An efficient synthesis of propargylamines via C-H activation catalyzed by copper(I) in ionic liquids

A readily available copper(I) catalyst, in an ionic liquid, can effect three-component coupling of aldehydes, amines and alkynes to generate propargylamines in high yields.     

Hydrodeoxygenation of benzofuran over sulfided and reduced Ni–Mo/γ-Al2O3 catalysts: Effect of H2S

Effect of H₂S on the catalytic performance of the reduced and sulfided Ni–Mo/Al₂O₃ catalysts in hydrodeoxygenation of benzofuran is studied. The steady-state reaction experiments showed a decrease in activity for both reduced and sulfided catalysts when H₂S was introduced into the feed. The reaction conversion of benzofuran over the reduced catalyst still remained superior to that of the sulfided catalyst in the presence of H₂S, however, at high reaction temperatures, the product distribution over the pre-reduced catalyst is similar to the sulfided catalyst. The studies with temperature-programmed desorption (TPD), temperature-programmed reaction (TPRxn) and X-ray photoelectron spectroscopy (XPS) techniques showed a partial sulfidation of the reduced catalysts when exposed to H₂S under reaction conditions, however, the catalyst does not go through a complete conversion to a molybdenum sulfide phase. Instead oxygen–sulfur exchange on the surface leaves behind oxisulfide species, with catalytic activity closely resembling that of the reduced catalysts. The effect of H₂S on the reaction performance is mainly coming from the competitive adsorption between H₂S and benzofuran and the formation of SH groups with decomposition of H₂S at high temperatures.     

Novel rhodium-catalyzed reaction of thiazolidine derivatives with carbodiimides

A new, simple, and regioselective synthesis of thiazolidinimine derivatives based on the rhodium-catalyzed reaction of readily available thiazolidines with carbodiimides is described. This methodology provides direct access to a large variety of thiazolidinimine derivatives, possibly via a novel regiospecific insertion of carbodiimides into one of two ring carbon-nitrogen bonds, as well as a metal-catalyzed imine elimination process.     

Traveling waves in rational expressions of exponential functions to the conformable time fractional Jimbo–Miwa and Zakharov–Kuznetsov equations

The conformable time fractional Jimbo–Miwa and Zakharov–Kuznetsov equations are solved by the generalized form of the Kudryashov method. A simple compatible wave transformation is employed to reduce the dimension of the equations to one. The predicted solution is of the form of a rational expression of two finite series at both the numerator and the denominator. The terms of both series are of the powers of some functions having exponential expressions satisfying a particular ODE. The exact solutions are expressed explicitly in terms of powers of some exponential functions in form of rational expressions.     

Polymers of diphenylamine-2-carboxylic acid: Synthesis, structure, and properties

Polymers of diphenylamine-2-carboxylic acid are prepared by chemical oxidative polymerization in an aqueous solution of ammonium hydroxide. In accordance with the IR data, during the polymerization of diphenylamine-2-carboxylic acid in a solution of ammonium hydroxide, polymer-chain growth occurs via C-C joining into 2 and 4 positions of phenyl rings with respect to nitrogen. The distinctive feature of the polymer is the absence of quinodiimine units in its structure, even if the oxidizer is in excess. The resulting polymers are amorphous, electroactive, and thermally stable.     

Convergence and an Explicit Formula for the Joint Moments of the Circular Jacobi $$\beta $$ β -Ensemble Characteristic Polynomial

Mathematical Physics, Analysis and Geometry - Thanks to the Birman-Schwinger principle, Weyl’s laws for Birman-Schwinger operators yields semiclassical Weyl’s laws for the corresponding...     

Numerical investigation of the solution of Fisher's equation via the B‐spline Galerkin method

The Galerkin method is used with quadratic B‐spline base functions to obtain the numerical solutions of Fisher's equation which is a one dimensional reaction‐diffusion equation. To observe the effects of reaction and diffusion, four test problems related to pulse disturbance, step disturbance, super‐speed wave and strong reaction are studied. A comparison is performed between the obtained numerical results and some earlier studies. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2010     

Recent biopharmaceutical applications of capillary electrophoresis methods on recombinant DNA technology-based products

Biopharmaceuticals (recombinant technology-based products, vaccines, whole blood and blood components, gene therapy, cells, tissues, etc.,) are described as biological medical products produced from various living sources such as human, microbial, animal, and so on by manufacturing, extraction, or semi-synthesis. They are complex molecules having high molecular weights. For their safety and efficacy, their structural, clinical, physicochemical, and chemical features must be carefully controlled, and they must be well characterized by analytical techniques before the approval of the final product. Capillary electrophoresis (CE) having versatile modes can provide valuable safety and efficacy information, such as amino acid sequence, size variants (low and high molecular weight variants), charged variants (acidic and basic impurities), aggregates, N-linked glycosylation, and O-linked glycosylation. There are numerous applications of CE in the literature. In this review, the most significant and recent studies on the analysis of recombinant DNA technology-based products using different CE modes in the last ten years have been overviewed. It was seen that the researches mostly focus on the analysis of mAbs and IgG. In addition, in recent years, researchers have started to prefer CE combined mass spectrometry (MS) techniques to provide a more detailed characterization for protein and peptide fragments.     

Performance bounds on optimal fixed prices

We consider the problem of selling a fixed stock of items over a finite horizon when the buyers arrive following a Poisson process. We obtain a general lower bound on the performance of using a fixed price rather than dynamically adjusting the price. The bound is 63.21% for one unit of inventory, and it improves as the inventory increases. For the one-unit case, we also obtain tight bounds: 89.85% for the constant-elasticity and 96.93% for the linear price-response functions.