- N-phenylphthalimide-type cyclooxygenase (COX) inhibitors derived from thalidomide: Substituent effects on subtype selectivity
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Several N-substituted phenylphthalimide and phenylhomophthalimide derivatives with cyclooxygenase (COX)-inhibitory activity were prepared during structural development studies based on thalidomide as a lead compound. Substituent effects on the subtype selectivity were investigated.
- Sano, Hiroko,Noguchi, Tomomi,Tanatani, Aya,Miyachi, Hiroyuki,Hashimoto, Yuichi
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- Asymmetric Synthesis of Indoline from Achiral Phthalimide Involving Crystallization-Induced Deracemization
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Asymmetric synthesis was performed by combining the photochemical reaction of an achiral substrate followed by crystallization-induced deracemization. The results indicated that a fused indoline produced by photochemical intramolecular δ-hydrogen abstraction and cyclization of N-(5-chloro-2-methylphenyl)phthalimide crystallized as a racemic conglomerate. Since this substrate has an aminal skeleton, racemization involving a ring-opening and ring-closing equilibrium process occurred under suitable conditions. Efficient racemization was observed in acetone containing a catalytic base, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Crystallization-induced dynamic deracemization by Viedma ripening from racemic indoline was performed with an excellent enantioselectivity of 99 % ee. Furthermore, one-pot asymmetric synthesis of the indoline was achieved by the photochemical reaction of achiral phthalimide followed by continuous attrition-enhanced deracemization converging to 99 % ee of enantiomeric crystals. This is the first example of asymmetric expression and amplification by photochemical hydrogen abstraction and crystallization-induced dynamic deracemization.
- Nakamura, Takumi,Ban, Kazuma,Yoshida, Yasushi,Mino, Takashi,Kasashima, Yoshio,Sakamoto, Masami
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supporting information
p. 16338 - 16341
(2021/10/12)
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- Visible-Light-Induced Metal-/Photocatalyst-Free C-H Bond Imidation of Arenes
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In this study, a visible-light-induced intermolecular C-H bond imidation of arenes was achieved at ambient condition. By using simple phthalimide with (diacetoxyiodo)benzene and molecular iodine, direct metal-/photocatalyst-free C-N bond formation was achieved. The imidation protocol was designed by using time-dependent density functional theory calculations and experimentally demonstrated for 28 substrates with as high as 96% yield. Mechanistic studies indicated that radical-mediated aromatic substitution occurred via photolysis of N-iodophthalimide under visible-light irradiation.
- Kuribara, Takahito,Nakajima, Masaya,Nemoto, Tetsuhiro
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supporting information
p. 2235 - 2239
(2020/03/13)
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- Regioselective gold-catalyzed oxidative C-N bond formation
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A novel protocol for the regioselective intermolecular amination of various arenes has been developed. By using an I(III) oxidant in the presence of a Au(I) catalyst, a direct and novel route for regioselectively accessing a variety of substituted aniline moieties has been achieved with yields as high as 90%. Mechanistic insight suggests that regioselectivity can be predicted based on electrophilic aromatic metalation patterns.
- Marchetti, Louis,Kantak, Abhishek,Davis, Riley,Deboef, Brenton
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supporting information
p. 358 - 361
(2015/01/30)
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- Nitrogen-centered radical-mediated C-H imidation of arenes and heteroarenes via visible light induced photocatalysis
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The C-H imidation of arenes and heteroarenes has been achieved via visible light induced photocatalysis. In the presence of an iridium(iii) photoredox catalyst, the reaction of aromatic substrates with N-chlorophthalimide furnishes the N-aryl products at room temperature through a nitrogen-centered radical mediated aromatic substitution.
- Kim, Hyejin,Kim, Taehoon,Lee, Dong Gil,Roh, Sang Weon,Lee, Chulbom
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supporting information
p. 9273 - 9276
(2014/08/05)
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- Sterically controlled, palladium-catalyzed intermolecular amination of arenes
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We report the Pd-catalyzed amination of arenes to form N-aryl phthalimides with regioselectivity controlled predominantly by steric effects. Mono-, di-, and trisubstituted arenes lacking a directing group undergo amination reactions with moderate to high yields and high regioselectivities from sequential addition of PhI(OAc)2 as an oxidant in the presence of Pd(OAc) 2 as catalyst. This sterically derived selectivity contrasts that for analogous arene acetoxylation.
- Shrestha, Ruja,Mukherjee, Paramita,Tan, Yichen,Litman, Zachary C.,Hartwig, John F.
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supporting information
p. 8480 - 8483
(2013/07/19)
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- Intermolecular oxidative C-N bond formation under metal-free conditions: Control of chemoselectivity between aryl sp2 and benzylic sp 3 C-H bond imidation
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A new synthetic approach toward intermolecular oxidative C-N bond formation of arenes has been developed under transition-metal-free conditions. Complete control of chemoselectivity between aryl sp2 and benzylic sp 3 C-H bond imidation was achieved by the choice of nitrogen sources, representatively being phthalimide and dibenzenesulfonimide, respectively.
- Kim, Hyun Jin,Kim, Jiyu,Cho, Seung Hwan,Chang, Sukbok
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supporting information; experimental part
p. 16382 - 16385
(2011/12/13)
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- Metal-free intermolecular oxidative C-N bond formation via tandem C-H and N-H bond functionalization
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The development of a novel intermolecular oxidative amination reaction, a synthetic transformation that involves the simultaneous functionalization of both a N-H and C-H bond, is described. The process, which is mediated by an I(III) oxidant and contains no metal catalysts, provides a rapid and green method for synthesizing protected anilines from simple arenes and phthalimide. Mechanistic investigations indicate that the reaction proceeds via nucleophilic attack of the phthalimide on an aromatic radical cation, as opposed to the electrophilic aromatic amination that has been reported for other I(III) amination reactions. The application of this new reaction to the synthesis of a variety of substituted aniline derivatives is demonstrated.
- Kantak, Abhishek A.,Potavathri, Shathaverdhan,Barham, Rose A.,Romano, Kaitlyn M.,Deboef, Brenton
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supporting information; experimental part
p. 19960 - 19965
(2012/01/13)
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