- Preparation method of isoxazole derivative
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The invention relates to a preparation method of an isoxazole derivative, which comprises the following steps of mixing an propargyl alcohol derivative, a halogen source, an acid and a solvent, and heating to react; adding the hydroxylamine into the react
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Paragraph 0084-0089
(2019/12/02)
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- Method for converting lignin into isoxazole and aromatic nitrile
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The present invention relates to a method for obtaining isoxazole and aromatic nitrile from a lignin model and pre-oxidized birch lignin. The method is characterized in that hydroxylamine hydrochloride and a beta-O-4 model compound containing ketone in the benzyl position, which are used as reaction substrates, undergo oximation condensation Cbeta-O bond fracture under the action of magnesium andother additives to prepare the isoxazole compound, and undergo oximation rearrangement Calpha-Cbeta bond fracture the action of magnesium and other additives to prepare the fragrant nitrile compound.The method can be applied to the conversion of pre-oxidized lignin into the isoxazole and aromatic nitrile. The preparation method comprises the following steps: mixing the beta-O-4 model compound orpre-oxidized birch lignin, hydroxylamine hydrochloride and the additives in an alcohol solvent, adding the obtained mixture into a pressure-resistant container, replacing air in the container with nitrogen, sealing the container, and stirring the mixture at 120 DEG C for 8-12 h to obtain the products isoxazole and aromatic nitrile. The method realizes the obtaining of nitrogen-containing compoundssuch as isoxazole and aromatic nitrile from lignin for the first time, and the reaction process is simple and controllable, and is easy to operate.
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Paragraph 0039; 0040; 0041; 0042; 0064
(2019/07/04)
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- Polymer-supported vinyl sulfone as an efficient reagent for the synthesis of 3-monosubstituted isoxazoles
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Polystyrene-supported vinyl sulfone reagent has been developed and used for solid-phase organic synthesis of 3-monosubstituted isoxazoles by 1,3-dipolar cycloaddition reaction with nitrile oxides and subsequent cleavage from the polymer support through an
- Wu, Guo-Jian,Sheng, Shou-Ri,Li, Dan,Xu, Li-Fan,Huang, Zhen-Zhong
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p. 3034 - 3043
(2013/09/12)
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- Efficient and regioselective one-pot synthesis of 3-substituted and 3,5-disubstituted isoxazoles
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(Figure Presented) A series of 3-substituted and 3,5-disubstituted isoxazoles have been efficiently synthesized in moderate to excellent yields by the reaction of N-hydroxyl-4-toluenesulfonamide with α,β-unsaturated aldehydes/ketones. This novel strategy is associated with readily available starting materials, mild conditions, high regioselectivity, and wide scope.
- Tang, Shibing,He, Jinmei,Sun, Yongquan,He, Liuer,She, Xuegong
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supporting information; experimental part
p. 3982 - 3985
(2009/12/03)
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- Reaction of β-dimethylaminovinyl ketones with hydroxylamine: A simple and useful method for synthesis of 3- and 5-substituted isoxazoles
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(Chemical Equation Presented) The regioselective synthesis of 3- and 5-substituted-isoxazoles from the reaction of β-dimethylaminovinyl ketones [R-C(O)CH=CH-NMe2, where R = Ph, MeO-4-C6H4, F-4-C6H4, C
- Rosa, Fernanda A.,Machado, Pablo,Bonacorso, Helio G.,Zanatta, Nilo,Martins, Marcos A. P.
