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Xiangping Hu - One of the best experts on this subject based on the ideXlab platform.
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ir catalyzed enantioselective hydrogenation of 2h 1 4 benzoxazines with a chiral 1 2 3 4 tetrahydro 1 Naphthylamine derived phosphine aminophosphine ligand
Chinese Journal of Chemistry, 2012Co-Authors: Juan Hu, Zhuo Zheng, Daoyong Wang, Xiangping HuAbstract:Unsymmetrical hybrid chiral phosphine-aminophosphine ligand derived from 1,2,3,4-tetrahydro-1-Naphthylamine has been found to be highly efficient in the Ir-catalyzed asymmetric hydrogenation of various 3-aryl-2H-1,4-benzoxazines, providing good enantioselectivities (up to 95% ee) and high catalytic activity (S/C up to 5000).
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modular phosphine aminophosphine ligands based on chiral 1 2 3 4 tetrahydro 1 Naphthylamine backbone a new class of practical ligands for enantioselective hydrogenations
Advanced Synthesis & Catalysis, 2008Co-Authors: Xiangping Hu, Daoyong Wang, Jiadi Huang, Saibo Yu, Jun Deng, Zhengchao DuanAbstract:A series of new chiral phosphine-aminophosphine ligands [(R)-HW-Phos] has been prepared from (R)-l.,2,3,4-tetrahydro-1-Naphthylamine through a two-step procedure, and successfully applied in the rhodium-catalyzed asymmetric hydrogenation of various functionalized olefins such as alpha-enol ester phosphonates, alpha-enamido phosphonates, (Z)-beta-(acylamino)acrylates and so on. Excellent enantioselectivities have been achieved in the hydrogenation of most substrates tested, demonstrating the high potential of these newly developed phosphine-aminophosphine ligands in asymmetric catalysis. The present research also discloses that these newly developed phosphine-aminophosphine ligands are more efficient than that derived from (S)-1-phenyl ethyl amine, suggesting that the increased rigidity conferred by a cyclohexyl fragment in these phosphine-aminophosphine ligands has a positive effect in the asymmetric induction.
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chiral 1 2 3 4 tetrahydro 1 Naphthylamine derived phosphine phosphoramidite ligand thnaphos application in highly enantioselective hydrogenations of functionalized cc bonds
Advanced Synthesis & Catalysis, 2008Co-Authors: Xiangping Hu, Daoyong Wang, Jiadi Huang, Saibo Yu, Zhengchao Duan, Jun Deng, Zhuo ZhengAbstract:We have recently reported a new chiral 1,2,3,4-tetrahydro-1-Naphthylamine-derived phosphine-phosphoramidite ligand, (R-c,R-a)-THNAPhos, that is highly efficient in the rhodium-catalyzed asymmetric hydrogenation of a broad range of alpha-enol ester phosphonates. To further demonstrate the utility of THNAPhos in asymmetric hydrogenation, in this paper, we describe its new application in the asymmetric hydrogenation of alpha-dehydroamino acid esters, enamides, dimethyl itaconate and alpha-enamido phosphonates. The results disclosed that the Rh/(R-c,R-a)-THNAPhos complex is highly effective for the enantioselective hydrogenation of these kinds of functionalized C=C olefins, affording the corresponding hydrogenation product in excellent enantioselectivities (normally over 99% ee).
S M Ashraf - One of the best experts on this subject based on the ideXlab platform.
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A short review on the synthesis, characterization, and application studies of poly(1-Naphthylamine): a seldom explored polyaniline derivative
Colloid and Polymer Science, 2017Co-Authors: Sapana Jadoun, Anurakshee Verma, S M Ashraf, Ufana RiazAbstract:Poly(1-Naphthylamine) (PNA) has been one of the seldom explored polyaniline (PANI) derivatives in spite of its versatile electrochromic and optoelectronic properties. The present review summarizes, for the first time, synthesis, characterization, and application studies related to poly(1-Naphthylamine) as well as its copolymers, blends, and nanocomposites that have been carried out during the past two decades. Details about the chemical as well as electrochemical techniques used for the synthesis of this polymer are provided along with various procedures adopted to improve its processibility via formulation of copolymers, blends, and nanocomposites. Recent studies dealing with the potential applications of this polymer in the field of catalysis and coatings are also evaluated.
