- Biocatalytic Aza-Michael Addition of Aromatic Amines to Enone Using α-Amylase in Water
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The Michael addition of amines with enones for synthesizing β-amino carbonyls constitutes a valuable transformation in organic chemistry. While various catalyst have been made available for catalyzing the Michael addition of aromatic amines to enones but
- Dutt, Sunil,Goel, Vanshita,Garg, Neha,Choudhury, Diptiman,Mallick, Dibyendu,Tyagi, Vikas
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supporting information
p. 858 - 866
(2020/01/03)
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- Method for generating beta-amino ketone compounds through iodine catalysis
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The invention discloses a method for generating beta-amino ketone compounds by catalyzing 4-hydroxy-2-butanone to react with aromatic amine through iodine. The method comprises the following steps: taking 4-hydroxy-2-butanone and different aromatic amines as reaction substrates, taking iodine as a catalyst, and dimethyl sulfoxide or N,N-dimethyl formamide as a solvent, and reacting at room temperature in a nitrogen atmosphere to obtain the beta-amino ketone compounds, wherein other byproducts are undetected. By adopting the preparation method disclosed by the invention, the beta-amino ketone compounds can be generated by catalyzing 4-hydroxy-2-butanoe to react with aromatic amine through the iodine at room temperature for the first time.
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Paragraph 0024-0025; 0026-0028; 0075-0076; 0082; 0086-0087
(2019/02/26)
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- Iodine-catalyzed coupling of β-hydroxyketones with aromatic amines to form β-aminoketones and Benzo[h]quinolones
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An iodine-catalyzed coupling of β-hydroxyketones with aromatic amines to yield β-aminoketones and benzo[h]quinolones had been developed. Noble metallic catalysts, oxidants, α β-unsaturated ketone intermediates and aza-Michael addition were not involved in this coupling reaction which made it unique when compared to other reactions reported in literature. Inexpensive iodine catalyst, easy accessible raw materials, mild reaction conditions, good functional group tolerance and excellent selectivity made this coupling reaction be a practical method. This reaction can also be scaled up.
- Miao, Changqing,Jiang, Liya,Ren, Lanhui,Xue, Qingxia,Yan, Fang,Shi, Weiwei,Li, Xinjian,Sheng, Jiwen,Kai, Shuangshuang
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p. 2215 - 2228
(2019/02/27)
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- Method for catalyzing N-alkylation reaction by TEMPO and TBN
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The invention discloses a method for catalyzing N-alkylation reaction of aniline and 4-hydroxy-2-butanone by TEMPO and TBN. 4-hydroxy-2-butanone and different anilines are used as the reaction substrate, TEMPO (2,2,6,6-tetramethylpiperidine oxide) is used as catalyst, TBN (tert-butyl nitrite) is used as cocatalyst, dimethyl sulfoxide or N,N-dimethylformamide or toluene is used as solvent, N-alkylation product is obtained in nitrogen atmosphere at room temperature, no other by-products are detected. The preparation method of the invention uses TEMPO and TBN to catalyze aniline compounds and 4-hydroxy-2-butanone to perform N-alkylation reaction.
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Paragraph 0023-0031; 0078-0094
(2019/11/20)
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- TBN-Catalyzed Dehydrative N-Alkylation of Anilines with 4-Hydroxybutan-2-one
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Until now, the substitution of alcohols by N-nucleophiles via TBN-catalyzed dehydrogenation was not known. Herein, we reported a TBN catalyzed dehydrative N-alkylation of anilines with 4-hydroxybutan-2-one in the presence of TEMPO, which was different from the TEMPO/TBN catalyzed oxidation reactions. A range of anilines reacted successfully with 4-hydroxybutan-2-one to generate the N-monoalkylation products in good yields. Mechanistic studies revealed that this reaction most possibly proceeded through aza-Michael addition. Water was the only by-product, making it more environmentally friendly. The gram-scale reactions verified the synthetic practicality of this protocol.
