Functionalized SBA-15 (immobilization of Pd on the modified SBA-15) has been used as an efficient catalyst for the preparation of spiroindolines by multi-component reactions of isatins, cyclic-1,3-diketones, and 6-amino-1,3-dimethyluracil under ultrasonic irradiation in water. The catalyst has been characterized by X-ray diffraction spectroscopy (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), N2 adsorption analysis, temperature-programmed desorption (TPD), and thermogravimetric analysis (TGA). The advantages of this method include the reusability of the catalyst, low catalyst loading, excellent yields in short reaction times and easy separation of products, and use of ultrasonic irradiation as a valuable and powerful technology.
Luciferin regenerating enzyme (LRE) contributes to in vitro recycling of d ‐luciferin to produce persistent and longer light emission by luciferase. Luciferin binding domains I and II among LREs regarded as potential candidates for luciferin‐binding sites. In this study, for the first time, amino acids T69, G75 and K77 located at luciferin binding domain I of LRE from L. turkestanicus (T‐LRE) substituted by using site‐directed mutagenesis. Single mutant T69R increased luciferase light output more than two‐fold over a longer time in comparison with a wild‐type and other mutants of T‐LRE. Nevertheless, double mutant (K77E/T69R) increased the amount of bioluminescent signal more than two‐fold over a short time. In addition, G75E, K77E and G75E/T69R mutants did not improve luciferin–luciferase in vitro bioluminescence. Based on our results, addition of K77E/G75E and K77E/G75E/T69R mutants caused intermediate changes in bioluminescence from in vitro luciferin–luciferase reaction. These findings indicated that the amino acids in question are possible to be located within T‐LRE active site. It may also be suggested that substituted Arg69 (Arg218) plays an important role in luciferin binding and the existence of Gly75 as well as Lys77 is essential for T‐LRE which has already evolved to have different functions in nature. 相似文献
We report on the ground state of models for strongly correlated one-dimensional Fermi systems by means of theoretical studies of two-component atomic Fermi gases in highly anisotropic harmonic traps. In this context, we consider (i) the Gaudin-Yang model for a Luttinger liquid with repulsive interactions, including an analysis of the emergence of Wigner molecules in the 2kF → 4kF crossover, and (ii) the lattice Hubbard model yielding Luttinger liquid and Mott insulator or band-insulator phases for repulsive interactions and the Luther-Emery phase for attractive interactions, including in the former case an analysis of the role of disorder. Our calculations use novel versions of density and spin-density functional theory and a density-matrix renormalization-group technique. We also discuss preliminary results and future perspectives in the study of nonsymmetric two-component Fermi gases. 相似文献
Summary. The nitration of aromatic compounds was carried out in the presence of divanadium-substituted molybdophosphoric acid, H5PMo10V2O40, as catalyst and a mixture of nitric acid and acetic anhydride as nitrating agent. In the presence of this heteropolyacid
the ortho- and para-nitro compounds were obtained in good to excellent yields under mild reaction conditions. 相似文献
The nitration of aromatic compounds was carried out in the presence of divanadium-substituted molybdophosphoric acid, H5PMo10V2O40, as catalyst and a mixture of nitric acid and acetic anhydride as nitrating agent. In the presence of this heteropolyacid
the ortho- and para-nitro compounds were obtained in good to excellent yields under mild reaction conditions. 相似文献
Biologically active pyrano[2,3-d]pyrimidine derivatives were efficiently synthesized in excellent yields by a three-component, one-pot condensation reaction of malononitrile, benzaldehydes, and barbituric acid using a catalytic amount of Zn[(L)proline]. 相似文献
In this study, the production methods and the applications of 72As are reviewed with special attention to the feasibility of the cyclotron production of 72As. TALYS-1.4 and ALICE/ASH codes were employed to illustrate the formation of the 72As via natGe(p, xn)72As, 72,73,74Ge(p, xn)72As, 72Ge(d, 2n)72As, and 69Ga(α, n)72As reactions. Hybrid model and geometry dependent hybrid model were used in ALICE/ASH code to calculate the pre-equilibrium neutron-production cross sections. The excitation functions of the reactions were taken from the TENDL-2011 database and compared with the reported experimental measurement. The equilibrium and pre-equilibrium effects on the reactions were also discussed. An optimum energy range and the level of impurities for each reaction were determined. The 72As production yield was evaluated with concentration on the excitation function calculations and the stopping powers of the projectiles in the targets. 相似文献
Summary. Cupric sulfate pentahydrate was found to be an efficient catalyst for the protection of aldehydes as 1,1-diacetates in high
yields in a solvent-free system at room temperature. Ketones are not affected under these reaction conditions. 相似文献
Clinoptilolite-supported iron(III) nitrate (clinofen) ensures fast and efficient regeneration of carbonyl compounds from the
corresponding oximes.
Published in Russian in Zhurnal Organicheskoi Khimii, 2009, Vol. 45, No. 6, pp. 876–877.
The text was submitted by the authors in English. 相似文献