- Direct and Co-catalytic Oxidation of Hydroxylamines to Nitrones Promoted by Rhodium Nanoparticles Supported on Carbon Nanotubes
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Rhodium nanoparticles were assembled on carbon nanotubes, and the resulting nanohybrid was studied in the aerobic oxidation of hydroxylamines to nitrones. Two catalytic systems were developed (i.e., direct or co-catalytic) and both operated to provide high yields of the products, under mild conditions, but with their own specificity as regards the kinetics and regioselectivity of the transformation. In addition, the in situ cycloaddition of the produced nitrones with different alkynes was investigated.
- Prakash, Praveen,Gravel, Edmond,Nguyen, Dinh-Vu,Namboothiri, Irishi N. N.,Doris, Eric
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- Accessing benzooxadiazepines: Via formal [4 + 3] cycloadditions of aza- o -quinone methides with nitrones
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An unprecedented and efficient [4 + 3] cycloaddition of N-(ortho-chloromethyl)aryl amides with nitrones has been developed. This approach provides easy access to a series of seven-membered benzooxadiazepine derivatives in good to excellent yields (up to 99% yield) under mild reaction conditions.
- Zheng, Yong-Sheng,Tu, Liang,Gao, Li-Mei,Huang, Rong,Feng, Tao,Sun, Huan,Wang, Wen-Xuan,Li, Zheng-Hui,Liu, Ji-Kai
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p. 2639 - 2642
(2018/04/27)
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- Triphenylbismuth carbonate-mediated oxidation of hydroxylamines to nitrones and: In situ 1,3-dipolar cycloaddition
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Triphenylbismuth carbonate was shown to act as a mild, selective and efficient reagent for the oxidation of hydroxylamines. The developed reaction conditions were shown to be compatible with the in situ trapping of the produced nitrones by a strained alkyne, via a [3 + 2] cycloaddition reaction.
- Nguyen, Dinh-Vu,Prakash, Praveen,Gravel, Edmond,Doris, Eric
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p. 89238 - 89241
(2016/10/03)
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- 1,3-Dipolar cycloaddition of N-substituted dipolarophiles and nitrones: Highly efficient solvent-free reaction
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(Chemical Equation Presented) New isoxazolidines were synthesized in good to excellent yields by 1,3-dipolar cycloaddition of N-vinylamide dipolarophiles and nitrones. Strikingly, solvent-free conditions gave high conversion and yields, shortened reaction time, and minimized degradation products. N-Vinyloxazolidin-2-one and its analogues used in these cycloaddition reactions were conveniently prepared in excellent yields by a modified version of Buchwald's one-step copper-catalyzed vinylation using vinyl bromide. From the adducts, a two-step access to various unsymmetric aspartate derivatives was also described.
- Thanh, Binh Nguyen,Martel, Arnaud,Dhal, Robert,Dujardin, Gilles
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p. 2621 - 2632
(2008/09/19)
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- Solid-phase synthesis of hydroxypiperazine derivatives using phenethylamine linker by oxidation-Cope elimination
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A general method is reported for the parallel solid-phase synthesis of hydroxypiperazine derivatives based on the oxidation-Cope elimination of polymer-bound phenethylamine linker with m-CPBA. The key intermediate of phenethylamine N-oxide resins was separable on solid-phase for subsequent β-elimination, from which the desired hydroxypiperazine products could be obtained in high purities and yields without any significant contamination at 90°C for 2 h. The utility of the methodology for solid-phase synthesis of general hydroxylamines was also investigated using the same linker. The progress of reactions could be monitored on polymer bound intermediates by ATR-FTIR spectroscopy on single bead. The desired products were obtained in good six-step overall yields upon cleavage from the resins and were characterized by LC/MS, 1H NMR, and 13C NMR spectroscopy.
- Seo, Jin-Soo,Kim, Hye-Won,Cheol, Min Yoon,Deok, Chan Ha,Gong, Young-Dae
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p. 9305 - 9311
(2007/10/03)
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