- Electrophilic addition of alcohols to 1-vinyl-2-phenylazopyrroles and unexpected formation of 2-methylquinoline
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1-Vinyl-2-phenylazopyrroles react with alcohols in the presence of acids or PdCl2 to give 1-(1-alkoxyethyl)-2-phenylazopyrroles in up to 49% yield. In the presence of trifluoroacetic acid 2-methylquinoline unexpectedly formed (yield up to 26%) involving into the reaction the phenylazo and 1-vinyl groups.
- Shmidt,Senotrusova,Ushakov,Protsuk,Mikhaleva,Trofimov
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Read Online
- Low-Temperature Nickel-Catalyzed C?N Cross-Coupling via Kinetic Resolution Enabled by a Bulky and Flexible Chiral N-Heterocyclic Carbene Ligand
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The transition-metal-catalyzed C?N cross-coupling has revolutionized the construction of amines. Despite the innovations of multiple generations of ligands to modulate the reactivity of the metal center, ligands for the low-temperature enantioselective amination of aryl halides remain a coveted target of catalyst engineering. Designs that promote one elementary reaction often create bottlenecks at other steps. We here report an unprecedented low-temperature (as low as ?50 °C), enantioselective Ni-catalyzed C?N cross-coupling of aryl chlorides with sterically hindered secondary amines via a kinetic resolution process (s factor up to >300). A bulky yet flexible chiral N-heterocyclic carbene (NHC) ligand is leveraged to drive both oxidative addition and reductive elimination with low barriers and control the enantioselectivity. Computational studies indicate that the rotations of multiple σ-bonds on the C2-symmetric chiral ligand adapt to the changing needs of catalytic processes. We expect this design would be widely applicable to diverse transition states to achieve other challenging metal-catalyzed asymmetric cross-coupling reactions.
- Hong, Xin,Shi, Shi-Liang,Wang, Zi-Chao,Xie, Pei-Pei,Xu, Youjun
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supporting information
p. 16077 - 16084
(2021/06/17)
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- Facile synthesis of 2-methylquinolines from anilines on mesoporous N-doped TiO2 under UV and visible light
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Nitrogen-doped TiO2 was synthesized by a simple wet method using a nitrogen precursor hydrazine hydrate and nano TiO2. This photocatalyst was characterized by X-ray diffraction, highresolution transmission electron microscopy, diffused reflectance spectra, photoluminescence, and X-ray photoelectron spectroscopy. XPS analysis indicates the incorporation of anionic nitrogen in TiO2 lattice as O-Ti-N linkage. N2 adsorption-desorpion isotherm indicates the mesoporous nature of N-TiO2 with the surface area 130.0 m2/g. Sizes of N-TiO2 particles are found to be in the range of 5-30 nm by HRTEM images. DRS spectra reveal the extended absorption to the visible range. N-TiO2 is found to be more efficient than Ag-TiO2, Au-TiO2, and Pt-TiO2 in quinaldine synthesis under visible light. Copyright Taylor & Francis Group, LLC.
- Selvam,Swaminathan
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p. 500 - 508
(2013/05/21)
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- Nano Pt-TiO2 for an efficient one-pot photocatalytic synthesis of quinaldines from anilines and ethanol
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Nanosized platinum particles loaded on the TiO2 nanoparticles were prepared to assess its photocatalytic activity in simple one-pot synthesis of quinaldines from anilines in ethanol using UV light. The catalyst was characterized by X-ray diffra
- Selvam, Kaliyamoorthy,Sreedhar, Bojja,Swaminathan, Meenakshisundaram
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experimental part
p. 761 - 773
(2012/08/07)
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- Au-doped TiO2 nanoparticles for selective photocatalytic synthesis of quinaldines from anilines in ethanol
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A convenient eco-friendly photocatalytic synthesis of quinaldines has been developed by a simple one-pot reaction of anilines in ethanol solution with Au-loaded TiO2 under UV irradiation. Upon irradiation in the presence of Au-TiO2, aniline and oxidation products derived from ethanol undergo condensation-cyclization to afford quinaldines.
- Selvam,Swaminathan
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scheme or table
p. 4911 - 4914
(2010/10/02)
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- Synthesis of novel quinaldine-based squaraine dyes: Effect of substituents and role of electronic factors
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(Chemical Equation Presented) Condensation of squaric acid with quinaldinium salts containing electron-donating substituents gave only the semisquaraines. However, with salts possessing electronegative and electron-withdrawing groups, the squaraine dyes were isolated in quantitative yields. The semisquaraines formed undergo condensation with highly nucleophilic salts yielding the unsymmetrical squaraine dyes. These results demonstrate the role of electronic factors and provide valuable information for the design of efficient squaraine-based sensitizers that can have potential applications in photodynamic therapy.
- Jyothish, Kuthanapillil,Arun, Kalliat T.,Ramaiah, Danaboyina
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p. 3965 - 3968
(2007/10/03)
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