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comparative studies of the photocatalytic and microwave assisted degradation of alizarin red using zno poly 1 Naphthylamine nanohybrids
Journal of Molecular Liquids, 2016Co-Authors: Ufana Riaz, S M Ashraf, Vaibhav Budhiraja, Sadaf Aleem, Jyoti KashyapAbstract:Abstract Semiconductors such as ZnO and TiO2 have been extensively utilized in the photocatalytic degradation of dyes. However till date, no study has been reported to compare the catalytic efficiency of such organic–inorganic hybrids under UV light and microwave irradiation separately. The present work reports the synthesis of poly(1-Naphthylamine)/ZnO nanohybrids. The structure and morphology of the synthesized nanocomposites were characterized using FT-IR, UV, XRD, TEM and Cyclic voltammetry analyses. The dye degradation studies were done separately in a photochemical reactor and in laboratory microwave oven and the fragments were identified using LC–MS technique. Results showed that under microwave irradiation, the efficiency of ZnO/PNA as catalyst was higher as compared to UV irradiation. Higher extent of •OH radical generation was confirmed in microwave as compared to UV irradiation which was found to be responsible for the high rate of degradation of dye solution. A plausible degradation pathway was proposed.
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Effect of pH on the microwave-assisted degradation of methyl orange using poly(1-Naphthylamine) nanotubes in the absence of UV–visible radiation
Colloid and Polymer Science, 2015Co-Authors: Ufana Riaz, S M Ashraf, Munazah FarooqAbstract:Microwave-assisted degradation of dyes is being extensively investigated for wastewater remediation. The present work reports, for the first time, degradation of methyl orange (MeO) in neutral, acidic, and basic media under microwave irradiation using semiconducting polymer [poly( 1 -Naphthylamine) (PNA)] nanotubes as catalyst in the absence of any light source. Degradation of the dye was followed spectrophotometrically and by total organic content (TOC) analysis. In the presence of poly( 1 -Naphthylamine), microwave irradiation in 15 min caused 70, 84, and 64 % degradation at 280 nm, while at 460 nm the degradation values were 80, 96 and 78 % of MO in neutral, acidic, and basic media, respectively. The degradation of the dye in the absence and presence of PNA catalyst and in acidic, basic, and neutral media followed first-order rate kinetics. Rate constant, k , values were found to be slightly dependent on the pH of the dye solutions. Liquid chromatography–mass spectroscopy analysis confirmed that dye degrades into smaller fragments of low molar masses.
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catalytic degradation of orange g under microwave irradiation with a novel nanohybrid catalyst
Journal of environmental chemical engineering, 2015Co-Authors: Ufana Riaz, S M Ashraf, Ankur RuhelaAbstract:Abstract Catalytic degradation of pollutants under simultaneous exposure to ultraviolet–visible and microwave irradiations ubiquitously in presence of semiconductor photcatalysts like TiO 2 have been found highly efficient. TiO 2 being the most prominent photocatalyst in the above process, poses environmental and health hazard due to its nano form. We therefore aim to develop an efficient catalyst for dye degradation by replacing the semiconductor photocatalyst with a polymer semiconductor-based nanohybrid and also ruling out exposure to UV irradiation. Nanohybrid of poly(1-Naphthylamine) (PNA) with bentonite (Bent) clay was synthesized under microwave irradiation. Fourier transform infrared spectroscopy revealed emeraldine form of PNA in the nanohybrid while ultraviolet–visible spectra established the conducting state of bentonite/poly(1-Naphthylamine) nanohybrid. Formation of vertical chains of PNA in the interlayer space of bentonite clay was established by X-ray diffraction and transmission electron microscopy showed core–shell structure of the bentonite/poly(1-Naphthylamine) nanohybrid with size in the range of 140–200 nm. Cyclic voltammetry studies showed that the nanohybrid was more electroactive than pure bentonite. Surface charge and surface area of the catalyst was determined to explain its catalytic activity. The nanohybrid catalyzed dye degradation under microwave irradiation at 30 °C and showed 2.0–2.7 times higher catalytic efficiency as compared to pure bentonite. Liquid chromatographic–mass spectroscopic results showed that dye was degraded rapidly into intermediates of low m/z values: 285, 143, 119, 113 and 60. The catalyst was usable to six cycles.
