Chiral separation of labetalol stereoisomers in human plasma by capillary electrophoresis

A newly derivatized cyclodextrin [octakis-(2,3-diacetyl-6-sulfato)-gamma-cyclodextrin] was investigated as a chiral selector in capillary zone electrophoresis in a study of the chiral separation of labetalol stereoisomers. Heptakis(2,3-diacetyl-6-sulfato)-beta-cyclodextrin (HDAS-beta-CD) and octakis(2,3-diacetyl-6-sulfato)-gamma-cyclodextrin (ODAS-gamma-CD) were shown to be effective in separating labetalol stereoisomers. Optimal separating conditions of the four stereoisomers of labetalol were achieved with 10 mM HDAS-beta-CD and 10 mM ODAS-gamma-CD in an acidic pH buffer of low molarity. Data illustrating the effects of capillary length and cyclodextrin concentration on the separation are presented. The longer capillary length and high voltage enabled the baseline separation of all isomers in less than 15 min. The optimized method was applied to the analysis of human control plasma containing labetalol utilizing solid-phase extraction (SPE) in the 96-well format.     

A convenient approach to λ-phosphinines via interaction of phosphorylated 3-pyrrolidinocrotonitrile with 2-bromoacetophenones

The alkylation of 2-(diphenylphosphino)-3-pyrrolidin-1-ylbut-2-enenitrile with a set of bromoacetophenones has been studied. Cyclization of the phosphonium salts into 6-cyano-3-hydroxy-3-aryl-1,1-diphenyl-5-pyrrolidin-1-yl-1,2,3,4-tetrahydrophosphininium bromides under heating in the presence of catalytic amount of a base is discussed. Starting both from the acyclic and the cyclic phosphonium salts, new types of λ⁵-phosphinines have been synthesized.     

Dehydrohalogenation of ethyl halides

Unimolecular decomposition kinetics of selected ethyl halides, phenethyl halides and methoxyphenethyl halides have been investigated using high level computational chemistry methods. The phenethyl halides decompose faster than the ethyl halides due to a more electronegative chlorine atom, induced by the chloroethyl functionality as an electron-withdrawing group. 1-Chloro-2-(methylthio)ethane exhibits faster dehydrochlorination than that of chloroethane/1-chloro-2-methoxyethane, owing to more polarisable C?H and C?Cl bonds in the transition structures. Calculations suggest that electronic factors rather than anchimeric assistance influence the dehydrochlorination reactions.     

Influence of the synthesis parameters on the thermal behavior of some ZnO–starch composites

Ten ZnO–starch composites were synthesized using a simple precipitation methodology. The IR spectroscopy and XRD investigations reveal the presence of amorphous starch and crystalline ZnO. The obtained composites present a spherical morphology, 5–8 spheres being interconnected into aggregates. The thermal analysis demonstrates that starch decomposition and ZnO thermally induced nucleation and crystal growth depending on the synthesis parameters such as starch processing (dissolution or gelatinization), reaction temperature (80, 90, and 100 °C), reaction time (15 min or 6 h), and applied treatments (heating or ultrasound irradiation).     

SYNTHESIS OF NOVEL AMINOPHOSPHONIC DERIVATIVES OF BENZO-15-CROWN-5 ETHER

Synthesis of new aminomethylphosphonic acids containing benzo-15-crown-5 ether, is described. These compounds were obtained from the 4′-formylbenzo-15-crown-5 by a sequence of reactions, which afforded 4′-(aminomethylphosphono)-benzo-15-crown-5 and its N-benzyl derivative in high yields.     

Effect of isomerization on the performance of aromatic hydrogen storage systems possessing different condensation extents

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Platinum-containing catalyst supported on a metal-organic framework structure in the selective oxidation of benzyl alcohol derivatives into aldehydes

The platinum catalyst supported on the metal-organic framework structure MOF-5 is usable in the selective oxidation of vanillyl and piperonyl alcohols into the corresponding aldehydes.     

Highly stereo- and regioselective synthesis of a phenylene–silylene–vinylene polymer via ruthenium-catalyzed polycondensation

[RuCl₂(CO)₃]₂ catalyzed cross-coupling polycondensation of 1,4-bis(vinyldimethylsilyl)benzene (A) appears to be a new, very efficient, method for highly stereo- and regioselective synthesis of phenylene–silylene–vinylene polymers (B).