- 2-Isoxazolines from arylcyclopropanes: I. Monoarylcyclopropanes in a reaction with nitrosyl chloride activated by sulfur(IV) oxide
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A reaction of monoarylcyclopropanes with nitrosyl chloride activated by sulfur (IV) oxide gave in good yields 5-arylisoxazolines. The reaction is of electrophilic character. A scheme of the reaction was suggested. Pleiades Publishing, Inc. 2006.
- Bondarenko,Gavrilova,Kazantseva,Tikhanushkina,Nifant'ev,Saginova,Zyk
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- Synthesis of 4,5-dihydroisoxazoles from arylcyclopropanes and nitrosyl chloride
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Arylcyclopropanes readily react with nitrosyl chloride in liquid sulfur dioxide to give the corresponding 5-aryl-4,5-dihydroisoxazoles in good yield. The reaction is most selective at -40 to -50°C; at higher temperature, the contribution of side processes
- Bondarenko,Gavrilova,Saginova,Zyk
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- SIMPLE IN SITU PREPARATION OF FULMINIC ACID
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Fulminic acid, generated in situ by hydrolysis of trimethylsilanecarbonitrile oxide, is employed in cycloaddition reactions.
- Sarlo, Francesco De,Brandi, Alberto,Guarna, Antonio,Goti, Andrea,Corezzi, Silvia
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- Study of the Features of the Reaction of Arylcyclopropanes with Nitrozonium Ethyl Sulfate or Nitrozonium Tetrafluoroborate
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Abstract: The reactions of diaryl-, aryl-, and alkyl–arylcyclopropanes with ethyl nitrite in the presence of sulfur trioxide and sulfur trioxide dioxane complex, as well as the reactions of 1-alkyl-2-arylcyclopropanes with NOBF4 were studied. It was found that the attack of the nitrosonium cation, accompanied by the formation of a benzyl carbocation, leads to the formation of isoxazolines. The introduction of bulky alkyl substituents into the cyclopropane ring changes the regioselectivity of nitrosation, favoring the attack of the electrophilic particle on the benzyl position and leading to the competitive formation of an alkyl carbocation. Depending on the structure of the alkyl substituent, both products of intramolecular heterocyclization accompanied by skeletal rearrangements and products formed with the participation of an external nucleophile are formed.
- Bondarenko, O. B.,Gavrilova, A. Yu.,Solodovnikova, T. A.,Tikhanushkina, V. N.,Zyk, N. V.
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p. 753 - 762
(2020/07/03)
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- Biocatalytic asymmetric ring-opening of dihydroisoxazoles: a cyanide-free route to complementary enantiomers of β-hydroxy nitriles from olefins
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By combination of the cyanide-free synthesis of chiral nitriles and the Kemp elimination reaction catalyzed by aldoxime dehydratases, we herein report a new application of aldoxime dehydratase in the asymmetric ring-opening of 5-sub-4,5-dihydroisoxazoles
- Asano, Yasuhisa,Zheng, Daijun
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supporting information
p. 4930 - 4936
(2020/08/25)
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- Isomerization of 3-unsubstituted 4,5-dihydroisoxazoles over alumina. A new synthesis of β-hydroxy nitriles
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3-Unsubstituted 4,5-dihydroisoxazoles obtained by nitrosation of arylcyclopropanes are capable of undergoing efficient isomerization into 3-aryl-3-hydroxypropanenitriles during chromatography on alumina.
- Mochalov,Fedotov,Trofimova,Gazzaeva,Zefirov
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p. 397 - 403
(2016/06/13)
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- New regiospecific catalytic approaches to 4,5-dihydroisoxazoles and 2,5-dihydroisoxazoles from o-propargylic hydroxylamines
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Unprotected O-propargylic hydroxylamines undergo generally essentially quantitative cyclisations when exposed briefly to silver nitrate adsorbed onto silica gel to give 4,5-dihydroisox-azoles [2-isoxazolines], while N-protected derivatives give the corres
- Knight, David W.,Proctor, Anthony J.,Clough, John M.
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scheme or table
p. 628 - 632
(2010/09/18)
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- The first synthesis of nitro-substituted cyclopropanes and spiropentanes via oxidation of the corresponding amino derivatives
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A novel approach to nitro-substituted cyclopropanes and spiropentanes via oxidation of the corresponding amines with dimethyldioxirane is reported. The method is used successfully for the preparation of a series of nitrocyclopropanes as well as for the first synthesis of 1,4-dinitrospiro[2.2]pentane.
- Volkova, Yuliya A.,Ivanova, Olga A.,Budynina, Ekaterina M.,Revunov, Eugene V.,Averina, Elena B.