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p. 879 - 885
(2008/09/21)
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- Effect of the aryl group substituent in the dimerization of 3-arylisoxazoles to syn 2,6-diaryl-3,7-diazatricyclo[4.2.0.02,5]octan-4,8-diones induced by LDA
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3-Arylisoxazoles react with LDA in THF at 0 °C affording syn-2,6-diaryl-3,7-diazatricyclo[4.2.0.02,5]octan-4,8-diones (bis-azetidinones), via stereoselective dimerization of an azetinone anion intermediate. A?fragmentation reaction affording arylnitriles may compete with electronic and steric effects of the substituent present in the aryl group being pivotal in determining the outcome of this reaction. An interesting behaviour with LDA of arylnitriles arising from the fragmentation reaction of some 3-arylisoxazoles was also observed. N,N-Diisopropylaminobenzonitriles were in fact formed (plausibly via a benzyne mechanism) from 3-(4-chlorophenyl)isoxazole and 3-(2-chlorophenyl)isoxazole, whereas 3-(2-methylphenyl)isoquinolin-1-amine was isolated starting from 3-(2-methylphenyl)isoxazole and LDA.
- Di Nunno, Leonardo,Vitale, Paola,Scilimati, Antonio
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experimental part
p. 11198 - 11204
(2009/04/11)
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- Stereoselective dimerization of 3-arylisoxazoles to cage-shaped bis-β-lactams syn 2,6-diaryl-3,7-diazatricyclo[4.2.0.02,5]octan-4,8-diones induced by hindered lithium amides
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3-Arylisoxazoles react with hindered lithium amides giving syn 2,6-diaryl-3,7-diazatricyclo[4.2.0.02,5]octan-4,8-diones in good to fair yields. Stereochemistry of the so-obtained cage-shaped bis-β-lactams was assigned by X-ray diffraction analysis. Concerning the mechanism of formation of such hitherto unknown molecules, dimerization of an azetinone anion intermediate stereoselectively induced by Li+ chelation is suggested.
- Di Nunno, Leonardo,Vitale, Paola,Scilimati, Antonio,Simone, Laura,Capitelli, Francesco
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p. 12388 - 12395
(2008/03/13)
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- Substituent effects on 15N and 13C NMR chemical shifts of 3-phenylisoxazoles: A theoretical and spectroscopic study
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The synthesis and assignment of 15N and 13C NMR signals of the isoxazole ring in a series of parasubstituted 3-phenyl derivatives are reported. DFT calculations of 15N and 13C chemical shifts are presented and c
- Schofield, Mark H.,Sorel, Marie-Adele,Manalansan, Ryan J.,Richardson, David P.,Markgraf, J. Hodge
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p. 851 - 855
(2007/10/03)
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- One-Pot Synthesis of 3-Substituted Isoxazoles from Phenyl Vinylic Selenide
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Phenyl vinylic selenide was adopted for 1,3-dipolar cycloaddition to nitrile oxides and subsequent oxidation-elimination furnished 3-substituted isoxazoles with good yields in a one-pot, two-step transformation.
- Sheng, Shou-Ri,Liu, Xiao-Ling,Xu, Qu,Song, Cai-Sheng
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p. 2763 - 2764
(2007/10/03)
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- SITE SELECTIVITY IN THE REACTIONS OF 1,3-DIPOLES WITH NORBORNADIENE DERIVATIVES
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The cycloadditions of arylazides, benzonitrile oxides and diphenylnitrile imine to norbornadiene derivatives 1a-c showed varying degree of site- and stereo-selectivity.With dipolarophile 1a arylazides and benzonitrile oxides attack, preferentially, the electron-poor tetrasubstituted double bond, while in the case of 1b and 1c is the substituted double bond which enters the cycloaddition.By contrast, 2-diazopropane and C-phenyl-N-methylnitrone react with the sole tetrasubstituted double bond of 1a-c in stereo- and site-specific cycloadditions.The quantitative evaluation of the two possible reaction paths was performed by glc analysis.The compounds detected were those arising from Diels-Alder cycloreversions of the thermally labile intermediate adducts 2 and 3 (Scheme 1).The results were rationalized on the basis of a qualitative perturbation treatment which considers frontier orbital interactions only.
- Cristina, D.,Amici, M. De,Micheli, C. De,Gandolfi, R.
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p. 1349 - 1357
(2007/10/02)
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