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Organic Medium (organic + medium)

Distribution by Scientific Domains
Polymers and Materials Science50%
Chemistry50%

Selected Abstracts

Promiscuous Zinc-Dependent Acylase-Mediated One-Pot Synthesis of Monosaccharide-Containing Pyrimidine Derivatives in Organic Medium

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009
Qi Wu
Abstract A facile one-pot synthesis route to monosaccharide-containing pyrimidine derivatives was developed by combining the two types of catalytic activities of one enzyme in an organic medium, i.e., the Michael addition/acylation activities of zinc-dependent D -aminoacylase (DA) from Escherichia coli. First, the stepwise approach was investigated. DA showed higher activity towards the Michael addition than acylation in this reaction system. The enzymatic Michael additions of pyrimidines to vinyl acrylate proceeded very rapidly and the initial reaction rates for the Michael addition of pyrimidines to vinyl acrylate were 7.2,16.5,mM,min,1. The catalytic specificity of aminoacylases toward Michael addition was demonstrated by the combination of different control experiments. Then, the two steps could be performed in one pot and a single aminoacylase catalyzed one-pot biotransformation was constructed. Using this strategy, a series of saccharide-pyrimidine complexes with potentially biological and pharmacological applications was prepared efficiently. This high Michael addition activity of zinc-dependent aminoacylases and the novel single aminoacylase-catalyzed one-pot synthesis combining two catalytic activities in vitro is of practical significance in expanding the application of enzymes and in the evolution of new biocatalysts. [source]

ChemInform Abstract: Bakers, Yeast Catalyzed Synthesis of Benzothiazoles in an Organic Medium.

CHEMINFORM, Issue 26 2009
Umesh R. Pratap
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Promiscuous Zinc-Dependent Acylase-Mediated One-Pot Synthesis of Monosaccharide-Containing Pyrimidine Derivatives in Organic Medium

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009
Qi Wu
Abstract A facile one-pot synthesis route to monosaccharide-containing pyrimidine derivatives was developed by combining the two types of catalytic activities of one enzyme in an organic medium, i.e., the Michael addition/acylation activities of zinc-dependent D -aminoacylase (DA) from Escherichia coli. First, the stepwise approach was investigated. DA showed higher activity towards the Michael addition than acylation in this reaction system. The enzymatic Michael additions of pyrimidines to vinyl acrylate proceeded very rapidly and the initial reaction rates for the Michael addition of pyrimidines to vinyl acrylate were 7.2,16.5,mM,min,1. The catalytic specificity of aminoacylases toward Michael addition was demonstrated by the combination of different control experiments. Then, the two steps could be performed in one pot and a single aminoacylase catalyzed one-pot biotransformation was constructed. Using this strategy, a series of saccharide-pyrimidine complexes with potentially biological and pharmacological applications was prepared efficiently. This high Michael addition activity of zinc-dependent aminoacylases and the novel single aminoacylase-catalyzed one-pot synthesis combining two catalytic activities in vitro is of practical significance in expanding the application of enzymes and in the evolution of new biocatalysts. [source]

Binding of several heavy metal ions by polyaspartyl polymers and their application to some Chinese herbal medicines

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2007
Bo Sun
Abstract Water-insoluble polyaspartyl polymers were synthesized by using water as medium instead of organic medium. Taking Ca2+ as a reference, the binding of several heavy-metal ions, including Pb2+, Cd2+, Hg2+, Cr3+, Cu2+, and Mn2+, by polyaspartyl polymers was studied. The experimental results revealed that polyaspartate is an excellent binding agent for the investigated heavy-metal ions. These cation ions were bound to polyaspartate polymer by the same mechanism as Pb2+, which can be explained by ion exchange model. Since polyaspartate has a protein-resembling structure that is sensitive to trace heavy metal, it was used to remove some trace heavy-metal elements in Chinese herbal medicines. It was found that polyaspartate material was an effective agent for the removal of Pb2+, Cd2+, and Hg2+ ions from glycyrrhizin, angelica, and gynostemma pentaphyllum. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source]

Polypyrrole/polyaniline conductive films obtained electrochemically on polycarbonate-coated platinum electrodes

POLYMER INTERNATIONAL, Issue 12 2002
Meral Karak
Abstract In this study, two-component free-standing films were obtained by coating a polycarbonate (PC)-coated Pt electrode first with polypyrrole (PPy) in an organic medium and then polyaniline (PAn) in an aqueous medium using an electrochemical technique. The amount of PPy and PAn contained in the films was controlled by varying the electrolysis time. The PC/PPy/PAn films were characterized by cyclic voltammetry, conductivity, FTIR and UV,visible spectrophotometry, and thermogravimetric analysis. The resistance change of the films was determined in the temperature range of ,15 to 120,°C and their temperature sensor properties were investigated. © 2002 Society of Chemical Industry [source]

Telomerization of acrylic acid with mercaptans: Part 2.

POLYMER INTERNATIONAL, Issue 4 2001
Kinetics of the synthesis of star-shaped macromolecules of acrylic acid
Abstract The telomerization of acrylic acid with a polyfunctional transfer agent initiated by 2,2,-azobisisobutyronitrile, was first investigated in an organic medium (THF) at 65,°C. Transfer constants (CT) for three mercaptans, ethylene glycol bisthioglycolate, trimethylolpropane tris(2-mercaptoacetate) and pentaerythritol tetrakis(3-mercaptopropionate) of about 6.1, 6.3 and 7.3, respectively, were determined. From these results, it followed that a well-defined star poly(acrylic acid) could not be synthesized via telomerization of acrylic acid in THF. Nevertheless, the same study was performed with the tetrafunctional transfer agent in water/THF mixtures. This work emphasized that the nature of the solvent plays an important role in determining the transfer constant. Thus, the value of CT for the tetrafunctional transfer agent decreased from 7.3 in THF to 1, the ,ideal' case for telomerization (CT,,,1), for the mixture of solvents water/THF (80%, 20%, v/v). With this route, it seems that acrylic acid star-shaped macromolecules could be synthesized via telomerization. © 2001 Society of Chemical Industry [source]