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1.
4H-Pyrans (4H-Pys) and 1,4-dihydropyridines (1,4-DHPs) are important classes of heterocyclic scaffolds in medicinal chemistry. Herein, an indium(III)-catalyzed one-pot domino reaction for the synthesis of highly functionalized 4H-Pys, and a model of 1,4-DHP is reported. This alternative approach to the challenging Hantzsch 4-component reaction enables the synthesis of fused-tricyclic heterocycles, and the mechanistic studies underline the importance of an intercepted-Knoevenagel adduct to achieve higher chemoselectivity towards these types of unsymmetrical heterocycles.  相似文献   
2.
Molecular Diversity - In this paper, we report the synthesis of novel hybrids 2–14 based on itaconic acid and fluoroaniline, pyridine, indole and quinoline scaffolds. Itaconic acid is a...  相似文献   
3.
Molecular Diversity - Here, we describe design and synthesis of twelve novel compounds bearing primaquine motif and hydroxy- or halogenamine linked by an urea or bis-urea spacer. Preparation of...  相似文献   
4.
We present a study on amorphous SiO/SiO2 superlattice performed by grazing-incidence small-angle X-ray scattering (GISAXS). Amorphous SiO/SiO2 superlattices were prepared by high-vacuum evaporation of 3 nm thin films of SiO and SiO2 (10 layers each) onto Si(1 0 0) substrate. After the deposition, samples were annealed at 1100 °C for 1 h in vacuum, yielding to Si nanocrystals formation. Using a Guinier approximation, the shape and the size of the crystals were obtained. The size of the growing nanoparticles in the direction perpendicular to the film surface is well controlled by the bilayer thickness. However, their size varies more significantly in the direction parallel to the film surface.  相似文献   
5.
Metal island films (MIF) are good candidates for sensors due to the strong sensitivity of the localised surface plasmon resonance to the environment refractive index. The strong near field enhancement in the vicinity of the island surface can be even higher if a metal layer (ML) is placed close to a MIF. Structures containing MIF with and without ML are prepared and sensitivities of spectrophotometric and ellipsometric features of the measurements are compared. It is shown that simple MIF is preferable for ellipsometry-based sensing and the one including ML in the case of spectrophotometric measurements.  相似文献   
6.
This paper reports strong deep-ultraviolet and visible photoluminescence (PL) of the GaN nanoparticles depending on the conversion time from Ga2O3 to GaN. Monoclinic β-Ga2O3 nanoparticles with a diameter of approximately 2.5–5.0 nm were fabricated prior to conversion to GaN. The Ga2O3 nanoparticles were converted to GaN in the tube furnace with NH3 flow at 900°C for 10, 30, 60, and 120 min. Depending on the conversion time, the converted GaN nanoparticle size became bigger with the increase of the conversion time. The characteristic GaN x-ray diffraction (XRD) peaks became bigger when the conversion time increased. The PL intensity drastically increased with the increase of the conversion time. The spectra profile completely overlapped for GaN samples converted for 10, 30, and 60 min, with the maximum peak at 390 nm. However, the PL spectrum slightly narrowed and red-shifted with the maximum peak at 400 nm for the GaN nanoparticles converted for 120 min.  相似文献   
7.
Sorafenib is a relatively new cytostatic drug approved for the treatment of renal cell and hepatocellular carcinoma. In this report we describe the synthesis of sorafenib derivatives 4a-e which differ from sorafenib in their amide part. A 4-step synthetic pathway includes preparation of 4-chloropyridine-2-carbonyl chloride hydrochloride (1), 4-chloro-pyridine-2-carboxamides 2a-e, 4-(4-aminophenoxy)-pyridine-2-carboxamides 3a-e and the target compounds 4-[4-[[4-chloro-3-(trifluoromethyl)phenyl]carbamoylamino]-phenoxy]-pyridine-2-carboxamides 4a-e. All compounds were fully chemically characterized and evaluated for their cytostatic activity against a panel of carcinoma, lymphoma and leukemia tumour cell lines. In addition, their antimetabolic potential was investigated as well. The most prominent antiproliferative activity was obtained for compounds 4a-e (IC(50) = 1-4.3 μmol·L-1). Their potency was comparable to the potency of sorafenib, or even better. The compounds inhibited DNA, RNA and protein synthesis to a similar extent and did not discriminate between tumour cell lines and primary fibroblasts in terms of their anti-proliferative activity.  相似文献   
8.
RNase (ribonuclease) mapping by nucleobase-specific endonucleases combined with mass spectrometry (MS) is a powerful analytical method for characterizing ribonucleic acids such as transfer RNAs. Typical free solution enzymatic digestion of RNA samples results in a significant amount of RNase being present in the sample solution analyzed by MS. In some cases, the RNase can lead to contamination of the high performance liquid chromatography and MS instrumentation. Here we investigate and compare several different approaches for reducing or eliminating contaminating RNase from the digested RNA sample before LC-MS analysis. Approaches using immobilized RNases were found to be most effective, with no enzyme carryover into the digested sample detected. Among the various options for immobilized RNases, we show that carbodiimide-based reactions can be used to couple RNases to carboxylic acid-terminated magnetic beads. The immobilized enzymes retain biological activity, are re-usable, and do not interfere with subsequent LC-MS analysis of the expected RNase digestion products. The use of immobilized RNases provides a simple approach for eliminating enzyme contamination in mass spectrometry-based RNase mapping experiments.  相似文献   
9.
Bimetallic islands films consisting of composite Au-Ag nanoparticles are deposited on glass substrates by electron beam evaporation. Broad tuning of the surface-plasmon resonance (SPR) characteristics can be achieved by controlling film composition, deposition temperature and post-deposition thermal annealing. Optical and structural characterization of the samples enable one to establish the link between the SPR and the morphological and compositional characteristics of nanoparticles.  相似文献   
10.
Molecular Diversity - In the present study, we report the design and synthesis of novel amide-type hybrid molecules based on anthranilic acid and quinoline or β-carboline heterocyclic...  相似文献   
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