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Noritaka Mizuno - One of the best experts on this subject based on the ideXlab platform.
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selective synthesis of primary anilines from nh3 and cyclohexanones by utilizing preferential adsorption of styrene on the pd nanoparticle surface
Angewandte Chemie, 2019Co-Authors: Yu Koizumi, Xiongjie Jin, Kyoko Nozaki, Noritaka Mizuno, Takafumi Yatabe, Ray Miyazaki, Junya Hasegawa, Kazuya YamaguchiAbstract:Dehydrogenative aromatization is one of the attractive alternative methods for directly synthesizing primary anilines from NH3 and cyclohexanones. However, the selective synthesis of primary anilines is quite difficult because the desired primary aniline products and the cyclohexanone substrates readily undergo condensation affording the corresponding imines (i.e., N-cyclohexylidene-anilines), followed by hydrogenation to produce N-cyclohexylanilines as the major products. In this study, primary anilines were selectively synthesized in the presence of supported Pd nanoparticle catalysts (e.g., Pd/HAP, HAP=hydroxyapatite, Ca10 (PO4 )6 (OH)2 ) by utilizing competitive adsorption unique to heterogeneous catalysis; in other words, when styrene was used as a hydrogen acceptor, which preferentially adsorbs on the Pd nanoparticle surface in the presence of N-cyclohexylidene-anilines, various structurally diverse primary anilines were selectively synthesized from readily accessible NH3 and cyclohexanones. The Pd/HAP catalyst was reused several times though its catalytic performance gradually declined.
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selective synthesis of primary anilines from cyclohexanone oximes by the concerted catalysis of a mg al layered double hydroxide supported pd catalyst
Journal of the American Chemical Society, 2017Co-Authors: Xiongjie Jin, Yu Koizumi, Kazuya Yamaguchi, Kyoko Nozaki, Noritaka MizunoAbstract:Although the selective conversion of cyclohexanone oximes to primary anilines would be a good complement to the classical synthetic methods for primary anilines, which utilize arenes as the starting materials, there have been no general and efficient methods for the conversion of cyclohexanone oximes to primary anilines until now. In this study, we have successfully realized the efficient conversion of cyclohexanone oximes to primary anilines by utilizing a Mg-Al layered double hydroxide supported Pd catalyst (Pd(OH)x/LDH) under ligand-, additive-, and hydrogen-acceptor-free conditions. The substrate scope was very broad with respect to both cyclohexanone oximes and cyclohexenone oximes, which gave the corresponding primary anilines in high yields with high selectivities (17 examples, 75% to >99% yields). The reaction could be scaled up (gram-scale) with a reduced amount of the catalyst (0.2 mol %). Furthermore, the one-pot synthesis of primary anilines directly from cyclohexanones and hydroxylamine was also successful (five examples, 66-99% yields). The catalysis was intrinsically heterogeneous, and the catalyst could be reused for the conversion of cyclohexanone oxime to aniline at least five times with keeping its high catalytic performance. Kinetic studies and several control experiments showed that the high activity and selectivity of the present catalyst system were attributed to the concerted catalysis of the basic LDH support and the active Pd species on LDH. The present transformation of cyclohexanone oximes to primary anilines proceeds through a dehydration/dehydrogenation sequence, and herein the plausible reaction mechanism is proposed on the basis of several pieces of experimental evidence.
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Selective Synthesis of Primary Anilines from Cyclohexanone Oximes by the Concerted Catalysis of a Mg–Al Layered Double Hydroxide Supported Pd Catalyst
2017Co-Authors: Xiongjie Jin, Yu Koizumi, Kazuya Yamaguchi, Kyoko Nozaki, Noritaka MizunoAbstract:Although the selective conversion of cyclohexanone oximes to primary anilines would be a good complement to the classical synthetic methods for primary anilines, which utilize arenes as the starting materials, there have been no general and efficient methods for the conversion of cyclohexanone oximes to primary anilines until now. In this study, we have successfully realized the efficient conversion of cyclohexanone oximes to primary anilines by utilizing a Mg–Al layered double hydroxide supported Pd catalyst (Pd(OH)x/LDH) under ligand-, additive-, and hydrogen-acceptor-free conditions. The substrate scope was very broad with respect to both cyclohexanone oximes and cyclohexenone oximes, which gave the corresponding primary anilines in high yields with high selectivities (17 examples, 75% to >99% yields). The reaction could be scaled up (gram-scale) with a reduced amount of the catalyst (0.2 mol %). Furthermore, the one-pot synthesis of primary anilines directly from cyclohexanones and hydroxylamine was also successful (five examples, 66–99% yields). The catalysis was intrinsically heterogeneous, and the catalyst could be reused for the conversion of cyclohexanone oxime to aniline at least five times with keeping its high catalytic performance. Kinetic studies and several control experiments showed that the high activity and selectivity of the present catalyst system were attributed to the concerted catalysis of the basic LDH support and the active Pd species on LDH. The present transformation of cyclohexanone oximes to primary anilines proceeds through a dehydration/dehydrogenation sequence, and herein the plausible reaction mechanism is proposed on the basis of several pieces of experimental evidence
Dan Yang - One of the best experts on this subject based on the ideXlab platform.