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latent photocatalytic behavior of semi conducting poly 1 Naphthylamine nanotubes in the degradation of comassie brilliant blue rg 250
Separation and Purification Technology, 2012Co-Authors: Ufana Riaz, S M AshrafAbstract:Abstract TiO 2 and ZnO have been extensively used as low price photocatalysts for the degradation of dyes. To enhance the photocatalytic activity of these inorganic oxides under the visible light irradiation, conducting polymers such as polyaniline (PANI) and its derivatives are generally used as photosensitizers. The present preliminary study explores, for the first time, the latent photocatalytic behavior of pure polymeric organic semiconductor – poly(1-Naphthylamine) (PNA) nanotubes in the degradation of Comassie Blue (CB) dye under solar irradiation. Pristine PNA has band gap energy of 2.11 eV which can facilitate the excitation of electrons from its valence band to conduction band under visible light irradiation. In order to enhance the e − /h + separation and to prevent their recombination, simultaneous ultrasonic irradiation was used. Ultrasonic irradiation was found to accelerate the photodegradation and mineralization of CB dye. Sonophotocatalysis and sonolysis exhibited pseudo first order rate kinetics which was found to be in agreement with Langmuir Hinshelwood equation. The mechanism of sonophotocatalytic degradation and tentative photodegradation pathways have been proposed.
Daoyong Wang - One of the best experts on this subject based on the ideXlab platform.
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ir catalyzed enantioselective hydrogenation of 2h 1 4 benzoxazines with a chiral 1 2 3 4 tetrahydro 1 Naphthylamine derived phosphine aminophosphine ligand
Chinese Journal of Chemistry, 2012Co-Authors: Juan Hu, Zhuo Zheng, Daoyong Wang, Xiangping HuAbstract:Unsymmetrical hybrid chiral phosphine-aminophosphine ligand derived from 1,2,3,4-tetrahydro-1-Naphthylamine has been found to be highly efficient in the Ir-catalyzed asymmetric hydrogenation of various 3-aryl-2H-1,4-benzoxazines, providing good enantioselectivities (up to 95% ee) and high catalytic activity (S/C up to 5000).
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novel chiral phosphine phosphoramidite ligands derived from 1 Naphthylamine for highly efficient rh catalyzed asymmetric hydrogenation
ChemInform, 2009Co-Authors: Daoyong Wang, Jiadi Huang, Zhengchao Duan, Jun Deng, Zhuo ZhengAbstract:A new chiral phosphine-phosphoramidite ligand (S)-HY-Phos 1 has been prepared from 1-Naphthylamine via a two-step transformation, and successfully applied in the Rh-catalyzed asymmetric hydrogenation of various functionalized olefins, including α-(acetamido)cinnamates, enamides and α-enol ester phosphonates, in which up to 98% ee, 99% ee and 99% ee were achieved, respectively.
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modular phosphine aminophosphine ligands based on chiral 1 2 3 4 tetrahydro 1 Naphthylamine backbone a new class of practical ligands for enantioselective hydrogenations
Advanced Synthesis & Catalysis, 2008Co-Authors: Xiangping Hu, Daoyong Wang, Jiadi Huang, Saibo Yu, Jun Deng, Zhengchao DuanAbstract:A series of new chiral phosphine-aminophosphine ligands [(R)-HW-Phos] has been prepared from (R)-l.,2,3,4-tetrahydro-1-Naphthylamine through a two-step procedure, and successfully applied in the rhodium-catalyzed asymmetric hydrogenation of various functionalized olefins such as alpha-enol ester phosphonates, alpha-enamido phosphonates, (Z)-beta-(acylamino)acrylates and so on. Excellent enantioselectivities have been achieved in the hydrogenation of most substrates tested, demonstrating the high potential of these newly developed phosphine-aminophosphine ligands in asymmetric catalysis. The present research also discloses that these newly developed phosphine-aminophosphine ligands are more efficient than that derived from (S)-1-phenyl ethyl amine, suggesting that the increased rigidity conferred by a cyclohexyl fragment in these phosphine-aminophosphine ligands has a positive effect in the asymmetric induction.
