The Experts below are selected from a list of 67440 Experts worldwide ranked by ideXlab platform
Samir Zard - One of the best experts on this subject based on the ideXlab platform.
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Unusual approach to branched 3-alkynylamides and to 1,5-dihydropyrrol-2- ones
Organic Letters, 2010Co-Authors: Igor Dias-jurberg, Fabien Gagosz, Samir ZardAbstract:[Chemical Equation presented] Rare carboxamide branched alkynes such as 11a can be readily obtained by reaction of the electrophilic 4-alkylidene isoxazolinones with isocycanides followed by nitrosative cleavage of the heterocyclic ring. N-lodosuccinimide induced ring closure in the presence of a nucleophile results in the formation of new iodopyrrolinones such as 16c. © 2010 American Chemical Society.
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Radical allylation with a-branched allyl sulfones
Angewandte Chemie International Edition, 2008Co-Authors: Nicolas Charrier, Samir ZardAbstract:(Chemical Equation Presented) Branching out with sulfones: The use of allyl isopropyl sulfones solves the problem of premature isomerization and allows the radical addition of xanthates to a-branched allyl sulfones (see scheme; DCE=1,2-dichloroethane, TMS=trimethylsilyl). Highly functionalized structures can thus be rapidly assembled under mild reaction conditions by using cheap and readily available substrates and reagents. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.
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Substituted allyl diphenylphosphine oxides as radical allylating agents
Angewandte Chemie International Edition, 2006Co-Authors: Gilles Ouvry, Béatrice Quiclet-sire, Samir ZardAbstract:(Chemical Equation Presented) Radically useful: The radical addition of dithiocarbonates to branched allyl diphenylphosphine oxides can be followed by elimination of a diphenylphosphinoyl radical, thereby giving rise to allylated products (see scheme; Phth = phthalimido). Highly functionalized structures can thus be rapidly assembled under mild conditions and from cheap and readily available substrates and reagents. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA.
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Cyano(ethoxycarbonothioylthio)methyl benzoate: A novel one-carbon radical equivalent
Organic Letters, 2006Co-Authors: Sharanjee Bagal, Michiel De Greef, Samir ZardAbstract:(Chemical Equation Presented) Cyano(ethoxycarbonothioylthio)methyl benzoate 3 has been prepared and shown to be an excellent one-carbon radical equivalent that can be applied for the introduction of an acyl unit via xanthate transfer radical addition to olefins. The corresponding adducts can be further elaborated. A rare 1,5-nitrile translocation was also observed during the study. © 2006 American Chemical Society.
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Radical additions of xanthates to vinyl epoxides and related derivatives: A powerful tool for the modular creation of quaternary centers
Angewandte Chemie International Edition, 2006Co-Authors: Nicolas Charrier, David Gravestock, Samir ZardAbstract:(Chemical Equation Presented) An open relationship: The triethylborane/O2-mediated addition of xanthates to vinyl epoxides and derivatives represents an efficient process to form carbon-carbon bonds. Complex structures can be rapidly assembled in a modular, convergent manner, under mild conditions, using readily available reagents (see scheme, Bn = benzyl). The formation of quaternary centers proved especially facile. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA.
Tetsurou Kasai - One of the best experts on this subject based on the ideXlab platform.
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Chemical shrinkage and autogenous shrinkage of hydrating cement paste
Cement and Concrete Research, 1995Co-Authors: Ei-ichi Tazawa, Shingo Miyazawa, Tetsurou KasaiAbstract:Abstract It is well known that the absolute volume of cement plus water decrease with progressive hydration. In this study, Chemical shrinkage of cement was calculated from Chemical Equation of hydration, it was compared with observed one. Definition of Chemical shrinkage and autogenous shrinkage was made and relationship between them was clearly described.
Nicolas Charrier - One of the best experts on this subject based on the ideXlab platform.
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Radical allylation with a-branched allyl sulfones
Angewandte Chemie International Edition, 2008Co-Authors: Nicolas Charrier, Samir ZardAbstract:(Chemical Equation Presented) Branching out with sulfones: The use of allyl isopropyl sulfones solves the problem of premature isomerization and allows the radical addition of xanthates to a-branched allyl sulfones (see scheme; DCE=1,2-dichloroethane, TMS=trimethylsilyl). Highly functionalized structures can thus be rapidly assembled under mild reaction conditions by using cheap and readily available substrates and reagents. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.
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Radical additions of xanthates to vinyl epoxides and related derivatives: A powerful tool for the modular creation of quaternary centers
Angewandte Chemie International Edition, 2006Co-Authors: Nicolas Charrier, David Gravestock, Samir ZardAbstract:(Chemical Equation Presented) An open relationship: The triethylborane/O2-mediated addition of xanthates to vinyl epoxides and derivatives represents an efficient process to form carbon-carbon bonds. Complex structures can be rapidly assembled in a modular, convergent manner, under mild conditions, using readily available reagents (see scheme, Bn = benzyl). The formation of quaternary centers proved especially facile. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA.
Vikram R. Jadhav - One of the best experts on this subject based on the ideXlab platform.
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A Procedure Employing for Redox Titration: Balancing the Redox Chemical Equation in Acidic or Basic Medium
International Journal of Research, 2020Co-Authors: Sneha G. Nair, Tushar S. More, Vikram R. JadhavAbstract:Graduate and post graduate students find much more difficulty during the concept of the balancing redox Chemical Equation in acidic or basic medium. Teachers are well aware of the importance of the balancing redox Chemical Equation in both medium and also teaching difficulty associated with it. In an attempt to improving the understanding of the balancing the redox Chemical Equation with reduced difficulty, a mathematical approach that provides easier understanding has been developed and successfully employed in graduate and post graduate students. In this study, relation between an oxidising agent (Oxidant) and reducing agent (reductant) can be employed in redox Chemical titration, using potassium permanganate (KMnO4) is an oxidant itself act as the indicator, during the titration of Cr (III) ion, as reducing agent with KMnO4, the second titration oxidation of H2O2, is used as a reducing agent against the KMnO4. Data obtained from titrations will lead to balancing each redox Chemical Equation in an acidic or basic medium.
Karl Gademann - One of the best experts on this subject based on the ideXlab platform.
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A Synthetic Entry into the Taiwaniaquinoids Based on a Biogenetic Hypothesis : Total Synthesis of (-)-Taiwaniaquinone H
Chemistry - A European Journal, 2010Co-Authors: Chandan K. Jana, Rosario Scopelliti, Karl GademannAbstract:(Chemical Equation Presented) Less carbon: Following a biogenetic proposal, the unusual 6-5-6 carbon skeleton of C19 taiwaniaquinoids was obtained by an intramolecular benzilic acid rearrangement from a C20 precur-sor. A protecting-group-free total synthesis then allowed for the preparation of (-)-taiwaniaquinone H (see scheme). © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.