- Catalyst-Controlled Regioselective Chlorination of Phenols and Anilines through a Lewis Basic Selenoether Catalyst
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We report a highly efficient ortho-selective electrophilic chlorination of phenols utilizing a Lewis basic selenoether catalyst. The selenoether catalyst resulted in comparable selectivities to our previously reported bis-thiourea ortho-selective catalyst, with a catalyst loading as low as 1%. The new catalytic system also allowed us to extend this chemistry to obtain excellent ortho-selectivities for unprotected anilines. The selectivities of this reaction are up to >20:1 ortho/para, while the innate selectivities for phenols and anilines are approximately 1:4 ortho/para. A series of preliminary studies revealed that the substrates require a hydrogen-bonding moiety for selectivity.
- Dinh, Andrew N.,Maddox, Sean M.,Vaidya, Sagar D.,Saputra, Mirza A.,Nalbandian, Christopher J.,Gustafson, Jeffrey L.
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p. 13895 - 13905
(2020/11/03)
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- Ammonium Salt-Catalyzed Highly Practical Ortho-Selective Monohalogenation and Phenylselenation of Phenols: Scope and Applications
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An ortho-selective ammonium chloride salt-catalyzed direct C-H monohalogenation of phenols and 1,1′-bi-2-naphthol (BINOL) with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) as the chlorinating agent has been developed. The catalyst loading was low (down to 0.01 mol %) and the reaction conditions were very mild. A wide range of substrates including BINOLs were compatible with this catalytic protocol. Chlorinated BINOLs are useful synthons for the synthesis of a wide range of unsymmetrical 3-aryl BINOLs that are not easily accessible. In addition, the same catalytic system can facilitate the ortho-selective selenylation of phenols.
- Xiong, Xiaodong,Yeung, Ying-Yeung
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p. 4033 - 4043
(2018/05/22)
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- The Catalyst-Controlled Regiodivergent Chlorination of Phenols
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Different catalysts are demonstrated to overcome or augment a substrate's innate regioselectivity. Nagasawa's bis-thiourea catalyst was found to overcome the innate para-selectivity of electrophilic phenol chlorination, yielding ortho-chlorinated phenols that are not readily obtainable via canonical electrophilic chlorinations. Conversely, a phosphine sulfide derived from 2,2′-Bis(diphenylphosphino)-1,1′-binaphthyl (BINAP) was found to enhance the innate para-preference of phenol chlorination.
- Maddox, Sean M.,Dinh, Andrew N.,Armenta, Felipe,Um, Joann,Gustafson, Jeffrey L.
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supporting information
p. 5476 - 5479
(2016/11/17)
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- EQUILIBRATIVE NUCLEOSIDE TRANSPORTER ENT1 INHIBITORS
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The present invention is related to novel compounds of formula (I) having equilibrative nucleoside transporter ENTl inhibiting properties, pharmaceutical compositions comprising these compounds, chemical processes for preparing these compounds and their use in the treatment of diseases linked to the inhibition of ENTl receptors in animals, in particular humans.
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Page/Page column 40
(2009/06/27)
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- Copper(I)-Induced Bromo-Hydrogen Exchange of 2,3-Dibromoanilines
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The copper(I)-induced bromine-hydrogen exchange reaction of 2,3-dibromoaniline and 5-substituted 2,3-dibromoanilines in the 2-position has been kinetically studied in water-acetic acid-hydrochloric acid medium at 90 deg C.The dehalogenation reaction is of second order, first order in both substrate and Cu+, and may be interpreted as a reductive substitution, composed of two one-electron steps.The 2,3-dibromophenol was only qualitatively investigated, but gave similar results.
- Liedholm, Brita
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p. 877 - 884
(2007/10/02)
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