Home  About us  Contact
 

Group Transformation (group + transformation)

Distribution by Scientific Domains
Chemistry71%
Distribution within Chemistry
Organic Chemistry59%
Chemical Engineering39%

Kinds of Group Transformation

  • functional group transformation
    		•

    Selected Abstracts

    Functional Group Transformation of Perfluoroadamantane Derivatives.

    CHEMINFORM, Issue 49 2006
    Koichi Murata
    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, please click on HTML or PDF. [source]

    Realization of the Synthesis of ,,,-Disubstituted Carbamylacetates and Cyanoacetates by Either Enzymatic or Chemical Functional Group Transformation, Depending upon the Substrate Specificity of Rhodococcus Amidase.

    CHEMINFORM, Issue 9 2005
    Masahiro Yokoyama
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]

    Biotransformation of benzaldehyde to L -phenylacetylcarbinol (L -PAC) by Torulaspora delbrueckii and conversion to ephedrine by microwave radiation

    JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2002
    Vilas B Shukla
    Abstract In a 5,dm3 stirred tank reactor, bioconversion of 30,g benzaldehyde by cells of Torulaspora delbrueckii yielded 22.9,g of pure L -phenylacetylcarbinol (L -PAC). Facile functional group transformation of 4.5,g of L -PAC to 2-(methylimino)-1-phenyl-1-propanol by exposure to microwave irradiation for 9,min resulted in 2.48,g of product. Conversion of 4.8,g of 2-(methylimino)-1-phenyl-1-propanol to 3.11,g of ephedrine was achieved by exposure to microwaves in a reaction time of 10,min. The identity of all the products was confirmed by 1H NMR and FT-IR analysis. © 2002 Society of Chemical Industry [source]

    Theoretical study of wetting behavior of nanoparticles at fluid interfaces

    AICHE JOURNAL, Issue 3 2009
    Jianguo Mi
    Abstract In this work, a theoretical model was developed to describe the wetting behavior of nanoparticles at liquid-vapor interface by the integration of the renormalization group transformation, the cell theory, and the modified fundamental measurement theory with the first-order mean spherical approximation method. The results show that the new model can be used to investigate the global behavior and surface tensions of nanoparticle/fluid systems. Particularly, the nanoparticle's wetting behavior inside critical region was discussed systematically. More important, this work proposed a methodology for calculating line tension and contact angle, showing that line tension has considerable influence on wetting properties for small nanoparticles, whereas it is negligible for large nanoparticles. Therefore, this work provides a general method for studying the wetting behavior of nanoparticles that may find wide applications in the field of chemical engineering. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

    An efficient synthetic route to well-defined theta-shaped copolymers

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 10 2009
    Gang-Yin Shi
    Abstract A series of well-defined ,-shaped copolymers composed of polystyrene (PS) and poly(,-caprolactone) (PCL) with controlled molecular weight and narrow molecular weight distribution have been successfully synthesized without any purification procedure by the combination of atom transfer radical polymerization (ATRP), ring-opening polymerization (ROP), and the "click" chemistry. The synthetic process involves two steps: (1) synthesis of AB2 miktoarm star copolymers, which contain one PCL chain terminated with two acetylene groups and two PS chains with two azido groups at their one end, (,,,,-diacetylene-PCL) (,-azido-PS)2, by ROP, ATRP, and the terminal group transformation; (2) intramolecular cyclization of AB2 miktoarm star copolymers to produce well-defined pure ,-shaped copolymers using "click" chemistry under high dilution. The 1H NMR, FTIR, and gel permeation chromatography techniques were applied to characterize the chemical structures of the resultant intermediates and the target polymers. Their thermal behavior was investigated by DSC. The mobility decrease of PCL chain across PS ring in the theta-shaped copolymers restricts the crystallization ability of PCL segment. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2620,2630, 2009 [source]

    Stereoselective Construction of a Highly Functionalized Taxoid ABC-Ring System: the C2,C9 Oxa-Bridge Approach

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 19 2005
    Sylvain Hamon
    Abstract The goal of this investigation is to assemble the 20-carbon unit 1 of the taxoid diterpene skeleton with a high level of stereocontrol by means of a three-reaction sequence developed in this laboratory. The strategy involves seven C,C bond-forming operations together with eighteen functional group transformations, circumventing the stereoselectivity issue altogether. Furthermore, there is no isomer formation and hence no need for chromatographic separation. A temporary oxa-bridge (C2/C9) was used as a problem-solving approach. The key step in the planned sequence was based on achieving the last C,C bonding between C11 and C12, following a successful C11 functionalization. X-ray analyses of 8b, 17, 18, 19, 20, and 21, together with extensive use of 800 MHz 1H (200 MHz 13C) NMR spectra, support the suggested structures. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

    Optimised Dirac operators on the lattice: construction, properties and applications

    FORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 2 2008
    2Article first published online: 29 NOV 200, W. Bietenholz
    Abstract We review a number of topics related to block variable renormalisation group transformations of quantum fields on the lattice, and to the emerging perfect lattice actions. We first illustrate this procedure by considering scalar fields. Then we proceed to lattice fermions, where we discuss perfect actions for free fields, for the Gross-Neveu model and for a supersymmetric spin model. We also consider the extension to perfect lattice perturbation theory, in particular regarding the axial anomaly and the quark gluon vertex function. Next we deal with properties and applications of truncated perfect fermions, and their chiral correction by means of the overlap formula. This yields a formulation of lattice fermions, which combines exact chiral symmetry with an optimisation of further essential properties. We summarise simulation results for these so-called overlap-hypercube fermions in the two-flavour Schwinger model and in quenched QCD. In the latter framework we establish a link to Chiral Perturbation Theory, both, in the p -regime and in the ,-regime. In particular we present an evaluation of the leading Low Energy Constants of the chiral Lagrangian , the chiral condensate and the pion decay constant , from QCD simulations with extremely light quarks. [source]