High-efficiency aminocarbonylation by introducing CO to a pressurized continuous flow reactor

Halogenated aryl carboxylic acids were efficiently converted to the corresponding dicarboxylic acid monoamides by a one-step Pd-catalyzed aminocarbonylation in a micro/meso fluidic continuous flow reactor (X-Cube) operated at high pressure and high temperature with CO gas introduction. Reaction parameters (solvent, base, catalyst, pressure, temperature) were rapidly optimized in the reactions, which required less than 2 min. The method gave improved results over comparable batch techniques and is also suited to automated parallel syntheses of compound libraries.     

Microfluidic chip analysis of outer membrane proteins responsible for serological cross-reaction between three Gram-negative bacteria: Proteus morganii O34, Escherichia coli O111 and Salmonella Adelaide O35

Bacterial strains have complex and individual antigenic structure, which provides basis for their serological identification. However, serological cross-reaction may occur when antibodies against a certain strain recognize other strains too. The molecular basis of this phenomenon is the expression of similar or identical antigenic epitopes on the surface of different bacterial cells. Such cross-reactions might harden the serological diagnosis of pathogenic bacteria. But it can be also advantageous, when antigens of non-pathogenic strains can be used in the serological examinations. Serological cross-reaction between three taxonomically different strains--Proteus morganii O34 (8662/64), Escherichia coli O111 and Salmonella Adelaide O35--have been described. It has been proven that it is based partially on the similar lipopolysaccharide structures of these pathogens. In this study the involvement of the outer membrane proteins of these strains in the serological cross-reaction is presented. Microfluidic chip technology was applied for the detection of common proteins, which provided fast and quantitative data about the proteins that might be responsible for serological cross-reaction. Two outer membrane proteins with apparent molecular mass of 36 and 41 kDa, respectively, could be detected in the profile of each strain, while individual dominating protein peaks have also appeared in the protein profiles. The presence of common protein antigens was proven by Western blotting.     

Complex Formation of Some Tetraamido-type Calix[4]arene Derivatives Detected by Vibrational Spectroscopy

Abstract

Dibenzo-14-crown-4 alcohols are shown to aggregate in chloroform by the formation of hydrogen-bonded dimers. Structural variations between crown ether alcohols significantly affect the degree of dimerization. This self-association is of relevance for understanding the complexation and extractive properties of these and related macrocycles.     

Synthesis and anion recognition studies of novel 5,5-dioxidophenothiazine-1,9-diamides

Novel 5,5-dioxidophenothiazine-1,9-diacetamide and -dibenzamide receptor molecules were prepared starting from commercially available and relatively cheap chemicals. The anion recognition properties of these two diamides were investigated using UV–vis spectroscopy. Chloride formed a simple hydrogen-bonded complex with the diacetamide receptor, while fluoride, acetate and dihydrogen phosphate deprotonated both sensor molecules. Upon titration with fluoride deprotonation occurred via the formation of [HF₂]^?, and in the case of the diacetamide receptor complexation took place alongside deprotonation.     

CE to monitor endotoxins by protein complexation

A new CE method for fast and efficient analysis of bacterial endotoxins (lipopolysaccharides) is described. It is based on the strong interaction between proteins and endotoxins. The UV absorption of the protein component in the complex is used for the detection. The electrophoretic mobility of the complex hemoglobin/endotoxin can be employed for qualitative analysis of the endotoxin. For instance, the structural differences between "smooth" and "rough" lipopolysaccharides from Salmonella minnesota (wild-type), Salmonella minnesota R595 and Shigella sonnei R562H are reflected in the electrophoretic mobilities of their hemoglobin complex.