- A protocol to generate phthaloyl peroxide in flow for the hydroxylation of arenes
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A flow protocol for the generation of phthaloyl peroxide has been developed. This process directly yields phthaloyl peroxide in high purity (>95%) and can be used to bypass the need to isolate and recrystallize phthaloyl peroxide, improving upon earlier batch procedures. The flow protocol for the formation of phthaloyl peroxide can be combined with arene hydroxylation reactions and provides a method for the consumption of peroxide as it is generated to minimize the accumulation of large quantities of peroxide.
- Eliasen, Anders M.,Thedford, Randal P.,Claussen, Karin R.,Yuan, Changxia,Siegel, Dionicio
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supporting information
p. 3628 - 3631
(2014/08/05)
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- CYCLIC PEROXIDE OXIDATION OF AROMATIC COMPOUND PRODUCTION AND USE THEREOF
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The present invention provides a method for converting an aromatic hydrocarbon to a phenol by providing an aromatic hydrocarbon comprising one or more aromatic C-H bonds and one or more activated C-H bonds in a solvent; adding a phthaloyl peroxide to the solvent; converting the phthaloyl peroxide to a di-radical; contacting the di-radical with the one or more aromatic C-H bonds; oxidizing selectively one of the one or more aromatic C-H bonds in preference to the one or more activated C-H bonds; adding a hydroxyl group to the one of the one or more aromatic C-H bonds to form one or more phenols; and purifying the one or more phenols.
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Page/Page column 9; 10
(2014/10/15)
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- METHODS FOR THE PREPARATION OF SUBSTITUTED ACETOPHENONES
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The present application discloses novel methods for the preparation of pyrid-4-yl substituted acetophenones, in particular 2-{6-[2-(3,5-dichloro-pyridin-4-yl)-acetyl]-2,3-dimethoxy-phenoxy}-N-propyl-acetamide. The application also discloses novel stable c
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Page/Page column 33
(2014/07/08)
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- Metal-free oxidation of aromatic carbon-hydrogen bonds through a reverse-rebound mechanism
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Methods for carbon-hydrogen (C-H) bond oxidation have a fundamental role in synthetic organic chemistry, providing functionality that is required in the final target molecule or facilitating subsequent chemical transformations. Several approaches to oxidizing aliphatic C-H bonds have been described, drastically simplifying the synthesis of complex molecules. However, the selective oxidation of aromatic C-H bonds under mild conditions, especially in the context of substituted arenes with diverse functional groups, remains a challenge. The direct hydroxylation of arenes was initially achieved through the use of strong Bronsted or Lewis acids to mediate electrophilic aromatic substitution reactions with super-stoichiometric equivalents of oxidants, significantly limiting the scope of the reaction. Because the products of these reactions are more reactive than the starting materials, over-oxidation is frequently a competitive process. Transition-metal-catalysed C-H oxidation of arenes with or without directing groups has been developed, improving on the acid-mediated process; however, precious metals are required. Here we demonstrate that phthaloyl peroxide functions as a selective oxidant for the transformation of arenes to phenols under mild conditions. Although the reaction proceeds through a radical mechanism, aromatic C-H bonds are selectively oxidized in preference to activated-H bonds. Notably, a wide array of functional groups are compatible with this reaction, and this method is therefore well suited for late-stage transformations of advanced synthetic intermediates. Quantum mechanical calculations indicate that this transformation proceeds through a novel addition-abstraction mechanism, a kind of 'reverse-rebound' mechanism as distinct from the common oxygen-rebound mechanism observed for metal-oxo oxidants. These calculations also identify the origins of the experimentally observed aryl selectivity.
- Yuan, Changxia,Liang, Yong,Hernandez, Taylor,Berriochoa, Adrian,Houk, Kendall N.,Siegel, Dionicio
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p. 192 - 196
(2013/08/23)
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- Sequential removal of photolabile protecting groups for carbonyls with controlled wavelength
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(Chemical Equation Presented) A group of robust and easy-to-make photolabile protecting groups (PPGs) for carbonyl compounds has been developed. Sequential removal of different PPGs is achieved via control of irradiation wavelength.
- Wang, Pengfei,Wang, Yun,Hu, Huayou,Spencer, Cierra,Liang, Xing,Pan, Lurong
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p. 6152 - 6157
(2008/12/22)
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- SUBSTITUTED ACETOPHENONES USEFUL AS PDE4 INHIBITORS
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The present invention relates to a compound according to formula: (I); wherein X1, X2, X3, X4 and X5 independently of each other represent -CH- or N; or X3, X4 and X5
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Page/Page column 92
(2008/12/06)
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- Quinolines and quinazolines useful in therapy
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Compounds of formula I, wherein R1 represents C1-4 alkoxy optionally substituted by one or more fluorine atoms; R2 and R3 independently represent H or C1-6 alkoxy (which is optionally substituted); R4 represents a 4-, 5-, 6- or 7-membered heterocyclic rin
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