1073313-97-9Relevant articles and documents
Gold-catalyzed direct arylation
Ball, Liam T.,Lloyd-Jones, Guy C.,Russell, Christopher A.
, p. 1644 - 1648,5 (2012)
Biaryls (two directly connected aromatic rings, Ar1-Ar 2) are common motifs in pharmaceuticals, agrochemicals, and organic materials. Current methods for establishing the Ar1-Ar2 bond are dominated by the cross-coupling of aryl halides (Ar1-X) with aryl metallics (Ar2-M). We report that, in the presence of 1 to 2 mole percent of a gold catalyst and a mild oxidant, a wide range of arenes (Ar1-H) undergo site-selective arylation by arylsilanes (Ar 2-SiMe3) to generate biaryls (Ar1-Ar 2), with little or no homocoupling (Ar1-Ar 1/Ar2-Ar2). Catalysis proceeds at room temperature and tolerates a broad range of functional groups, including those incompatible with cross-coupling. These features expedite biaryl preparation, as demonstrated by synthesis of the nonsteroidal anti-inflammatory diflunisal.
Gold-catalyzed oxidative coupling of arylsilanes and arenes: Origin of selectivity and improved precatalyst
Ball, Liam T.,Lloyd-Jones, Guy C.,Russell, Christopher A.
supporting information, p. 254 - 264 (2014/01/23)
The mechanism of gold-catalyzed coupling of arenes with aryltrimethylsilanes has been investigated, employing an improved precatalyst (thtAuBr3) to facilitate kinetic analysis. In combination with linear free-energy relationships, kinetic isotope effects, and stoichiometric experiments, the data support a mechanism involving an Au(I)/Au(III) redox cycle in which sequential electrophilic aromatic substitution of the arylsilane and the arene by Au(III) precedes product-forming reductive elimination and subsequent cycle-closing reoxidation of the metal. Despite the fundamental mechanistic similarities between the two auration events, high selectivity is observed for heterocoupling (C-Si then C-H auration) over homocoupling of either the arylsilane or the arene (C-Si then C-Si, or C-H then C-H auration); this chemoselectivity originates from differences in the product-determining elementary steps of each electrophilic substitution. The turnover-limiting step of the reaction involves associative substitution en route to an arene π-complex. The ramifications of this insight for implementation of the methodology are discussed.
THERAPEUTIC PRO-ANTIBIOTIC AGENTS AND METHODS OF USE THEREOF
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Page/Page column 21-22, (2008/12/08)
The present invention provides for therapies characterized in part by co-administration or combination of antibiotic agents with medicinal compositions comprising as the pro-antibiotic active ingredient either a compound represented by a formula [I] or a
