3672-51-3Relevant academic research and scientific papers
3, 5-disubstituted isoxazole derivative and synthesis method thereof
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Paragraph 0011; 0023; 0033, (2021/08/14)
The invention provides a 3, 5-disubstituted isoxazole derivative and a synthesis method thereof, and belongs to the technical field of organic synthesis medicines and medical intermediates. The method comprises the following steps: adding a proper solvent
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
Complementary and Regioselective Synthesis of Isomeric 3-[Isoxazol-3(or 5)-yl]indoles from β-Ethylthio-β-indolyl-α,β-unsaturated Ketones
Yu, Haifeng,Wang, Kehua,Zhang, Xue,Wang, Wenju
, p. 1989 - 1999 (2021/01/21)
A simple and efficient method for the complementary and regioselective synthesis of isomeric 3-(isoxazol-5-yl)indoles and 3-(isoxazol-3-yl)indoles has been developed by the regioselective cyclocondensation reaction of β-ethylthio-β-indolyl-α,β-unsaturated ketones and hydroxylamine hydrochloride. It was found that the cyclocondensation reaction in the presence of excess NaOEt in refluxing EtOH gives 3-(isoxazol-5-yl)indoles in good yields, whereas using NaOAc in boiling AcOH gives 3-(isoxazol-3-yl)indoles in good yields.
Green preparation method of isoxazole compound participating in water-soluble vitamin E
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Paragraph 0133-0136, (2021/11/03)
The invention provides a green synthesis method of an isoxazole compound represented by the formula (III), wherein the aldehyde oxime compound represented by the formula (I) is a substrate and is in an aqueous solution of a surfactant with a mass concentration 1 wt % - 5 wt % in N - chlorosuccinimide. The alkyne compound represented by the formula (II) is reacted 6 - 16h at room temperature under the common action of the basic substance, and the resulting reaction solution is post-treated to obtain the isoxazole compound represented by the formula (III). Water serves as a reaction solvent, the use amount of the organic solvent is reduced, and zero emission of the solvent is realized.
One-pot regioselective synthesis of substituted pyrazoles and isoxazoles in PEG-400/water medium by Cu-free nano-Pd catalyzed sequential acyl Sonogashira coupling-intramolecular cyclization
Thirukovela, Narasimha Swamy,Balaboina, Ramesh,Botla, Vinayak,Vadde, Ravinder,Jonnalagadda, Sreekantha Babu,Vasam, Chandra Sekhar
, p. 6471 - 6481 (2019/11/20)
Catalyst efficacy of in situ generated Pd-nanoparticles (PdNPs) in the regioselective one-pot synthesis of 3,5-di & 3,4,5-trisubstituted pyrazoles and 3,5-disubstituted isoxazoles in environmentally benign PEG-400/H2O medium, which involves the sequential (i) Cu-free acyl-Sonogashira coupling (ASC) and (ii) intramolecular ynone-amine cyclization under PTC conditions was described. The results of controlled experiments support the operation of two sequential catalytic cycles (ASC/cyclization) and achievement of complementary/opposite regioselectivity via ynone-bound palladium in a one-pot approach. Moreover, the in situ PdNPs recovered after the first catalytic cycle of the one-pot reaction sequence have been reused again five times successively. Besides, prior to the above studies, the efficacy of some common Pd-N-heterocyclic carbene (Pd-NHC) complexes in catalyzing the same one-pot two-step reaction sequence (Cu-free ASC/cyclization) both in water and organic solvents was also optimized. In situ generation of PdNPs from above Pd-NHCs in water was also identified, but they are not reusable due to their large size distribution.
A Copper-Catalyzed Synthesis of Pyrroles through Photochemically Generated Acylazirines
Paternoga, Jan,Opatz, Till
, p. 7067 - 7078 (2019/11/14)
A synthesis of highly substituted 2,4-diacylpyrroles through a Cu-catalyzed dimerization of acylazirines generated in situ by a photochemical valence isomerization is described. The shown methodology allows the use of simple precursors and a readily avail
Rhodium-Catalyzed Cascade Annulative Coupling of 3,5-Diarylisoxazoles with Alkynes
Noguchi, Teppei,Nishii, Yuji,Miura, Masahiro
, p. 258 - 270 (2019/01/04)
A rhodium-catalyzed cascade annulative coupling of 3,5-diarylisoxazoles with three equivalents of an alkyne proceeds smoothly in the presence of a Cu(II) oxidant, where the sequential construction of isoquinoline and naphtho[1,8- bc ]pyran frameworks connected by a biaryl linkage is achieved by a single operation. Most of the obtained polycyclic compounds exhibit visible fluorescence in both the solution and the solid state. The hexaphenylated isoquinoline-naphthopyran conjugate (R = Ph) as a representative product shows a green emission which can be turned off by making an isoquinolinium salt with an acid. The emission is also reversibly turned on by treatment with a base.
An Intramolecular Wittig Approach toward Heteroarenes: Synthesis of Pyrazoles, Isoxazoles, and Chromenone-oximes
Khairnar, Pankaj V.,Lung, Tsai-Hui,Lin, Yi-Jung,Wu, Chi-Yi,Koppolu, Srinivasa Rao,Edukondalu, Athukuri,Karanam, Praneeth,Lin, Wenwei
supporting information, p. 4219 - 4223 (2019/06/17)
α-Halohydrazones/ketoximes are transformed into trisubstituted pyrazoles/disubstituted isoxazoles by treatment with phosphine, acyl chloride, and a base. Mechanistic investigations revealed the in situ formation of azo/nitroso olefin intermediates which underwent a tandem phospha-Michael/N- or O-acylation/intramolecular Wittig reaction to afford the heteroarenes in moderate to good yields. Further, proper functionalization of α-haloketoximes and a change of conditions allowed the chemoselective synthesis of chromenone-oximes as well as rearranged isoxazoles, thereby realizing a diversity-oriented synthesis.
General Platform for the Conversion of Isoxazol-5-ones to 3,5-Disubstituted Isoxazoles via Nucleophilic Substitutions and Palladium Catalyzed Cross-Coupling Strategies
Fernandes, Alessandra A. G.,da Silva, Amanda F.,Okada, Celso Y.,Suzukawa, Vitor,Cormanich, Rodrigo A.,Jurberg, Igor D.
, p. 3022 - 3034 (2019/05/17)
A general platform for the conversion of isoxazol-5-ones to 3,5-disubstituted isoxazoles has been developed via a two-step strategy. The first step leads to the formation of 5-(pseudo)halogenated isoxazoles, while in the second, a variety of heteroalkyl-, heteroaryl-, alkyl-, alkenyl-, alkynyl- and aryl-chains can be installed via nucleophilic substitutions or palladium catalyzed cross-coupling reactions.
Catalyst control in positional-selective C-H alkenylation of isoxazoles and a ruthenium-mediated assembly of trisubstituted pyrroles
Kumar, Pravin,Kapur, Manmohan
supporting information, p. 2134 - 2138 (2019/03/26)
High levels of catalyst control are demonstrated in determining the positional selectivity in C-H alkenylation of isoxazoles. A cationic rhodium-mediated, strong-directing group promotes C(sp2)-H activation at the proximal aryl ring whereas, the palladium-mediated electrophilic metallation leads to the C(sp2)-H activation at the distal position of the directing group. Synthetic elaboration of this C-H alkenylation product via ruthenium and copper co-catalysis leads to an efficient method for the assembly of densely substituted pyrroles.
