- Nitration of Alkenes and Oxiranes with Nitrogen(IV) Oxide in Liquid and Supercritical Carbon Dioxide Media
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Abstract: For the first time the reactions of radical nitration of alkenes and oxiranes with nitrogen dioxide in the liquid and supercritical carbon dioxide (sc-CO2) media were carried out. Using octene-1, styrene, and their derivatives as exam
- Ivanov, R. E.,Zharkov, M. N.,Zlotin, S. G.
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p. 209 - 212
(2022/02/22)
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- Unprecedented Mechanism of an Organocatalytic Route to Conjugated Enynes with a Junction to Cyclic Nitronates
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Conjugated enynes as well as cyclic nitronates are crucial building blocks for numerous natural products and pharmaceuticals. However, so far, no common and metal-free synthetic route to both conjugated enynes and cyclic nitronates has been reported. Herein, in situ NMR, labelling studies and theoretical calculations were combined to investigate the mechanism of the unusual triple bond formation towards conjugated enynes. Starting from nitroalkene dimers, first an isoxazolidine-2,5-diol derivative is formed as central intermediate. From this, enynes were generated by a combination of oxidation, dehydration, and retro 1,3-dipolar cycloaddition, whereas for nitronates a base induced intramolecular reorganization is proposed. While the product distribution could be controlled and high yields of nitronate were achieved, only medium to good yields for enynes were obtained due to polymerization losses. Nevertheless, we hope that these mechanistic investigations may provide a basis for further developments of organocatalytic or metal-free preparations of conjugated enynes and nitronates.
- Streitferdt, Verena,Haindl, Michael H.,Hioe, Johnny,Morana, Fabio,Renzi, Polyssena,von Rekowski, Felicitas,Zimmermann, Alexander,Nardi, Martina,Zeitler, Kirsten,Gschwind, Ruth M.
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supporting information
p. 328 - 337
(2018/11/23)
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- Enantio- & chemo-selective preparation of enantiomerically enriched aliphatic nitro alcohols using Candida parapsilosis ATCC 7330
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Enantiomerically pure β- and γ-nitro alcohols were prepared from their respective nitro ketones by asymmetric reduction mediated by the biocatalyst, Candida parapsilosis ATCC 7330 under optimized reaction conditions (ee up to >99%; yields up to 76%). This
- Venkataraman, Sowmyalakshmi,Chadha, Anju
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p. 73807 - 73813
(2015/09/15)
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- Henry reaction in aqueous media at neutral pH
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An efficient method for the synthesis of β-nitro alcohols from nitro alkanes and aldehydes in aqueous phosphate buffer under neutral pH conditions at room temperature is reported. In the case of higher nitro alkanes, the reaction showed very good diastereoselectivity to give syn β-nitro alcohols in preference to their anti products. Copyright
- Bora, Pranjal P.,Bez, Ghanashyam
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p. 2922 - 2929
(2013/06/27)
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- Copper complex of aminoisoborneol schiff base Cu2(SBAIB-d) 2: An efficient catalyst for direct catalytic asymmetric nitroaldol (henry) reaction
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A new bifunctional copper complex of the aminoisoborneol Schiff base - Cu2(SBAIB-d)2 - has been developed for the effective direct catalytic asymmetric Henry reaction. One mol% of this catalyst produces the expected Henry products in high yields (up to 99%) with excellent enantioselectivities (up to 98% ee). The utility of the present catalyst was also extended to the Henry reaction with nitroethane and 1-nitropropane that furnished the corresponding products in moderate to high yields (up to 99%) with moderate to high enantioselectivities of syn (up to 98% ee) and anti (up to 98% ee) diastereomers. The highlights of this catalytic system are easy manipulation, air and moisture tolerance, the need for 1 mol% of an easily synthesizable catalyst and the high enantioselectivities achieved for a wide range of substrates. Copyright
- Boobalan, Ramalingam,Lee, Gene-Hsian,Chen, Chinpiao
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supporting information
p. 2511 - 2520
(2012/11/07)
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- Dual-reagent organocatalysis with a phosphine and electron-deficient alkene: application to the Henry reaction
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Triphenylphosphine in combination with methyl acrylate was found to be able to catalyze the Henry (nitroaldol) reaction of various aldehydes and α-keto esters to give the corresponding β-nitroalkanols in good to excellent yields, and a catalytic cycle involving a zwitterionic phosphine-alkene adduct was proposed for this dual-reagent organocatalysis according to the deuterium-labeling experiments with CD3NO2.
- Wang, Xiu,Fang, Fan,Zhao, Chen,Tian, Shi-Kai
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scheme or table
p. 6442 - 6444
(2009/04/06)
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- Rapid microwave-assisted Henry reaction in solvent-free processes
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The solvent-free Henry reactions of nitromethane with a series of carbonyl compounds were studied under microwave irradiation. By using different bases and Lewis acids, the solvent-free nitroaldol reaction of aldehydes were realized under microwave condition, affording the corresponding adducts with high yields. Particularly, aliphatic ketones, which were hardly carried out this reaction, could be the reaction substrates in the nitroaldol reactions by employment of 1,4-diazabicyclo[2.2.2]octane (DABCO) under a similar conditions, giving the corresponding adducts with moderate to good yields. Georg Thieme Verlag Stuttgart.
- Gan, Changsheng,Chen, Xing,Lai, Guoyin,Wang, Zhiyong
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p. 387 - 390
(2007/10/03)
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- Phosphine-catalyzed nitroaldol reactions
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Trialkyl phosphines and electron-rich triaryl phosphines are excellent catalysts for the nitroaldol (Henry) reaction. Aryl and alkyl aldehydes participate well in the reaction with nitromethane providing good yields of product. Care should be exercised in the use of phosphine-metal complexes as catalysts for the nitroaldol reaction, as the phosphine can alone function as the catalyst.
