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The synthesis of novel imidazo[4,5-c]pyridines 11-13 and imidazo[4,5-b]pyridines 18-20 is described using 2 as the starting material. The synthesis is generally applicable for the introduction of a wide variety of substituents. 相似文献
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Alvaro S. de Sousa Denzel Sannasy Manuel A. Fernandes Helder M. Marques 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(10):o383-o386
The title macrocyclic amino alcohol compound, C14H30N4O, is investigated as a solid‐state synthon for the design of a self‐assembled tubular structure. It crystallizes in a helical column constructed by stereospecific O—H...N and N—H...N interactions. The hydrogen‐bonding interactions, dependent upon macrocyclic ring helicity and molecular conformation, link R,R and S,S enantiomers in a head‐to‐tail fashion, forming a continuous hydrophilic inner core. 相似文献
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Fellner FA Fellner C Wutke R Lang W Laub G Schmidt M Janka R Denzel C Bautz W 《Magnetic resonance imaging》2000,18(5):575-585
The aim of this article was to obtain initial experiences with fluoroscopically triggered contrast-enhanced (CE) 3D MR DSA with elliptical centric k-space order and 3D time-of-flight (TOF) turbo MRA of the carotid arteries. In this prospective study we examined 16 consecutive patients with suspicion of atherosclerotic disease involving the carotid arteries. Ultrasound was available in all, x-ray angiography in 12, surgical correlation in 9, and intraoperative x-ray angiography in 4 patients. All examinations were done on a 1.5 T unit applying: transverse plain 3D TOF turbo MRA and coronal CE MRA with fluoroscopic triggering. Combining head and neck array coils allowed the visualization of supraaortic arteries from the aortic arch to the circle of Willis. MRA results (maximum intensity projections) were compared with x-ray angiography, ultrasound, and inspection of endarterectomy specimens. Volume rendering was performed in selected cases additionally. Agreement between CE MRA, 3D TOF turbo MRA and x-ray angiography regarding stenoses of the internal and external carotid artery was very good. CE MRA was able to detect correctly intracranial stenoses, but delineation of the aortic arch and proximal common carotid arteries was sometimes reduced. Volume rendering was suited for visualization of MRA images providing a realistic three-dimensional impression. In conclusion, high-resolution fluoroscopically triggered CE MRA as non-invasive technique is another important step on the way to replace invasive x-ray angiography for the evaluation of atherosclerotic carotid artery disease. High resolution 3D TOF turbo MRA might be a helpful adjunct to increase the diagnostic reliability for the carotid bifurcation. 相似文献
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The synthesis of a number of new 1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid derivatives is described. Most of these compounds have either an alkoxy or a basic substituent in position 4. 相似文献
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S. Korhammer H.-D. Isengard N. Langer E. Denzel B. Markert H. Muntau R. Herzig Ph. Quevauviller 《Analytical and bioanalytical chemistry》2000,368(7):664-668
The determination of the residual water content by thermal methods and especially by Karl Fischer titration in a candidate reference material of the European Commission (candidate CRM 679 cabbage powder) is described and discussed. 相似文献
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Wei MY Leon LJ Lee Y Parks D Carroll L Famouri P 《Journal of colloid and interface science》2011,356(1):182-189
Development of the nanodevice that myosin-coated beads "walk" on actin filaments (F-actin) tracks for in vitro nanotransportation was hindered due to the difficulty of assembling large-area well-orientated F-actin tracks on the surface. In this work, we present a selective attachment of F-actin with controlled length on a patterned surface by employing biotinylated capped protein gelsolin as intermediate anchoring bridge. A patterned streptavidin layer was formed via coupling with a biotin layer that photo-actively attached to an amine-functionalized glass surface. The patterned film was found stable and homogenous compared to that obtained by microcontact printing method, according to the profiling with fluorescence microscopy. By a secondary blocking process, non-specific binding of F-actin to the patterned surface through electrostatic adsorption can be resisted. The length variation of F-actin as a function of gelsolin concentration was also investigated, implying that F-actin is appropriately of 2.5 μm in average length once F-actin/gelsolin molar ratio is 4:1. Finally, the selective attachment of F-actin was well characterized with quantifying the number of attached F-actin per unit area in the patterned areas over that in blocked areas. The density of F-actin was estimated at c.a. 2 μm(2) per actin filament molecule so that the distance between one another actin filament is estimated as c.a. 1.41-1.97 μm. The unique properties of F-actin, e.g. well flexibility or electrical conductivity, make it feasible to lay them down and form unidirectional aligned tracks by fluidic flow or electrical field. This may open a possibility for the long-distant movement of myosin-coated beads, offering a novel discipline for the development of micro-biochip in vitro. 相似文献
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Korhammer S Isengard HD Langer N Denzel E Markert B Muntau H Herzig R Quevauviller P 《Fresenius' Journal of Analytical Chemistry》2000,368(7):664-668
The determination of the residual water content by thermal methods and especially by Karl Fischer titration in a candidate reference material of the European Commission (candidate CRM 679 cabbage powder) is described and discussed. 相似文献
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Deshpande PP Ellsworth BA Buono FG Pullockaran A Singh J Kissick TP Huang MH Lobinger H Denzel T Mueller RH 《The Journal of organic chemistry》2007,72(25):9746-9749
An efficient and practical process to generate beta-C-arylglucoside derivatives was achieved. The process described involves Lewis acid mediated ionic reduction of a peracetylated 1-C-aryl methyl glucoside derived from the addition of an aryl-Li to selectively protected delta-D-gluconolactone. The reduction of the 2-acetoxy-1-C-oxacarbenium ion intermediates proceeds with a high degree of selectivity to give beta-C-arylglucosides without 2-acetoxy group participation. Furthermore, during the reduction process we also identified an unprecedented critical role of water. By changing from the usual benzyl ether protecting groups because of cost and chemical compatibility concerns, the new process is made additionally efficient and highly selective. 相似文献
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