A new route to triphenylpyridines utilizing ketoximes as building blocks via cascade reactions under iron‐organic framework catalysis

Iron‐based metal–organic framework VNU‐20 was utilized as a heterogeneous catalyst for cascade reactions between ketoximes and dibenzyl ether to produce 2,4,6‐triphenylpyridines. Additionally, benzyl alcohol and (dimethoxymethyl)benzene could be used as an alternative starting materials for the transformation. The oxidant exhibited a remarkable impact on the reactions, and di‐tert‐butylperoxide was the most appropriate candidate. The VNU‐20 displayed higher efficiency than many homogeneous and heterogeneous catalysts. The catalyst was reusable for the cascade reactions without a noticeable deterioration in catalytic activity. This transformation is new, and would offer alternative routes to triphenylpyridines utilizing ketoximes as building blocks.     

Quinolone and isoquinolone alkaloids: the structural-electronic effects and the antioxidant mechanisms

Structural Chemistry - Quinolone and isoquinolone alkaloids, which were found in the plant kingdom, are now potential antioxidants. In this case study, a quantum calculated procedure utilizing the...     

Reductive heterocyclizations via indium/iodine-promoted one-pot conversion of 2-nitroaryl aldehydes, ketones, and imines

2-Nitroaryl aldehydes, ketones, and imines were reductively cyclized to 2,1-benzisoxazoles with good yields in the presence of indium and iodine in MeOH. Under a similar condition, N-(2-nitrobenzylidene)anilines were produced mixtures of 2,1-benzisoxazoles and 3-anilino-2-phenyl-2H-indazoles.     

Scheduling real-time tasks for dependability

Real-time systems are increasingly used in applications whose failure may result in large economic and human costs. Since many such systems operate in environments that are non-deterministic, and possibly hazardous, it is extremely important that the systems be dependable, namely the deadlines of tasks must be met even in the presence of particular failures. In order to enhance the dependability of a real-time system, we study the problem of scheduling a set of real-time tasks to meet their deadlines in the presence of processor failures. We first prove that the problem of scheduling a set of non-preemptive tasks on more than two processors to tolerate one arbitrary processor failure is NP-complete even when the tasks share a common deadline. Heuristic algorithms are then proposed to solve this problem. The schedules generated by the heuristic algorithms can tolerate one arbitrary processor failure in the worst case. The analysis and experimental data show that the performance of the algorithms is near-optimal.     

Cubic Identities of Theta Functions

Many remarkable cubic theorems involving theta functions can be found in Ramanujan's Lost Notebook. Using addition formulas, the Jacobi triple product identity and the quintuple product identity, we establish several theorems to prove Ramanujan's cubic identities.     

Weakly clopen functions

We introduce a new class of functions called weakly clopen function which includes the class of almost clopen functions due to Ekici [Ekici E. Generalization of perfectly continuous, regular set-connected and clopen functions. Acta Math Hungar 2005;107:193–206] and is included in the class of weakly continuous functions due to Levine [Levine N. A decomposition of continuity in topological spaces. Am Math Mon 1961;68:44–6]. Some characterizations and several properties concerning weakly clopenness are obtained. Furthermore, relationships among weak clopenness, almost clopenness, clopenness and weak continuity are investigated.     

The best choice of subsample size (M,K) in 3 stage sampling

In this paper we extend the best choice of subsample size m in the 2-stage sampling,which suggested by Mohammad(1986), to the 3-stage sampling in cases of known and of unknown cost and variance ratio. We find the subsample size m,k which ensures more than the relative efficiency 90 %. Also we see that the choice of 3-stage subsample size depends on the design parameters using in 2-stage sampling.     

Surface modification by silver coating for improving electrochemical properties of LiFePO4

LiFePO₄ is a potential candidate for the cathode material of the lithium secondary battery. Fine particle LiFePO₄ was synthesized by the simple co-precipitation method, and aqueous coating on the LiFePO₄ was tried using silver nitrate solution in order to increase electronic conductivity. Highly dispersed silver on the particles enhances the electronic conductivity and increases the capacity. The electrochemical properties of the silver coated LiFePO₄ with the various current densities are analogous to those of highly conductive LiFePO₄. The silver coating can be a promising tool to preserve the capacity even at the high current densities.