-phenyl-2-pyridyl)acetophenone, it has been converted into 2, 5-dimethyl-4-phenylpyridine. The reaction of benzyl chloride with the lithium derivative of 2, 5-dimethyl-4-phenylpyridine has been studied. 3,7-Dimethyl-2-azafluorene has been obtained from 2,5-dimethyl-4-p-tolylpyridine. 相似文献
54.
Carrillo-Marquez T Caggiano L Jackson RF Grabowska U Rae A Tozer MJ 《Organic & biomolecular chemistry》2005,3(22):4117-4123
Two distinct routes to beta-cycloalkylalanine derivatives have been developed. The first route employs the reaction of the iodoalanine-derived zinc-copper reagent 2 with cycloalk-1-en-3-yl phosphates, and the second uses the palladium-catalysed coupling of the iodoalanine-derived zinc reagent 1 with cycloalkenyl triflates; in each case, catalytic hydrogenation of the unsaturated product leads to the protected beta-cycloalkylalanine. The latter route allows access to a range of cycloalkyl derivatives, with ring sizes of 5-8. beta-(1-Methyl-1-cyclohexyl)alanine may be prepared using reaction of the zinc-copper reagent 2 with 3-methyl-2-cyclohexenyl chloride, followed by hydrogenation. The corresponding cyclopentyl derivative may be prepared by reaction of the same zinc-copper reagent 2 with diethyl geranylphosphate, followed by ring-closing metathesis and hydrogenation. 相似文献
55.
A response equation for conductivity detection in ion chromatography has been derived. This equation is applicable to non-suppressed ion chromatography using both fully ionised and partially ionised eluents. A prime assumption of this equation is that when partially ionised eluents are used (such as benzoic acid), both the ionised and neutral components of the eluent species contribute to the detector response of anionic analytes. Experimental evidence is provided to support this assumption in that pH changes accompanying the elution of an analyte have been measured. These pH changes are proportional to the concentration of analyte injected onto the column, in accordance with predictions from the response equation. Furthermore, it is shown that protonated eluents (such as benzoic acid) give more sensitive detection than equivalent ionised eluents (such as potassium benzoate) and the signal enhancement achieved using a protonated eluent species is in accordance with theory. 相似文献
56.
The reactions of benzocyclic ketones and α-ketoacids as carbonyl components in the Biginelli reaction were investigated. These unusual Biginelli substrates furnished novel drug-like dihydropyrimidinone scaffolds suitable for further elaboration. 相似文献
57.
The mode of action of the secondary metabolite chlorofusin, which antagonises the interaction between p53 and MDM2, involves direct binding to the N-terminal domain of MDM2. 相似文献
58.
Smith BD Soellner MB Raines RT 《Langmuir : the ACS journal of surfaces and colloids》2005,21(1):187-190
Intact RNA and DNA are of central importance to biochemical research and biotechnology. The preservation of these nucleic acids requires the absence of nuclease activity. Here, radical-mediated polymerization of vinylsulfonate on resin and glass surfaces is shown to produce a high-density poly(vinylsulfonate) coating that sequesters ribonucleases from aqueous solutions quickly and completely. The adsorptive efficacy of this coating exceeds that of other known coatings by > or =10(7)-fold. Surfaces coated with poly(vinylsulfonate) could be used to maintain the integrity of ribonucleic acids in a variety of contexts. 相似文献
59.
Carter DL Draper MC Peterson RN Shah DO 《Langmuir : the ACS journal of surfaces and colloids》2005,21(22):10106-10111
At the end of the final spin cycle of the laundry process, the residual moisture content (RMC) of fabric is directly related to the dynamic surface tension of the residual water in the fabric. The LaPlace equation for capillary rise predicts that the capillary rise of solutions in a capillary is proportional to the surface tension at the air-liquid interface. If fabric can be considered to be a large ensemble of capillaries due to interfiber spacing, then the RMC of fabrics will be directly related to the surface tension of residual solution in the fabric. The use of a tailored rinse additive has the potential to decrease the surface tension of solution significantly, thus leading to a decrease in the residual water content of the fabric. It is expected that as the surfactant concentration increases the surface tension decreases. Hence, the RMC of fabrics must decrease with increasing surfactant concentration. However, a peak is observed in the RMC of fabrics before the critical micelle concentration (CMC) is reached. Prior to the CMC, it is proposed that a sudden adsorption of surfactant is occurring on the fabric surface leading to a decrease in bulk monomer concentration. The decrease in free monomer concentration should result in an increase in the equilibrium surface tension of the residual solution leading to a concomitant increase in RMC. Because the dynamic surface tension is measured on a short time scale (on the order of milliseconds), there will be less adsorption of monomer onto the newly created air-liquid interface of the bubbles during the measurement process. This decrease in adsorption should lead to a pronounced increase in the dynamic surface tension. This indeed was observed. The RMC correlates very well with the dynamic surface tension of the residual solution. 相似文献
60.
The scope of reductive decyanation and spiroannulation reactions has been expanded to include secondary electrophiles for potentially useful transformations. Secondary phosphates and chlorides, as well as terminal epoxides, cyclize in a stereospecific fashion. Both endo and exo modes of cyclization were observed with terminal epoxides. 相似文献