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palladium ii catalyzed oxidative cascade cyclization reactions of Anilides and anilines scope and mechanistic investigations
ChemInform, 2011Co-Authors: Kaitai Yip, Dan YangAbstract:In the presence of the Pd(OAc)2/pyridine or quinoline catalyst system under an oxygen atmosphere, acrylAnilides or N-allylanilines are cyclized to form pyrrolo-fused indoles.
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palladium ii catalyzed oxidative cascade cyclization reactions of Anilides and anilines scope and mechanistic investigations
Chemistry-an Asian Journal, 2011Co-Authors: Kaitai Yip, Dan YangAbstract:With Pd(OAc)(2)/pyridine as the catalyst system and molecular oxygen as a green oxidant, acrylAnilides and N-allylanilines undergo oxidative cascade cyclization to form heterocyclic rings in high yields. This methodology is applicable to acrylAnilides of different substitution patterns on olefinic units. Mechanistic studies revealed that cyclization of acrylAnilides proceeded through an intramolecular syn-amidopalladation pathway. The reversible nature of amidopalladation serves as a "scavenging process" to prevent β-hydride elimination from occurring halfway through the catalytic cycle, thus favoring the formation of cascade cyclization products. In addition, internal coordination between an σ-alkylpalladium species and a tethered olefinic C=C double bond also appears to disfavor β-hydride elimination.
Kang Zhao - One of the best experts on this subject based on the ideXlab platform.
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Phenyliodine Bis(trifluoroacetate)-Mediated Oxidative C–C Bond Formation: Synthesis of 3-Hydroxy-2-oxindoles and Spirooxindoles from Anilides
2016Co-Authors: Junwei Wang, Yucheng Yuan, Rui Xiong, Daisy Zhang-negrerie, Kang ZhaoAbstract:The reaction of phenyliodine bis(trifluoroacetate) (PIFA) with a series of Anilides 1 (E = CO2Et) in CF3CH2OH was found to give 3-hydroxy-2-oxindole derivatives 2, while that with various Anilides 1′ (E = CON(R4)Ar) afforded the C2-symmetric or unsymmetric spirooxindoles 3. These processes feature a metal-free oxidative C(sp2)–C(sp3) bond formation, followed by oxidative hydroxylation or spirocyclization
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phenyliodine bis trifluoroacetate mediated oxidative c c bond formation synthesis of 3 hydroxy 2 oxindoles and spirooxindoles from Anilides
ChemInform, 2012Co-Authors: Junwei Wang, Yucheng Yuan, Rui Xiong, Daisy Zhangnegrerie, Kang ZhaoAbstract:Various Anilides bearing an ethoxycarbonyl group as terminal function can be transformed to the desired 3- hydroxy-2-oxindole structures.
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phenyliodine bis trifluoroacetate mediated oxidative c c bond formation synthesis of 3 hydroxy 2 oxindoles and spirooxindoles from Anilides
Organic Letters, 2012Co-Authors: Junwei Wang, Yucheng Yuan, Rui Xiong, Daisy Zhangnegrerie, Kang ZhaoAbstract:The reaction of phenyliodine bis(trifluoroacetate) (PIFA) with a series of Anilides 1 (E = CO2Et) in CF3CH2OH was found to give 3-hydroxy-2-oxindole derivatives 2, while that with various Anilides 1′ (E = CON(R4)Ar) afforded the C2-symmetric or unsymmetric spirooxindoles 3. These processes feature a metal-free oxidative C(sp2)–C(sp3) bond formation, followed by oxidative hydroxylation or spirocyclization.
Xiongjie Jin - One of the best experts on this subject based on the ideXlab platform.
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selective synthesis of primary anilines from nh3 and cyclohexanones by utilizing preferential adsorption of styrene on the pd nanoparticle surface
Angewandte Chemie, 2019Co-Authors: Yu Koizumi, Xiongjie Jin, Kyoko Nozaki, Noritaka Mizuno, Takafumi Yatabe, Ray Miyazaki, Junya Hasegawa, Kazuya YamaguchiAbstract:Dehydrogenative aromatization is one of the attractive alternative methods for directly synthesizing primary anilines from NH3 and cyclohexanones. However, the selective synthesis of primary anilines is quite difficult because the desired primary aniline products and the cyclohexanone substrates readily undergo condensation affording the corresponding imines (i.e., N-cyclohexylidene-anilines), followed by hydrogenation to produce N-cyclohexylanilines as the major products. In this study, primary anilines were selectively synthesized in the presence of supported Pd nanoparticle catalysts (e.g., Pd/HAP, HAP=hydroxyapatite, Ca10 (PO4 )6 (OH)2 ) by utilizing competitive adsorption unique to heterogeneous catalysis; in other words, when styrene was used as a hydrogen acceptor, which preferentially adsorbs on the Pd nanoparticle surface in the presence of N-cyclohexylidene-anilines, various structurally diverse primary anilines were selectively synthesized from readily accessible NH3 and cyclohexanones. The Pd/HAP catalyst was reused several times though its catalytic performance gradually declined.