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chiral 1 2 3 4 tetrahydro 1 Naphthylamine derived phosphine phosphoramidite ligand thnaphos application in highly enantioselective hydrogenations of functionalized cc bonds
Advanced Synthesis & Catalysis, 2008Co-Authors: Xiangping Hu, Daoyong Wang, Jiadi Huang, Saibo Yu, Zhengchao Duan, Jun Deng, Zhuo ZhengAbstract:We have recently reported a new chiral 1,2,3,4-tetrahydro-1-Naphthylamine-derived phosphine-phosphoramidite ligand, (R-c,R-a)-THNAPhos, that is highly efficient in the rhodium-catalyzed asymmetric hydrogenation of a broad range of alpha-enol ester phosphonates. To further demonstrate the utility of THNAPhos in asymmetric hydrogenation, in this paper, we describe its new application in the asymmetric hydrogenation of alpha-dehydroamino acid esters, enamides, dimethyl itaconate and alpha-enamido phosphonates. The results disclosed that the Rh/(R-c,R-a)-THNAPhos complex is highly effective for the enantioselective hydrogenation of these kinds of functionalized C=C olefins, affording the corresponding hydrogenation product in excellent enantioselectivities (normally over 99% ee).
Saibo Yu - One of the best experts on this subject based on the ideXlab platform.
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modular phosphine aminophosphine ligands based on chiral 1 2 3 4 tetrahydro 1 Naphthylamine backbone a new class of practical ligands for enantioselective hydrogenations
Advanced Synthesis & Catalysis, 2008Co-Authors: Xiangping Hu, Daoyong Wang, Jiadi Huang, Saibo Yu, Jun Deng, Zhengchao DuanAbstract:A series of new chiral phosphine-aminophosphine ligands [(R)-HW-Phos] has been prepared from (R)-l.,2,3,4-tetrahydro-1-Naphthylamine through a two-step procedure, and successfully applied in the rhodium-catalyzed asymmetric hydrogenation of various functionalized olefins such as alpha-enol ester phosphonates, alpha-enamido phosphonates, (Z)-beta-(acylamino)acrylates and so on. Excellent enantioselectivities have been achieved in the hydrogenation of most substrates tested, demonstrating the high potential of these newly developed phosphine-aminophosphine ligands in asymmetric catalysis. The present research also discloses that these newly developed phosphine-aminophosphine ligands are more efficient than that derived from (S)-1-phenyl ethyl amine, suggesting that the increased rigidity conferred by a cyclohexyl fragment in these phosphine-aminophosphine ligands has a positive effect in the asymmetric induction.
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chiral 1 2 3 4 tetrahydro 1 Naphthylamine derived phosphine phosphoramidite ligand thnaphos application in highly enantioselective hydrogenations of functionalized cc bonds
Advanced Synthesis & Catalysis, 2008Co-Authors: Xiangping Hu, Daoyong Wang, Jiadi Huang, Saibo Yu, Zhengchao Duan, Jun Deng, Zhuo ZhengAbstract:We have recently reported a new chiral 1,2,3,4-tetrahydro-1-Naphthylamine-derived phosphine-phosphoramidite ligand, (R-c,R-a)-THNAPhos, that is highly efficient in the rhodium-catalyzed asymmetric hydrogenation of a broad range of alpha-enol ester phosphonates. To further demonstrate the utility of THNAPhos in asymmetric hydrogenation, in this paper, we describe its new application in the asymmetric hydrogenation of alpha-dehydroamino acid esters, enamides, dimethyl itaconate and alpha-enamido phosphonates. The results disclosed that the Rh/(R-c,R-a)-THNAPhos complex is highly effective for the enantioselective hydrogenation of these kinds of functionalized C=C olefins, affording the corresponding hydrogenation product in excellent enantioselectivities (normally over 99% ee).
