- 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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- Gold nanoparticles stabilized on nanocrystalline magnesium oxide as an active catalyst for reduction of nitroarenes in aqueous medium at room temperature
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Gold nanoparticles deposited on nanocrystalline magnesium oxide is a very efficient catalyst for the reduction of nitroarenes in aqueous medium at room temperature. Sodium borohydride is used as the source of hydrogen for the reduction of nitro groups. This catalytic system selectively reduces the nitro group even in the presence of other sensitive functional groups under very mild conditions in good to excellent yields without the requirement of any promoters. The reaction kinetics of reduction of 4-nitrophenol to 4-aminophenol has been studied by UV-visible spectrophotometry, and its apparent rate constant has been determined and compared with those of other supported gold catalysts. The spent heterogeneous catalyst is recovered by simple centrifugation, and reused for multiple cycles.
- Layek, Keya,Kantam, M. Lakshmi,Maheswaran, H.,Shirai, Masayuki,Nishio-Hamane, Daisuke,Sasaki, Takehiko
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p. 3164 - 3174,11
(2020/09/16)
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- CYCLIC AMIDES AND IMIDES HAVING SELECTIVE ANTAGONIST ACTIVITY AT ALPHA-1D ADRENERGIC RECEPTOR
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Compounds (I) R and R1 independently = H or C1-C4 alkyl or together = (CH2)2-6, n=0 or 1, ...... is a single or a double bond, A=CO or CH2, A1 represents a CO or CH2 or CH, each R3 independently = H or C1-C4 alkyl, B is B1 or B2 (B2); Y=N or CH, R2 = halogen, C1-C4 alkyl or CN, R5 = halogen, C1-C4 alkyl, polyfluoroalkyl or NO2, R6 = H or halogen, m is 1 to 3, Z = O, S, NH or NMe) interact selectively with the alpha 1D subtype of the alpha 1 adrenergic receptor. This selectively makes these compounds useful agents in tissues particularly rich in alpha 1D adrenergic receptors, thus useful in reducing contractility of an unstable urinary bladder, in the treatment and prevention of atherosclerosis as they are inhibitors of noradrenaline-mediated cell proliferation in smooth muscles, and in reducing vascular adrenergic tone. The preparation of these compounds, their enantiomers, diastereoisomers, N-oxides and pharmaceutically acceptable salts, and pharmaceutical compositions containing them are also claimed.
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- Polyhalogen-substituted cinnamic acids and cinnamic acid derivatives and a process for the preparation of polyhalogen-substituted cinnamic acids and cinnamic acid derivatives
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Polyhalogenated cinnamic acids and cinnamic acid derivatives are prepared by reacting diazonium salts accessible from polyhalogenated anilines with acrylic acid or acrylic acid derivatives in the presence of a homogeneous, palladium-containing catalyst at about ?5 to about +100° C. Some of the cinnamic acids and cinnamic acid derivatives obtainable in this way are new. Cinnamic acids and cinnamic acid derivatives which can be prepared according to the invention can be used for the preparation of indanones which are precursors for agro- and pharmaceutical chemicals and for substances having liquid-crystalline properties.
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