- Weeden, Jason A.,Chisholm, John D.
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p. 9313 - 9316
(2007/10/03)
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- Method for manufacturing isoxazole derivative or dihydroisoxazole derivative
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There is provided with a method for manufacturing an isoxazole derivative at a high yield and without discharging waste products, and a novel isoxazole derivative. An isoxazole derivative expressed by Formula (8) is produced by reacting a 1-alkyne compoun
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Page/Page column 12-13
(2008/06/13)
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- A convenient and efficient one-pot synthesis of 3-acylisoxazoles using iron(III) salts
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3-Acylisoxazoles were synthesized by the reaction of alkenes or alkynes with ketones (acetone or acetophenone), as both a reagent and the solvent, by three methods: iron(III) nitrate under reflux, iron(III) salt-nitrogen dioxide (NO2) at room temperature,
- Itoh, Ken-Ichi,Sakamaki, Hiroshi,Nakazato, Noriko,Horiuchi, Atsuo,Horn, Ernst,Horiuchi, C. Akira
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p. 3541 - 3548
(2007/10/03)
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- Tin(II)chloride mediated addition reaction of bromonitromethane to aldehydes
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Bromonitromethane adds to aliphatic aldehydes in the presence of tin(II) chloride to yield β-nitro alcohols via a Reformatsky-type reaction in high yields, while aromatic aldehydes give low yields. The products were characterized by IR, NMR, and mass spectroscopy and by elemental analysis.
- Mahasneh, Ali S.
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p. 416 - 418
(2007/10/03)
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- Hydrotalcite catalysis in ionic liquid medium: A recyclable reaction system for heterogeneous Knoevenagel and nitroaldol condensation
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Knoevenagel condensation proceeds efficiently in recyclable [bmim]PF 6 and [bmim]BF4 without any catalyst, and hydrotalcites in ionic liquid serve as a safe and recyclable reaction system for both Knoevenagel as well as nitroaldol condensations.
- Khan, Faiz Ahmed,Dash, Jyotirmayee,Satapathy, Rashmirekha,Upadhyay, Sarasij K.
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p. 3055 - 3058
(2007/10/03)
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- Ionic liquid catalyzed Henry reactions
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The 1,1,3,3-tetramethyl guanidine (TMG)-based ionic liquid was used as a recyclable catalyst for Henry reactions to produce 2-nitroalcohols. Good yields were obtained even after 15 reactions.
- Jiang, Tao,Gao, Haixiang,Han, Buxing,Zhao, Guoying,Chang, Yanhong,Wu, Weize,Gao, Liang,Yang, Guanying
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p. 2699 - 2701
(2007/10/03)
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- Formation of isoxazole derivatives via nitrile oxide using ammonium cerium nitrate (CAN): A novel one-pot synthesis of 3-acetyl- and 3-benzoylisoxazole derivatives
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The reactions of alkenes and alkynes with ammonium cerium(IV) nitrate ((NH4)2Ce(NO3)6, CAN(IV)) in acetone under reflux gave the corresponding 3-acetyl-4,5-dihydroisoxazole and 3-acetylisoxazole derivatives. In the case of acetophenone, 3-benzoyl-4,5- dihydroisoxazole and 3-benzoylisoxazole derivatives were obtained. Reaction of acetone with CAN(IV) afforded the corresponding furoxan (3,4-diacetyl-1,2,5- oxadiazole 2-oxide) as the dimer of nitrile oxide. Moreover, it was found that yields of isoxazole derivatives were improved using ammonium cerium(III) nitrate tetrahydrate ((NH4)2Ce(NO3) 5·4H2O, CAN(III))-formic acid. The reaction mechanisms based on nitration and formation of nitrile oxide mediated by CAN(IV) or CAN(III) from acetone or acetophenone are also proposed.
- Itoh, Ken-Ichi,Horiuchi, C. Akira
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p. 1671 - 1681
(2007/10/03)
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- Activation of nitroaldol reactions by diethylzinc and amino alcohols or diamines as promoters
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Henry reactions of nitroalkanes can be initiated with diethylzinc in the presence of catalytic amounts of 1,2-aminoethanol or 1,2-diaminoethane.
- Klein, Günter,Pandiaraju, Subramaniam,Reiser, Oliver
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p. 7503 - 7506
(2007/10/03)
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- P(RNCH2CH2)3N: An Efficient Promoter for the Nitroaldol (Henry) Reaction
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The use of catalytic amounts of the proazaphosphatranes P(MeNCH2CH2)3N, P(i-PrNCH2CH2)3N and P(HNCH2CH2)(i-PrNCH2CH2) 2N as nonionic bases in the reaction of nitroalkanes with carbonyl compounds is reported. The reaction proceeds at room temperature in the presence of 2.2 equiv of magnesium sulfate to produce the corresponding β-nitroalkanols in generally superior yields. Aldehydes react quantitatively in 5-60 min, whereas ketones require up to 3 h to react with nitromethane and up to 7 h for the reaction of ketones with higher nitroalkanes.
- Kisanga, Philip B.,Verkade, John G.
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p. 4298 - 4303
(2007/10/03)
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- Nitroaldol (Henry) reaction catalyzed by amberlyst A-21 as a far superior heterogeneous catalyst
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β-Nitroalcohols can be efficiently obtained with the help of Amberlyst A-21, as heterogeneous basic catalyst, with or without solvent. This method is far superior to the heterogeneous catalysts previously reported for the nitroaldol (Henry) reaction, in f
- Ballini, Roberto,Bosica, Giovanna,Forconi, Paola
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p. 1677 - 1684
(2007/10/03)
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