Etsuji Okada - One of the best experts on this subject based on the ideXlab platform.
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a concise synthesis of fluorine containing benzo h quinolines and benzo h quinolones by selective pyridine and pyridinone rings formation reactions of n propargyl 2 4 bis trifluoroacetyl 1 Naphthylamine with various active methylene compounds
Heterocycles, 2010Co-Authors: Etsuji Okada, Dai Shibata, Norikado Tsukushi, Masato Dohura, Satoru Adachi, Maurice MedebielleAbstract:N-Propargyl-2,4-bis(trifluoroacetyl)-1-Naphthylamine (3) underwent nitrogen-containing heterocyclic ring-formation reactions with a variety of active methylene compounds in the presence of sodium alkoxides. This annulation reactions with dialkyl malonates were highly dependent on reaction temperature to give selectively the corresponding fluorine-containing benzo[h]quinolines (5) at high temperature and 1H-benzo[h]quinolin-2-ones (7 and 8) at low temperature. Furthermore, changing the electron-withdrawing groups of active methylene compounds led to alternation of the reactive site wherein the reagents attack first and to the formation of the different nitrogen-containing heterocyclic systems, pyridine (9), dihydropyridine (11 and 13) and pyridone (12).
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an efficient and selective synthetic method for fluorine containing benzo h quinolines and 1h benzo h quinolin 2 ones from n propargyl 2 4 bis trifluoroacetyl 1 Naphthylamine
Heterocycles, 2009Co-Authors: Etsuji Okada, Dai Shibata, Norikado Tsukushi, Masato Dohura, Maurice MedebielleAbstract:N-Propargyl-2,4-bis(trifluoroacetyl)-1-Naphthylamine (3) underwent nitrogen-containing heterocyclic ring-formation reactions with active methylene compounds such as dialkyl malonates in the presence of sodium alkoxides. This ring closure reactions were very dependent on reaction temperature to give selectively the corresponding fluorine-containing benzo[h]quinolines (5) at high temperature and 1H-benzo[h]quinolin-2-ones (7 and 8) at low temperature.
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synthesis and aromatic nucleophilic n n n s and n o exchange reactions of n n dimethyl 2 trifluoroacetyl 1 Naphthylamine
Tetrahedron Letters, 2003Co-Authors: Etsuji Okada, Maurice Medebielle, Yoshihiro Otsuki, Megumi Shinohara, Yuhei Shimizu, Hiroshi TakeuchiAbstract:Abstract We succeeded in the synthesis of N , N -dimethyl-2-trifluoroacetyl-1-Naphthylamine ( 10 ) by the regioselective deacylation of N , N -dimethyl-2,4-bis(trifluoroacetyl)-1-Naphthylamine with trifluoroacetic acid and water. The aromatic nucleophilic substitutions of 10 with various amines, thiols and alcohols proceeded cleanly to give the corresponding N – N , N – S and N – O exchanged products in moderate to excellent yields.
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facile and convenient synthetic methods for fluorine containing benzo c thioxanthenes and benzo c xanthenes from n n dimethyl 1 Naphthylamine
Synthesis, 1992Co-Authors: Etsuji Okada, Ryoichi Masuda, Nobuyuki Imazaki, Masaru Hojo, Koichi TakahashiAbstract:Aromatic nucleophilic N-S and N-O exchange reactions of N,N-dimethyl-2,4-bis(trifluoroacetyl)-1-Naphthylamine (1) with thiophenols and phenols gave the corresponding 2,4-bis(trifluoroacetyl)-1-(arylthio) naphthalenes 2 and -1-(4-methoxyphenoxy) naphthalene (5) in moderate to excellent yields. Acid-catalyzed cyclization reactions of 2 and 5 afforded fluorine-containing 7H-benzo[c]thioxanthenes 3,4 and 7H-benzo[c]xanthenes 6,7, respectively, in high yields
