- TEMPO-Mediated Selective Synthesis of Isoxazolines, 5-Hydroxy-2-isoxazolines, and Isoxazoles via Aliphatic δ-C(sp3)-H Bond Oxidation of Oximes
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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
- Mondal, Santanu,Biswas, Sourabh,Ghosh, Krishna Gopal,Sureshkumar, Devarajulu
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p. 2439 - 2446
(2021/08/03)
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- A convenient one-pot synthesis of 3,5-diarylisoxazoles via oxidative cyclisation using catalytic CuBr2 and oxone
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A facile one-pot synthesis of 3,5-diarylisoxazoles from α,β-unsaturated ketones and hydroxylamine hydrochloride is reported. The reaction is efficiently promoted by catalytic CuBr2 and Oxone to afford the desired products mostly in high yields
- Bhatt, Ashish,Singh, Rajesh K.,Kant, Ravi
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supporting information
p. 1143 - 1147
(2019/03/26)
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- 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
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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.
- Thirukovela, Narasimha Swamy,Balaboina, Ramesh,Botla, Vinayak,Vadde, Ravinder,Jonnalagadda, Sreekantha Babu,Vasam, Chandra Sekhar
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p. 6471 - 6481
(2019/11/20)
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- General Platform for the Conversion of Isoxazol-5-ones to 3,5-Disubstituted Isoxazoles via Nucleophilic Substitutions and Palladium Catalyzed Cross-Coupling Strategies
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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.
- Fernandes, Alessandra A. G.,da Silva, Amanda F.,Okada, Celso Y.,Suzukawa, Vitor,Cormanich, Rodrigo A.,Jurberg, Igor D.
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p. 3022 - 3034
(2019/05/17)
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- Trichloroisocyanuric acid mediated one-pot synthesis of 3,5-diarylisoxazoles from α,β-unsaturated ketones
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A facile one-pot synthesis of 3,5-diarylisoxazoles from α,β-unsaturated ketones and hydroxylamine hydrochloride is reported. The reaction is efficiently promoted by trichloroisocyanuric acid (TCCA) to afford the desired products, mostly in high yields and
- Bhatt, Ashish,Singh, Rajesh K.,Kant, Ravi
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p. 1083 - 1091
(2019/04/01)
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- An Intramolecular Wittig Approach toward Heteroarenes: Synthesis of Pyrazoles, Isoxazoles, and Chromenone-oximes
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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.
- Khairnar, Pankaj V.,Lung, Tsai-Hui,Lin, Yi-Jung,Wu, Chi-Yi,Koppolu, Srinivasa Rao,Edukondalu, Athukuri,Karanam, Praneeth,Lin, Wenwei
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supporting information
p. 4219 - 4223
(2019/06/17)
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- Synthesis of Isoxazolines and Isoxazoles via Metal-Free Desulfitative Cyclization
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A novel, one-pot reaction for the synthesis of isoxazolines and isoxazoles is developed via a cascade process under metal-free conditions. The approach involves the formation of intramolecular C-N and C-O bonds and intermolecular C-C bonds from aromatic alkenes or alkynes and N -hydroxysulfonamides using hypervalent iodine(VII) and iodine as the oxidant. Activation of C-H and C-C bonds/construction of C-O bonds/elimination of SO 2 /C-N bond formation is achieved in sequence in the reaction system.
- Cheng, Jiaxin,Yang, Ze,Li, Yuansheng,Xi, Yulan,Sun, Qiu,He, Ling
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p. 2385 - 2393
(2018/05/28)
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- TBAI-catalyzed intramolecular annulation of chalcone oximes toward isoxazoles
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A TBAI-catalyzed intramolecular annulation of chalcone oximes toward isoxazoles was developed, providing 3,5-diarylisoxazoles in good yields. Functional groups such as methoxy, ethyoxyl, chloro, bromo, fluoro and nitro were well tolerated in this reaction
- Abdukader, Ablimit,Sun, Yadong,Zhang, Zengpeng,Liu, Chenjiang
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- Copper-catalyzed aerobic oxidative C-O bond formation for the synthesis of 3,5-disubstituted isoxazoles from enone oximes
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A direct access to 3,5-disubstituted isoxazoles has been accomplished through an intramolecular oxidative coupling reaction of enone oximes using a catalytic quantity of Cu(OAc)2. This method features an inexpensive metal catalyst, molecular ox
- Sun, Yadong,Abdukader, Ablimit,Zhang, Haiyan,Yang, Wanle,Liu, Chenjiang
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p. 55786 - 55789
(2017/12/26)
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- Preparation of 3,5-disubstituted pyrazoles and isoxazoles from terminal alkynes, aldehydes, hydrazines, and hydroxylamine
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The reaction of terminal alkynes with n-BuLi, and then with aldehydes, followed by the treatment with molecular iodine, and subsequently hydrazines or hydroxylamine provided the corresponding 3,5-disubstituted pyrazoles or isoxazoles in good yields with high regioselectivity, through the formations of propargyl secondary alkoxides and α-alkynyl ketones. The present reactions are one-pot preparation of 3,5-disubstituted pyrazoles from terminal alkynes, aldehydes, molecular iodine, and hydrazines, and 3,5-disubstituted isoxazoles from terminal alkynes, aldehydes, molecular iodine, and hydroxylamine.