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selective synthesis of primary anilines from cyclohexanone oximes by the concerted catalysis of a mg al layered double hydroxide supported pd catalyst
Journal of the American Chemical Society, 2017Co-Authors: Xiongjie Jin, Yu Koizumi, Kazuya Yamaguchi, Kyoko Nozaki, Noritaka MizunoAbstract:Although the selective conversion of cyclohexanone oximes to primary anilines would be a good complement to the classical synthetic methods for primary anilines, which utilize arenes as the starting materials, there have been no general and efficient methods for the conversion of cyclohexanone oximes to primary anilines until now. In this study, we have successfully realized the efficient conversion of cyclohexanone oximes to primary anilines by utilizing a Mg-Al layered double hydroxide supported Pd catalyst (Pd(OH)x/LDH) under ligand-, additive-, and hydrogen-acceptor-free conditions. The substrate scope was very broad with respect to both cyclohexanone oximes and cyclohexenone oximes, which gave the corresponding primary anilines in high yields with high selectivities (17 examples, 75% to >99% yields). The reaction could be scaled up (gram-scale) with a reduced amount of the catalyst (0.2 mol %). Furthermore, the one-pot synthesis of primary anilines directly from cyclohexanones and hydroxylamine was also successful (five examples, 66-99% yields). The catalysis was intrinsically heterogeneous, and the catalyst could be reused for the conversion of cyclohexanone oxime to aniline at least five times with keeping its high catalytic performance. Kinetic studies and several control experiments showed that the high activity and selectivity of the present catalyst system were attributed to the concerted catalysis of the basic LDH support and the active Pd species on LDH. The present transformation of cyclohexanone oximes to primary anilines proceeds through a dehydration/dehydrogenation sequence, and herein the plausible reaction mechanism is proposed on the basis of several pieces of experimental evidence.
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Selective Synthesis of Primary Anilines from Cyclohexanone Oximes by the Concerted Catalysis of a Mg–Al Layered Double Hydroxide Supported Pd Catalyst
2017Co-Authors: Xiongjie Jin, Yu Koizumi, Kazuya Yamaguchi, Kyoko Nozaki, Noritaka MizunoAbstract:Although the selective conversion of cyclohexanone oximes to primary anilines would be a good complement to the classical synthetic methods for primary anilines, which utilize arenes as the starting materials, there have been no general and efficient methods for the conversion of cyclohexanone oximes to primary anilines until now. In this study, we have successfully realized the efficient conversion of cyclohexanone oximes to primary anilines by utilizing a Mg–Al layered double hydroxide supported Pd catalyst (Pd(OH)x/LDH) under ligand-, additive-, and hydrogen-acceptor-free conditions. The substrate scope was very broad with respect to both cyclohexanone oximes and cyclohexenone oximes, which gave the corresponding primary anilines in high yields with high selectivities (17 examples, 75% to >99% yields). The reaction could be scaled up (gram-scale) with a reduced amount of the catalyst (0.2 mol %). Furthermore, the one-pot synthesis of primary anilines directly from cyclohexanones and hydroxylamine was also successful (five examples, 66–99% yields). The catalysis was intrinsically heterogeneous, and the catalyst could be reused for the conversion of cyclohexanone oxime to aniline at least five times with keeping its high catalytic performance. Kinetic studies and several control experiments showed that the high activity and selectivity of the present catalyst system were attributed to the concerted catalysis of the basic LDH support and the active Pd species on LDH. The present transformation of cyclohexanone oximes to primary anilines proceeds through a dehydration/dehydrogenation sequence, and herein the plausible reaction mechanism is proposed on the basis of several pieces of experimental evidence
Yves Janin - One of the best experts on this subject based on the ideXlab platform.
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On the Knorr synthesis of 6-bromo-4-methylquinolin-2(1H)-one
SYNTHESIS, 2011Co-Authors: Nicolas Wlodarczyk, Catherine Simenel, Muriel Delepierre, Jean-christophe Barale, Yves JaninAbstract:In the course of our work on infectious diseases, we were led to prepare 6-bromo-2-chloro-4-methylquinoline as a starting material. Since surprisingly little has been reported in the literature, the two synthetic steps to this compound were investigated. The synthesis involves a condensation between -ketoesters and 4-bromoaniline and the cyclization of the resulting Anilides into 6-bromoquinolin-2(1H)-one otherwise known as the Knorr reaction. The 1H NMR monitoring of the first step allowed us to optimize the conditions leading specifically to the anilide without the occurrence of the alternative crotonate. To illustrate the scope of our finding, few additional Anilides featuring electron attracting groups were prepared. The study of their cyclization revealed some unsuspected steric effect governing this second step. Aside from rectifying few claims in this chemistry, this study led to a three-step preparation of 6-bromo-2-chloro-4-methylquinoline in a 48 % overall yield from 4-bromoaniline.