93298-19-2Relevant academic research and scientific papers
METHOD FOR ESTABLISHING CC BONDS BETWEEN ELECTROPHILIC SUBSTRATES AND ? - NUCLEOPHILES IN NEUTRAL TO ALKALINE AQUEOUS OR ALCOHOLIC SOLVENTS WITHOUT USING A LEWIS OR BRONSTED ACID
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Page/Page column 12-13, (2008/06/13)
The invention relates to a method for establishing carbon-carbon bonds by reacting electropohilic substrates that have a solvolysis rate kEtOH (25°C) > 10-6 s-1 and ? compounds. The method is characterized by generating the intermediary carbocations in neutral to alkaline aqueous or alcoholic solvents or solvent mixtures without using a Lewis or Br?nsted acid.
Nucleophilic reactivities of silyl ketene acetals and silyl enol ethers containing (C6F5)3SiO and (C6H 5)3SiO groups
Dilman, Alexander D.,Mayr, Herbert
, p. 1760 - 1764 (2007/10/03)
The kinetics of the reactions of tris(pentafluorophenyl)silyl and triphenylsilyl ketene acetals and enol ethers with benzhydrylium cations have been measured photometrically. The second-order rate constants (log k 2) have been used to determine the nucleophilicity parameters of these π systems, which provide a quantitative comparison of their reactivities with those of other types of nucleophiles. A change from, trimethylsilyloxy to triphenylsilyloxy reduces reactivity by only a factor of ten, while replacement of triphenylsilyloxy with tris(pentafluorophenyl)silyloxy decreases the nucleophilicity of the enolate C=C double bond by three to four orders of magnitude. The cation-stabilizing ability of the tris(pentafluorophenyl)silyloxy group is thus similar to that of a methyl group. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
Aminoalcohol derivatives and their use as beta 3 adrenergic agonists
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, (2008/06/13)
This invention relates to new aminoalcohol derivatives or salts thereof represented by the following formula [I]: wherein each symbol is as defined in the specification or salts thereof which have gut selective sympathomimetic, anti-ulcerous, anti-pancreatitis, lipolytic, anti-urinary incontinence and anti-pollakiuria activities, to processes for the preparation thereof, to a pharmaceutical composition comprising the same and to a method for the prevention and/or treatment diseases indicated in the specification to a human being or an animal.
Novel Pd(II)- and Pt(II)-catalyzed regio- and stereoselective trans-hydroarylation of alkynes by simple arenes
Jia, Chengguo,Lu, Wenjun,Oyamada, Juzo,Kitamura, Tsugio,Matsuda, Kenji,Irie, Masahiro,Fujiwara, Yuzo
, p. 7252 - 7263 (2007/10/03)
Efficient trans-hydroarylation of alkynes by simple arenes has been realized regio- and stereoselectively at room temperature in the presence of Pd(II) or Pt(II) catalysts and a mixed solvent containing trifluoroacetic acid (TFA). Various arenes undergo trans-hydroarylation selectively across terminal and internal C - C triple bonds - including those conjugated to CHO, COMe, CO2H, and CO2Et groups, affording kinetically controlled cis-arylalkenes predominantly in most cases, especially, in good yields for electron-rich arenes and activated alkynes. The formation of arene/alkyne 1/2 or 2/1 adducts as side products is dependent on the arenes' and alkynes' substituents, which can be suppressed in some cases by changing the catalyst, catalyst concentration, and reaction time. The Pt(II) system, PtCl2/2AgOAc/TFA, shows lower catalytic activity than Pd(OAc)2/TFA, but higher selectivity, giving higher yields of adducts at the same conversion. On the basis of several isotope experiments and control reactions, a possible mechanism involving electrophilic metalation of aromatic C - H bonds by in-situ-generated cationic Pd(II) and Pt(II) species leading to intermolecular trans-arylpalladation to alkyes has been discussed.
