Facile synthetic routes for the preparation of some new 4-amino-3,5-dinitropyridine derivatives have been revealed. Nitration of 2-chloropyridin-4-amine (1) as a starting material, in an unexpected one-step reaction, to give dinitrated derivatives, followed by nucleophilic substitution reactions with sodium azide, potassium fluoride, ammonia, methylamine, and 4-nitroimidazol, respectively, gave substituted 4-amino-3,5-dinitropyridine derivatives. Meanwhile, its azide derivative underwent a ring closure conversion into 7-amino-6-nitro-[1,2,5]oxadiazolo[3,4-b]- pyridine-1-oxide. It is of significance that all of the nucleophilic substitution reactions were carried out under mild conditions. 相似文献
A Bi(OTf)3-catalyed reaction of 3-aryl propargyl alcohols with sulfonamide and halogen source was firstly investigated, which provided a facile route for the synthesis of a large variety of α-halo-β-amino ketones. The key intermediates, β-amino ketones, were obtained through tandem Meyer-Schuster rearrangement reaction of propargyl alcohols and intermolecular Michael addition of α, β-unsaturated ketones and sulfonamide. Then the in situ generated α-halo-β-amino ketones underwent the base-promoted intramolecular cyclization to give diverse acyl aziridines in a one-pot fashion. These transformations are reliable on a large scale. The high yields and convenient experimental operations make it a valuable method for the construction of α-halo-β-amino ketones and acyl aziridine derivatives. 相似文献
In this paper, to better reveal the surface effect and the screening effect as well as the nonlinear multi-field coupling characteristic of the multifunctional piezoelectric semiconductor (PS) nanodevice, and to further improve its working performance, a magneto-mechanical-thermo coupling theoretical model is theoretically established for the extensional analysis of a three-layered magneto-electro-semiconductor coupling laminated nanoplate with the surface effect. Next, by using the current theoretical model, some numerical analyses and discussion about the surface effect, the corresponding critical thickness of the nanoplate, and the distributions of the physical fields (including the electron concentration perturbation, the electric potential, the electric field, the average electric displacement, the effective polarization charge density, and the total charge density) under different initial state electron concentrations, as well as their active manipulation via some external magnetic field, pre-stress, and temperature stimuli, are performed. Utilizing the nonlinear multi-field coupling effect induced by inevitable external stimuli in the device operating environment, this paper not only provides theoretical support for understanding the size-dependent tuning/controlling of carrier transport as well as its screening effect, but also assists the design of a series of multiferroic PS nanodevices.
Nanometer‐sized magnetic stirring bars containing Pd nanoparticles (denoted as Fe3O4‐NC‐PZS‐Pd) for heterogeneous catalysis in microscopic system were prepared through a facile two‐step process. In the hydrogenation of styrene, Fe3O4‐NC‐PZS‐Pd showed an activity similar to that of the commercial Pd/C catalyst, but much better stability. In microscopic catalytic systems, Fe3O4‐NC‐PZS‐Pd can effectively stir the reaction solution within microdrops to accelerate mass transfer, and displays far better catalytic activity than the commercial Pd/C for the hydrogenation of methylene blue in an array of microdroplets. These results suggested that the Fe3O4‐NC‐PZS‐Pd could be used as nanoscale stirring bars in nanoreactors. 相似文献
The authors prove that the total descendant potential functions of
the theory of Fan-Jarvis-Ruan-Witten for $D_4$ with symmetry group
$\genj$ and for $D_4^T$ with symmetry group $G_{\rm max}$,
respectively, are both tau-functions of the $D_4$
Kac-Wakimoto/Drinfeld-Sokolov hierarchy. This completes the proof,
begun in the article by Fan-Jarvis-Ruan (2013), of the Witten
Integrable Hierarchies Conjecture for all simple (ADE)
singularities. 相似文献