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241.
242.
Isoindole or 1H-isoindole, where there is the possibility of tautoinerism, is too unstable to be isolated, and its existence is ascertained only by Diels-Alder addition products with maleic anhydride and N-phenylmaleinimide.1) Moreover, the systematic preparations of isoindole derivatives have not been confirmed.2) However, several successful isoindole syntheses have been realized from ortho-disubstituted benzene derivatives. For instance,3) catalytic reduction over Raney nickel of o-cyanobenzophenone gave 1-phenylisoindole, accompanied by the oxidative coupling product. We wish to report now a synthesis of an isoindole derivative (2) by the dimerization of o-tolunitrile and several reactions of the compound (2), and the physical data were also reported. 相似文献
243.
Miyado T Wakida S Aizawa H Shibutani Y Kanie T Katayama M Nose K Shimouchi A 《Journal of chromatography. A》2008,1206(1):41-44
In order to develop a high-throughput assay for nitric oxide metabolites, nitrite (NO2-) and nitrate (NO3-), in biological fluids, we have investigated the simultaneous determination of them using an electrophoretic lab-on-a-chip (microchip capillary electrophoresis, MCE) technique. In this study, in order to establish an MCE assay process without deproteinization, the addition of a zwitterionic additive into the running buffer to reduce the adsorption of protein onto the surface of channel was investigated. Initially, some zwitterionic additives were investigated by making a comparison of relative standard deviations (RSDs) of the migration times for NO2(-) and NO3(-) on capillary electrophoresis. From the results of our comparison of the RSD values, 2% (w/w) N-cyclohexyl-2-aminoethanesulfonic acid (CHES) was selected. As a result of the application of the running buffer with CHES to the MCE process, the complete separation of NO2(-) and NO3(-) in human plasma without deproteinization was achieved within 1 min. Since the RSD values of the positions of the peaks were less than 2.3%, beneficial reduction effects on MCE were suggested. When we used an internal standard method in order to correct the injection volume, the RSDs of the peak heights and areas were less than 10%, and the correlation coefficients of spiked calibration curves ranging from 0 to 350 microM were 0.999 and 0.997 for NO2(-) and NO3(-), respectively. The limits of detection (S/N=3) were 53 microM for NO2(-) and 41 microM for NO3(-). Moreover, the correlation coefficients in excess of 0.99 between the MCE method and a conventional Griess method were achieved for both NO2(-) and NO3(-). Consequently, the possibility of establishing a high-throughput assay process was obtained by utilizing 2% (w/w) CHES to reduce protein adsorption. 相似文献
244.
Yutaka Hayashibe Yasumasa Sayama Koichi Oguma 《Fresenius' Journal of Analytical Chemistry》1996,355(2):144-149
A computer-controlled flow injection system was developed for the determination of cadmium in a hydrometallurgical zinc refining process stream. An anion-exchange method in acidic potassium iodide medium was used for the on-line separation of cadmium from the matrix zinc. 1-(4-Nitrophenyl)-3-(4-phenylazophenyl)triazene (Cadion) was used as the chromogenic reagent for the spectrophotometric detection of cadmium. In order to expand the dynamic range of the flow injection - spectrophotometry, a computer-aided time-based variable-volume injection method has been employed for the introduction of the sample into the flow injection system. Samples ranging from 0.56 to 350 l can be delivered by controlling the time period of the sample introduction valve and the flow rate of the carrier solution. The system permits a throughput of 5 samples per hour. The reproducibility has been proven to be satisfactory with a relative standard deviation of less than 6.2% (sample injected: 0.56 l of 850 g Cd/ml; n=100) and 5.0% (350 l of 0.14 g Cd/ml; n=5). The determination limit was 20 g Cd/ml with 0.56 l sample injection and 0.05 g Cd/ml with 350 l sample injection (the absolute amount of cadmium injected into the system was 11 ng and 17.5 ng, respectively). 相似文献
245.
When the esters of arylboronic acids with 2,2-dimethylpropan-1,3-diol were treated with a catalytic amount of [Rh(OH)(cod)]2 in the presence of 1,3-bis(diphenylphosphino)propane and CsF in dioxane at 60 degrees C under carbon dioxide atmosphere, the benzoic acid derivatives were obtained in good yields. Reactions of alkenylboronic esters also proceeded under similar conditions to give alpha,beta-unsaturated carboxylic acids. As these boronic esters are now easily available through coupling or direct borylation reactions, this method would be a useful method for the preparation of various functionalized aryl- and alkenyl-carboxylic acids. 相似文献
246.
Tsuyoshi Ichiyanagi Naoko Sakamoto Kazutoshi Ochi Ryohei Yamasaki 《Journal of carbohydrate chemistry》2013,32(2):53-63
A chemical synthesis of Kdo was achieved via the condensation of a protected D-mannofuranose-5,6-cyclic sulfate with ethyl 1,3-dithiane-2-carboxylate, which is an efficient equivalent for installing an α-ketoester unit as a key step. 相似文献
247.