Synthesis of isomeric 2-oxazolidinones from (1<Emphasis Type="Italic">R</Emphasis>,2<Emphasis Type="Italic">R</Emphasis>)-and (1<Emphasis Type="Italic">S</Emphasis>,2<Emphasis Type="Italic">S</Emphasis>)-2-amino-1-(4-nitrophenyl)-1,3-propanediols

A synthesis is reported for (4R,5R)-and (4S,5S)-4-hydroxymethyl-5-(4-nitrophenyl)oxazolidin-2-ones and (1′R,4R)-and (1′S,4S)-4-[hydroxy(4-nitrophenyl)methyl]oxazolidin-2-ones from (1R,2R)-and (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediols. The effect of the experimental conditions on the formation of these compounds was studied. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1562–1570, October, 2007.     

Stereochemical Features of the Condensation of Lithiated (<Emphasis Type="Italic">S</Emphasis>)-<Emphasis Type="Italic">N,N</Emphasis>-Dimethyl-1-phenylethylamine with <Emphasis Type="Italic">o</Emphasis>-Methoxybenzophenones

The condensation of lithiated (S)-N,N-dimethyl-1-phenylethylamine with o-methoxybenzophenones occurs in a nonstereoselective fashion due to possible coordination of lithium not only at the carbonyl group but also at the oxygen atom of the ortho-methoxy group.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 4, 2005, pp. 567–570.Original Russian Text Copyright © 2005 by Dem’yanovich, Shishkina, Gritsyuk, Potekhin, Chesnova, Ashkinadze.     

<Emphasis Type="Italic">tert</Emphasis>-Butyl (2<Emphasis Type="Italic">S</Emphasis>)-(<Emphasis Type="Italic">p</Emphasis>-tolylsulfonyloxy)propionate — a suitable reagent for the direct alkylation of indole derivatives

A new method is proposed for the synthesis of indole derivatives containing a chiral substituent at the nitrogen atom, which includes the direct alkylation of indole derivatives with tert-butyl (2S)-(p-tolylsulfonyloxy)propionate, obtained from commercial ethyl (S)-lactate with subsequent conversion to the corresponding p-toluenesulfonyloxy derivative by hydrolysis, and esterification. Dedicated to Academician B. A. Trofimov on his 70^th birthday. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, 1391–1398, September, 2008.     

Enantioselective analysis of (<Emphasis Type="Italic">R</Emphasis>)- and (<Emphasis Type="Italic">S</Emphasis>)-carvedilol in human plasma by high-performance liquid chromatography

Summary An HPLC column-switching method has been developed and validated for the enantioselective determination of (R)- and (S)-carvedilol in human plasma. Sample preparation was performed either off-line, by extraction with trichloromethane and back-extraction into 0.01m aqueous citric acid which was injected on to a LiChrosorb RP 8 column, or on-line, by injecting diluted (0.1m formic acid) plasma on to a LiChrosorb ADS column. In both instances separation was performed by gradient elution and on-line transfer of the fraction containing, the carvedilol on to an enantioselective Teicoplanin column. The enantiomers of carvedilol were separated isocratically by use of methanol-acetonitrile-triethylammonium acetate, 70:30:0.05 (v/v/w), as mobile phase. With fluorescence detection the limits of quantitation were 0.30 ng mL⁻¹ for (R)-carvedilol and 0.26 ng mL⁻¹ for (S)-carvedilol; these were sufficient to enable investigation of the effect of exercise on plasma concentrations of (R)- and (S)-carvedilol after oral administration of either the racemate or the pure enantiomers. Although the operating conditions were optimized for sample preparation by on-line deproteination on a LiChrospher RP 18 ADS column, the complete method was insufficiently rugged for analysis of large numbers of plasma samples—the enantioselectivity of the Teicoplanin column deteriorated too rapidly because of the transfer of enantioselectivity-poisoning interferences which could not be suppressed sufficiently. In contrast the liquid-liquid sample-extraction procedure combined with column switching resulted in a analytical method with long-term stability. Presented at Balaton Symposium '01 on High-Performance Separation Methods, Siófok, Hungary, September 2–4, 2001     

Activation energy (Δ<Emphasis Type="Italic">G</Emphasis>*), enthalpy (Δ<Emphasis Type="Italic">H</Emphasis>*), and entropy (Δ<Emphasis Type="Italic">S</Emphasis>*) of some indoles and certain of their binary mixtures