- Harigae, Ryo,Moriyama, Katsuhiko,Togo, Hideo
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p. 2049 - 2058
(2014/04/03)
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- O-iodoxy benzoic acid–mediated synthesis of 3,5-diarylisoxazoles and isoxazole-3-carboxylic acids
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A new, convenient, ecofriendly synthesis of 3,5-diarylisoxazoles is reported from a,b-unsaturated ketoximes. Similarly, a novel synthesis of isoxazole carboxylic acids is also reported. Both the methods use efficient, environmentally friendly, and nontoxic iodoxybenzoic acid (IBX) as an oxidative cyclizing reagent. Easy procedure, environmentally benign reaction conditions, and nontoxicity are advantages to the methodology.
- Desai, Vidya G.,Naik, Sneha R.,Dhumaskar, Kashinath L.
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p. 1453 - 1460
(2016/09/23)
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- Synthesis of 3,5-diarylisoxazoles under solvent-free conditions using iodobenzene diacetate
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A simple and efficient method has been developed for conversion of chalcone oximes to 3,5-diaryl isoxazoles in excellent yields under solvent-free conditions. The synthesized compounds were characterized by infrared spectroscopy, 1H NMR, 13C NMR and HRMS.
- Chandra Sekhar, Kondapalli Venkata Gowri,Sasank, Thripuraribhatla Venkata Naga Varuna Tara,Nagesh, Hunsur Nagendra,Suresh, Narva,Naidu, Kalaga Mahalakshmi,Suresh, Amaroju
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p. 1045 - 1048
(2014/01/06)
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- Regioselective synthesis of polysubstituted pyrazoles and isoxazoles
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A regioselective synthesis has been developed for the preparation of unsymmetrical 1,3,5-triaryl-4-alkylpyrazolines and -pyrazoles by treatment of α-benzotriazolyl-α,β-unsaturated ketones with monosubstituted hydrazines followed by alkylation at the 4-position of the pyrazoline ring. Reaction of α-benzotriazolyl-α,β-unsaturated ketones with hydroxylamine gives 3,5-disubstituted isoxazoles regioselectively.
- Katritzky,Wang,Zhang,Voronkov,Steel
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p. 6787 - 6791
(2007/10/03)
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- On the Oximation of Diaryl-β-diketones
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The reaction of asymmetrically substituted β-diketones with hydroxylamine to give 3,5-diarylisoxazoles has been re-investigated, and has been found to occur with a low degree of site-selectivity unless steric effects are operating.The isoxazole that has t
- Bandiera, T.,Gruenanger, P.,Albini, F. Marinone
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p. 1423 - 1428
(2007/10/02)
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- A convenient preparation of 3,5-diarylisoxazoles
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3,5-Diarylisoxazoles 2a-i were prepared in moderate to high yields 51-94%) by oxidation of chalcone oximes with a new metal complex oxidant, tetrakis(pyridine)cobalt(II) dichromate (TPCD).
- Wei,Fang,Hu,Hu
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p. 1205 - 1206
(2007/10/02)
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- SYNTHESIS AND PROPERTIES OF AZOLES AND THEIR DERIVATIVES. PART XX. STUDIES ON THE THERMOLYSIS OF REGIO AND STEREOISOMERIC DIARYLNITRO-Δ2-ISOXAZOLINES
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Thermolysis of stereoisomeric 3,5-diaryl-4-nitro-Δ2-isoxazolines 1, 3, depending on the applied solvent, leads to 3,5-diarylisoxazoles 4 or mixtures of 3,5-diarylisoxazoles 4 and 3,5-diaryl-4-nitroisoxazoles 6.Under similar conditions, 3,4-diar
- Baranski, Andrzej,Cholewka, Elzbieta
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p. 483 - 494
(2007/10/02)
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- Lead Tetraacetate Oxidation of Chalcone Oximes
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Chalcone oximes (Ia-e) are oxidised by lead tetraacetate in dry benzene to afford the parent ketones (IIa-e) and the corresponding isoxazoles (IIIa-e).
- Sharma, T. C.,Rojindar, S.,Berge, D. D.,Kale, A. V.
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