Effets de micelles cationiques sur l'hydrolyse alcaline d'acetanilides a groupe acyle active par des substituants electro-attracteurs

Micellar effects of CTAB upon the alkaline hydrolysis of CF₃-CO-N(CH₃)C₆H₅, CHCl₂-CO-N(CH₃)C₆H₄X and CH₂Cl-CO-N(CH₃)C₆H₄X, (X=p-OCH₃H,p-Cl) are reported. Variations of k_obs, and of kinetic order of the reaction with respect to HO^? ion, are interpreted as an acceleration of HO^?-catalyzed steps, and a decrease of catalysis by water for decomposition of tetrahedral intermediates; these two effects oppose each other in HO^? and H₂O catalyzed steps. Differences between micellar and DMSO effects suggest a very small local concentration of HO^? ions in micelles.     

Furo- and thieno-fused 1,3-diazepine-4,6-diones

We report the first preparation of furo- and thieno-fused 1,3-diazepine-4,6-dione derivatives starting from ethyl 2-(2-methoxy-2-oxoethyl)-3-furancarboxylate and -thiophencarboxylate. The ester functionalities connected to the hetero-ring were converted regiospecifically into the desired amides. The ester groups attached to the methylene unit were converted into isocyanates via Curtius rearrangement. The ring-closure reaction was performed in the presence of lithium bis(trimethylsilyl)amide at room temperature to give furo- and thieno-fused diazepinone derivatives.     

On almost periodic processes in impulsive competitive systems with delay and impulsive perturbations

In the present paper we investigate the existence of almost periodic processes of ecological systems which are presented with the general impulsive nonautonomous Lotka–Volterra system of integro-differential equations with infinite delay. The impulses are at fixed moments of time, and by using the techniques of piecewise continuous Lyapunov’s functions, new sufficient conditions for the global exponential stability of the unique positive almost periodic solutions of these systems are given.     

A model of longitudinal dispersion in non–homogeneous porous media

This paper is concerned with a model of the longitudinal dispersion of a set of tagged particles in a flow through nonhomogeneous stratified porous media. The model is a particular homogeneous Markov jump process, the successive states visited forming a non-homogeneous Poisson process. The passage time of alevel x of this Markov process is an additive stochastic process.This property is used to evaluate the general form of the longitudinal concentration function of the tagged particles in the flow.     

A class of transformed Markov processes

This paper considers some properties of a class of transformed Markov processes. The analogy with Whittle's relaxed Markov process is pointed out. Some applications of the transformed Markov processes to queueing networks are described     

Almost periodic solutions for impulsive neural networks with delay

In the present paper the problems of existence and uniqueness of almost periodic solutions for impulsive cellular neural networks with delay are considered.     

Neue Methode zur Bestimmung von Riboflavin im Harn

Ohne Zusammenfassung

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New method for the determination of riboflavine in urine

     

Scattering of kinks of the sinh-deformed $$\varphi ^4$$ model

We consider the scattering of kinks of the sinh-deformed \(\varphi ^4\) model, which is obtained from the well-known \(\varphi ^4\) model by means of the deformation procedure. Depending on the initial velocity \(v_\mathrm {in}\) of the colliding kinks, different collision scenarios are realized. There is a critical value \(v_\mathrm {cr}\) of the initial velocity, which separates the regime of reflection (at \(v_\mathrm {in}>v_\mathrm {cr}\)) and that of a complicated interaction (at \(v_\mathrm {in}<v_\mathrm {cr}\)) with kinks’ capture and escape windows. Besides that, at \(v_\mathrm {in}\) below \(v_\mathrm {cr}\) we observe the formation of a bound state of two oscillons, as well as their escape at some values of \(v_\mathrm {in}\).     

Synthesis of Furo[2,3‐d]pyridazin‐4(5H)‐one and Its N(5)‐Substituted Derivatives

We report the efficient preparation of furo[2,3‐d]pyridazin‐4(5H)‐one and its N‐substituted derivatives starting from methyl 2‐methylfuran‐3‐carboxylate. The Me group was converted to the aldehyde group, which was then condensed with hydrazine derivatives. Then, the ester functionalities were hydrolyzed to the corresponding acids, followed by treatment with SOCl₂ to give N‐substituted furopyridazinone derivatives.