5262-62-4Relevant academic research and scientific papers
TEMPO-Mediated Selective Synthesis of Isoxazolines, 5-Hydroxy-2-isoxazolines, and Isoxazoles via Aliphatic δ-C(sp3)-H Bond Oxidation of Oximes
Mondal, Santanu,Biswas, Sourabh,Ghosh, Krishna Gopal,Sureshkumar, Devarajulu
, p. 2439 - 2446 (2021/08/03)
Selective synthesis of three different bioactive heterocycles; isoxazolines, 5-hydroxy-2-isoxazolines and isoxazoles from the same starting material using TEMPO (2,2,6,6-Tetramethylpiperidin-1-oxyl) as a radical initiator is reported. Selectivity was achi
Iron(iii)-catalyzed selective N-O bond cleavage to prepare tetrasubstituted pyridines and 3,5-disubstituted isoxazolines from: N -vinyl-α,β-unsaturated ketonitrones
Chen, Chun-Hua,Wu, Qing-Yan,Wei, Cui,Liang, Cui,Su, Gui-Fa,Mo, Dong-Liang
supporting information, p. 2722 - 2729 (2018/06/29)
An iron(iii)-catalyst controlled cyclization and selective N-O bond cleavage of N-vinyl-α,β-unsaturated nitrones has been achieved under mild conditions to access tetrasubstituted pyridines and 3,5-disubstituted isoxazolines in moderate to good yields. The tetrasubstituted pyridines were afforded with FeCl3 as a catalyst while using FeCl3·6H2O combined with 1,10-phenanthroline delivered isoxazolines. The regioselectivity for cyclization of styrenyl groups in N-vinyl-α,β-unsaturated nitrones was completely different during the formation of pyridines and isoxazolines. A rational mechanism for the formation of pyridines and isoxazolines was proposed based on the further control experimental studies. The isoxazolines can be converted to a novel bidentate N-ligand over four steps and an epoxypyridine scaffold was obtained from N-vinyl nitrone when copper(ii) acetate in combination with the prepared bidentate N-ligand was used.
Selectfluor-Bu4NI-Mediated C(sp3)-H Oxidation in Aqueous Media: Synthesis of Δ2-Isoxazolines from Oximes
Shi, Di,Qin, Hai-Tao,Zhu, Chen,Liu, Feng
, p. 5084 - 5088 (2015/08/18)
The direct functionalization of an aliphatic C-H bond within a complex molecule through a free-radical pathway is a valuable tool in synthetic chemistry. Herein, we developed an efficient transition-metal-free approach to generate Δ2-isoxazolines from oximes by radical-mediated C(sp3)-H oxidation. Investigation of the mechanism suggested that in the presence of Selectfluor and Bu4NI, the homolysis of the in situ formed O-I bond generated an iminoxyl radical that facilitated subsequent 1,5-H transfer and C(sp3)-H oxidation. The title reaction involves Selectfluor-Bu4NI-mediated C-O bond formation in aqueous media under metal-free conditions. A variety of Δ2-isoxazolines are directly synthesized from oximes by remote intramolecular functionalization of C(sp3)-H bonds.
An environmentally benign synthesis of isoxazolines and isoxazoles mediated by potassium chloride in water
Han, Liuquan,Zhang, Bijun,Zhu, Min,Yan, Jie
supporting information, p. 2308 - 2311 (2014/04/17)
An effective and environmentally benign procedure for the synthesis of isoxazolines and isoxazoles has been developed by a cycloaddition of nitrile oxides with alkenes or alkynes in water. In this approach, potassium chloride is first oxidized into chlorine in water by the environmentally friendly oxidant Oxone, then aldoximes are oxidized into nitrile oxides by the in situ generated hypochlorous acid, finally a 1,3-dipolar cycloaddition between nitrile oxides and alkenes or alkynes occurs to provide the corresponding isoxazolines and isoxazoles in good yields.
One-pot synthesis of isoxazolines from aldehydes catalyzed by iodobenzene
Han, Liuquan,Zhang, Bijun,Xiang, Changbin,Yan, Jie
, p. 503 - 509 (2014/03/21)
A convenient one-pot, three-step procedure for the synthesis of isoxazolines starting from aldehydes has been developed involving catalytic cycloaddition between nitrile oxides and alkenes, in which iodobenzene is used as the catalyst for the in situ generation of a hypervalent iodine intermediate. In this approach, the aldehydes are first transformed with hydroxylamine sulfate into aldoximes, which are then oxidized to nitrile oxides by the in situ generated hypervalent iodine intermediate; finally, a 1,3-dipolar cycloaddition between the nitrile oxides and alkenes occurs to provide the isoxazolines in moderate to good yields.
Beyond azide-alkyne click reaction: Easy access to 18F-labelled compounds via nitrile oxide cycloadditions
Zlatopolskiy, Boris D.,Kandler, Rene,Kobus, Diana,Mottaghy, Felix M.,Neumaier, Bernd
supporting information; experimental part, p. 7134 - 7136 (2012/07/27)
Radiofluorinated 4-fluorobenzonitrile oxide and N-hydroxy-4- fluorobenzimidoyl chloride rapidly react with different alkenes and alkynes under mild conditions. These cycloadditions are suitable for the preparation of low-molecular weight radiopharmaceutic