Thermodynamic parameters, like, change of activation energy for dipole orientation (ΔG*), enthalpy (ΔH*), and entropy (ΔS*) of activation in the case of binary-, ternary-, etc. mixtures of polar molecules in pure liquid phase or in dilute solution phase in a non polar solvent helps in drawing certain quantitative conclusions regarding their relaxation behavior as to whether a single component is responsible for observed microwave absorption or a cooperative phenomenon (average) by all the dipoles of the mixture contribute to it. Dielectric relaxation behavior of polar molecules in a non-polar solvent, or mixtures of these substances at different microwave frequencies and over a range of temperatures and concentrations give a method of determining these quantities. Such an experimental investigation on verity of systems is necessary to draw quantitative conclusions regarding the system of the molecules which are not studied so as to examine if the results obtained are in favor or against the general conclusions already arrived at, in other systems. With this in view, systematic dielectric measurements in a range of temperatures are carried out at a single microwave frequency on a single weight fraction in benzene of the four substituted indoles, namely, 5-Bromoindole, 5-Fluoroindole, 2,3-Dimethylindole, 2,5-Dimethylindole and on binary (1:1) mixtures of 2,5-Dimethylindole + 5-Bromoindole and 2,3-Dimethylindole + 5-Fluoroindole in benzene as solvent at different temperatures. The results are presented and discussed.     

Structural analysis of <Emphasis Type="Italic">w</Emphasis>/<Emphasis Type="Italic">o</Emphasis>/<Emphasis Type="Italic">w</Emphasis> multiple emulsions by means of DSC

Summary The properties of the inner and the external aqueous phases, were studied in w/o/w multiple emulsions with light microscopic image analysis and differential scanning calorimetry (DSC). The importance of multiple emulsions lies in the presence of these aqueous phases, making them available for sustained, controlled drug delivery systems. Differentiation of these two aqueous phases, studying the effect of manufacturing technology on droplet structure, quantitative determination of phase volumes and any changes occurring during storage are essential when planning w/o/w emulsions. The present study uses microscopic observations combined with DSC measurements in order to identify the formed structure, at developmental stage in case of different components, preparation methods, and stirring rates. These tools are beneficial during manufacturing as in process controls, or to ensure product quality.     

<Emphasis Type="Italic">N,N′</Emphasis>-Bis(triethoxysilylmethyl)thiocarbamide and Poly[<Emphasis Type="Italic">N,N′</Emphasis>-bis(silsesquioxanylmethyl)thiocarbamide <Emphasis Type="Italic">S,S</Emphasis>-dioxide]

Condensation of (aminomethyl)triethoxysilane with thiocarbamide in the presence of catalytic amounts of ammonium sulfate was used to synthesize N,N-bis(triethoxysilylmethyl)thiocarbamide. The latter was brought into oxidative hydrolytic polycondensation with H₂O₂ to obtain poly[N,N′-bis(silsesquioxanylmethyl)thiocarbamide S, S-dioxide] whose properties were compared with the properties of poly[N,N′-bis(silsesquioxanylpropyl)thiocarbamide S,S-dioxide]. Both polymers in highly acidic media rather strongly absorb Ag(I), while at pH 7 they reduce most absorbed Ag⁺ to the metal. Their reaction with potassium permanganate involves reduction of Mn⁷⁺ to Mn⁴⁺. The first polymer is a less effective sorbent and redox agent than the second.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 7, 2005, pp. 1154–1156.Original Russian Text Copyright © 2005 by Voronkov, Vlasova, Grigor’eva, Pozhidaev, Bol’shakova.     

Novel <Emphasis Type="Italic">S</Emphasis>-containing lactones from monoterpene oxides

A new type of S-containing terpene lactones was produced by the reactions of limonene-1,2-oxide and β-pinene-α-oxide with mercaptoacetic acid. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 220–223, May–June, 2007.     

Synthesis of new <Emphasis Type="Italic">N</Emphasis>-aminoglycosides based on halo-substituted <Emphasis Type="Italic">p</Emphasis>-phenylenediamines and <Emphasis Type="Italic">p</Emphasis>-aminophenols

Condensation of the monosaccharides D-glucose and D-galactose with synthesized halo-substituted p-phenylenediamines and 4-amino-2,6-dibromophenol was studied. It was found that glycosylation occurred only at the 4-amino group that was sterically unhindered by the halogen atom. The position of the aglycon in the glycoside was established by PMR spectroscopy.     

Structure and photochromism of 2-(<Emphasis Type="Italic">N</Emphasis>-acyl-<Emphasis Type="Italic">N</Emphasis>-arylaminomethylene)benzo[<Emphasis Type="Italic">b</Emphasis>]thiophen-3(2<Emphasis Type="Italic">H</Emphasis>)-ones

It was shown by electron absorption spectroscopy and X-ray diffraction analysis that steric strains in photochromic 2-(N-acyl-N-arylaminomethylene) benzo[b]thiophen-3(2H)-one molecules ortho-substituted in the N-phenyl ring increase the quantum yield of the N→O photoinduced rearrangement in accord with an increase in the steric constant of the ortho-substituent.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2151–2155, October, 2004.