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scheme or table
p. 2793 - 2796
(2009/09/28)
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- The preparation of 2-isoxazolines from O-propargylic hydroxylamines via a tandem rearrangement-cyclisation reaction
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A method for the conversion of O-propargylic hydroxylamines into 2-isoxazolines in 60-84% yield is described. For 3-alkylpropargyl or 3-arylpropargyl hydroxylamines this was achieved by heating a methanolic solution of the hydrochloride salt in the presen
- Pennicott, Lewis,Lindell, Stephen
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p. 463 - 465
(2007/10/03)
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- Oxidation of alkylarenes by nitrate catalyzed by polyoxophosphomolybdates: Synthetic applications and mechanistic insights
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Alkylarenes were catalytically and selectively oxidized to the corresponding benzylic acetates and carbonyl products by nitrate salts in acetic acid in the presence of Keggin type molybdenum-based heteropolyacids, H3+xPVxMo12-xO40 (x = 0-2). H 5PV2Mo10O40 was especially effective. For methylarenes there was no over-oxidation to the carboxylic acid contrary to what was observed for nitric acid as oxidant. The conversion to the aldehyde/ketone could be increased by the addition of water to the reaction mixture. As evidenced by IR and 15N NMR spectroscopy, initially the nitrate salt reacted with H5PV2Mo10O 40 to yield a NVO2+[H 4PV2Mo10O40] intermediate. In an electron-transfer reaction, the proposed NVO2 +[H4PV2Mo10O40] complex reacts with the alkylarene substrate to yield a radical-cation-based donor-acceptor intermediate, NIVO2[H4PV 2Mo10O40]-ArCH2R+.. Concurrent proton transfer yields an alkylarene radical, ArCHR., and NO2. Alternatively, it is possible that the NVO 2+[H4PV2Mo10O 40] complex abstracts a hydrogen atom from alkylarene substrate to directly yield ArCHR. and NO2. The electron transfer-proton transfer and hydrogen abstraction scenarios are supported by the correlation of the reaction rate with the ionization potential and the bond dissociation energy at the benzylic positions of the alkylarene, respectively, the high kinetic isotope effect determined for substrates deuterated at the benzylic position, and the reaction order in the catalyst. Product selectivity in the oxidation of phenylcyclopropane tends to support the electron transfer-proton transfer pathway. The ArCHR. and NO2 radical species undergo heterocoupling to yield a benzylic nitrite, which undergoes hydrolysis or acetolysis and subsequent reactions to yield benzylic acetates and corresponding aldehydes or ketones as final products.
- Khenkin, Alexander M.,Neumann, Ronny
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p. 6356 - 6362
(2007/10/03)
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- The Addition of Diallylzinc to 5-Substituted 4,5-Dihydroisoxazoles
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The addition of diallyl zinc to range of 5-aryl-4,5-dihydroisoxazoles, occurs with a diastereoselectivity of between 6.9:1 and 3.6:1. The major product is the trans isomer as demonstrated by an X-ray crystal structure on the phenyl thiourea derivative of
- Castro, Francisco J. Freire,Vila, Manuel M.,Jenkins, Paul R.,Sharma, Madan L.,Tustin, Gary,et al.
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p. 798 - 800
(2007/10/03)
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- PARA-ALKYL-SUBSTITUTED PHENYLCYCLOPROPANES IN REACTION WITH DINITROGEN TETROXIDE
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The reaction of para-alkyl-substituted phenylcyclopropanes with dinitrogen tetroxide was studied.In solvents with various polarities at -30 deg C dinitrogen tetroxide only reacts with the three-carbon ring.Here the initially formed adducts are only stable at low temperatures; with increase in temperature they are converted into p-alkylcinnamaldehydes and 5-(p-alkylphenyl)isoxazolines.
- Smirnova, M. M.,Geiderikh, A. V.,Mochalov, S. S.,Shabarov, Yu. S.
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p. 1070 - 1075
(2007/10/02)
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- THE CHEMISTRY OF FULMINIC ACID REVISED
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The availability of a new synthesis of fulminic acid by hydrolysis of trimethylsilanecarbonitrile oxide allowed a reinvestigation of the chemistry of the title compound.Thus, cycloadditions to olefinic and acetylenic dipolarophiles are improved with respect to previous results and the oligomerisation is proved to occur via the reactive species hydroxyiminoacetonitrile oxide 7 and hydroxyiminomethyl-hydroxyimino-acetonitrile oxide 8.The Z-configuration, found for the oxime groups in these intermediates, is maintained in their derivatives, under kinetic control.
- Sarlo, Francesco De,Guarna, Antonio,Brandi, Alberto,Goti, Andrea
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p. 5181 - 5186
(2007/10/02)
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