Measurement of the relative branching fraction of upsilon(4S) to charged and neutral B-meson pairs

We analyze 9.7x10(6) B_B pairs recorded with the CLEO detector to determine the production ratio of charged to neutral B-meson pairs produced at the Upsilon(4S) resonance. We measure the rates for B0-->J/psiK((*)0) and B+-->J/psiK((*)+) decays and use the world-average B-meson lifetime ratio to extract the relative widths f(+-) / f(00) = gamma(Upsilon(4S)-->B+B-) / gamma(Upsilon(4S)-->B0 B-0)) = 1.04+/-0.07(stat)+/-0.04(syst). With the assumption that f(+-)+f(00) = 1, we obtain f(00) = 0.49+/-0.02(stat)+/-0.01(syst) and f(+-) = 0.51+/-0.02(stat)+/-0.01(syst). This production ratio and its uncertainty apply to all exclusive B-meson branching fractions measured at the Upsilon(4S) resonance.     

Trapping of radical intermediate in reaction of sulphonates with sodium iodide/zinc/dme. Total frontier orbital control of stereoselectivity in ring closure.

Reductive cyclization has been shown to accompany reduction on NaI/Zn/DME treatment of sulphonates of γ,δ- unsaturated alcohols. Stereoselectivity is due to FMO control with axial extension of SOMO of cyclohexyl radical playing a crucial role.     

Laser-ablation rates measured using x-ray laser transmission

The rate of laser ablation at irradiances of approximately 2 x 10{14} W cm{-2} of solid iron has been measured using the transmission of a neonlike zinc x-ray laser at 21.2 nm through thin iron targets. Ablated iron becomes transparent to the x-ray laser flux, enabling the thickness of unablated material and hence the rate of ablation to be measured from time resolved x-ray laser transmission.     

Validation of an LC-MS/MS method for the quantitative determination of mavoglurant (AFQ056) in human plasma

A simple, sensitive, and selective liquid chromatography/tandem mass spectrometry method was validated for the identification and quantification of mavoglurant (AFQ056) in human plasma. The chromatographic separation was performed using a Cosmosil 5 C18 (150?×?4.6 mm, 5 μm) column at 40?±?0.5 °C with a mobile phase consisting of acetic acid in water (0.1 %, v/v)/methanol (10:90, v/v) with a flow rate of 1.0 mL/min followed by quantification with tandem mass spectrometry, operating with electrospray ionization in positive ion mode and applying multiple reaction monitoring. The validated method described in this paper presents high absolute recovery with precision and accuracy meeting the acceptance criteria. The method was precise and accurate for 2- and 10-fold dilution of samples. The method was validated using sodium heparin as specific anticoagulant, and the anticoagulant effect was tested by lithium heparin and K₃EDTA. The method was successfully cross-validated between two bioanalytical sites. The method was specific for mavoglurant within the given criteria for acceptance (apparent peak area at the retention time of mavoglurant in zero samples was less than 20 % compared with the mean peak area at LLOQ) in human plasma. The method was fully validated for the quantitative determination of mavoglurant in human plasma between the range of 2.00 and 2,500 ng/mL.     

SYNTHESIS OF NOVEL SULPHONAMIDES AND EVALUATION OF THEIR ANTIBACTERIAL EFFICACY

4-(4′-sulphanilyl)-1-phenyl pipearzine (2) has been prepared by ther reaction of N-acetyl sulphanilyl chloride (ASC) with 1-phenyl piperazine followed by the hydrolysis of the product by ethanolic HCl. The hydrolyze product on facile condensation reaction with aromatic aldehydes yields Schiff bases/anils/azomethines (3a–h). These anils on cyclo condensation reaction with chloro acetyl chloride and thio glycolic acid (mercapto acetic acid) yields 2-azetidinones and 4-thiazolidinones respectively. Biological screening of the prepared compounds have been screened on some strains of bacteria.     

5‐Mercapto‐1,3,4‐thiadiazole‐2(3H)‐thione: Synthesis and Structure of Alkylated Derivatives

The observed structure of 1,3,4‐thiadiazolidine‐2,5‐dithione (also known as 2,5‐dimercapto‐1,3,4‐thiadiazole) has been previously reported in three different tautomeric forms including —dithiol and—dithione. This report examines the relative stability of each form and also reports synthesis and characterization of the structures of mono‐alkylated and di‐alkylated forms of 5‐mercapto‐1,3,4‐thiadiazole‐2(3H)‐thione. The methods of X‐ray crystallography, NMR spectroscopy, and ab initio electronic structure calculations were combined to understand the reactivity and structure of each compound.     

Simultaneous, sequential quantitative achiral-chiral analysis by two-dimensional liquid chromatography

In general, chromatographic analysis of chiral compounds involves a minimum of two methods; a primary achiral method for assay and impurity analysis and a secondary chiral method for assessing chiral purity. Achiral method resolves main enantiomeric pairs of component from potential impurities and degradation products and chiral method resolves enantiomeric pairs of the main component and diastereomer pairs. Reversed-phase chromatographic methods are preferred for assay and impurity analysis (high efficiency and selectivity) whereas chiral separation is performed by reverse phase, normal phase, or polar organic mode. In this work, we have demonstrated the use of heart-cutting (LC-LC) and comprehensive two-dimensional liquid chromatography (LC × LC) in simultaneous, sequential achiral and chiral analysis and quantitation of minor, undesired enantiomer in the presence of major, desired enantiomer using phenylalanine as an example. The results were comparable between LC-LC and LC × LC with former offering better sensitivity and accuracy. The quantitation range was over three orders of magnitude with undesired D-phenylalanine detected at approximately 0.3% in the presence of predominant, desired L-phenylalanine (99.7%). The limit of quantitation was comparable to conventional high-performance liquid chromatography. A reversed-phase C18 achiral column in the primary and reversed-phase Chirobiotic Tag chiral column in the secondary dimension were used with a compatible mobile phase.