- Cheng, Wenchen,Deng, Shue,Jiang, Liya,Ren, Lanhui,Wang, Zicheng,Zhang, Jian,Song, Weiguo
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supporting information
p. 7372 - 7377
(2019/11/28)
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- TiCl2(OTf)-SiO2: A solid stable lewis acid catalyst for Michael addition of α-Aminophosphonates, Amines, Indoles and Pyrrole
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TiCl2(OTf)-SiO2 is simply prepared by immobilization of TiCl3(OTf) on silica gel surface and introduced as a non-hygroscopic Lewis acid catalyst for C-N and C-C bond formation via Michael addition reaction. A variety of structurally diverse nitrogen nucleophiles including α-aminophosphonates, aliphatic and aromatic amines and imidazole were evaluated as Michael donors. Friedel–Crafts alkylation of indoles and pyrrole was also investigated through Michael addition reaction in the presence of TiCl2(OTf)-SiO2 as a catalyst. The reactions were conducted at room temperature or 60 °C under solvent-free conditions and the desired Michael adducts were obtained in high to excellent yields.
- Firouzabadi, Habib,Iranpoor, Naser,Farahi, Soghra
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p. 317 - 323
(2018/02/06)
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- Palladium-catalyzed aerobic oxidative coupling of allylic alcohols with anilines in the synthesis of nitrogen heterocycles
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We report herein an unprecedented and expedient Pd-catalyzed oxidative coupling of allyl alcohols with anilines to afford β-amino ketones which are converted into substituted quinolines in a one-pot fashion. The exclusive preference for N-alkylation over N-allylation makes this approach unique when compared to those reported in literature. Detailed mechanistic investigations reveal that the conjugate addition pathway was the predominant one over the allylic amination pathway. The notable aspects of the present approach are the use of readily available, bench-stable allyl alcohols and molecular oxygen as the terminal oxidant, in the process dispensing the need for unstable and costly enones. Further, we explored the synthetic utility of β-amino ketones through an intramolecular α-arylation methodology and a one-pot domino annulation, thereby providing rapid access to indolines and quinolines.
- Kumar, Gangam Srikanth,Singh, Diksha,Kumar, Manish,Kapur, Manmohan
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p. 3941 - 3951
(2018/04/14)
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- Cobalt-Porphyrin-Catalyzed Intramolecular Buchner Reaction and Arene Cyclopropanation of In Situ Generated Alkyl Diazomethanes
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Cobalt(II)-porphyrin catalyzed intramolecular Buchner reaction and arene cyclopropanation of alkyl diazomethanes generated in situ from N-tosylhydrazones gave a range of bicyclic cycloheptatriene fused pyrrolidines and tetracyclic cyclopropane fused pyrro
- Wang, Haixu,Zhou, Cong-Ying,Che, Chi-Ming
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supporting information
p. 2253 - 2258
(2017/07/07)
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- Palladium-catalyzed oxidative amination of homoallylic alcohols: Sequentially installing carbonyl and amino groups along an alkyl chain
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A novel Pd-catalyzed intermolecular cascade oxidative amination of homoallylic alcohols to yield β-amino ketones has been developed by using TBHP as the terminal oxidant. The synthetic utility of the reaction can be performed by installing the carbonyl an
- Ouyang, Lu,Huang, Jiuzhong,Li, Jianxiao,Qi, Chaorong,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 10422 - 10425
(2017/09/25)
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- A photoredox catalyzed radical-radical coupling reaction: Facile access to multi-substituted nitrogen heterocycles
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Visible light induced photoredox catalysis is an efficient method for radical activation. Herein, we report the photoredox catalysis involving an intramolecular radical-radical coupling reaction that proceeds through a biradical intermediate. This protocol represents a new synthetic route to construct multi-substituted N-heterocycles. Four, five and six-membered N-heterocyclic structures with a quaternary carbon center are accessible under mild conditions.
- Li, Weipeng,Duan, Yingqian,Zhang, Muliang,Cheng, Jian,Zhu, Chengjian
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supporting information
p. 7596 - 7599
(2016/07/06)
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- Understanding α,β-unsaturated imine formation from amine additions to α,β-unsaturated aldehydes and ketones: An analytical and theoretical investigation
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A combination of in situ IR spectroscopy (ReactIR) and DFT calculations have been used to understand what factors govern the selectivity in the addition of primary amines to α,β-unsaturated aldehydes and ketones, i.e., 1,2- versus 1,4-addition. It has been found that the 1,2-addition products (α,β-unsaturated imines following addition and elimination) usually predominate for most systems. However, exceptions, such as methyl vinyl ketone, selectively give 1,4-addition products. This has been rationalized by DFT calculations that show that major conformational effects are involved, controlled mainly by steric effects of carbonyl substituents, resulting in a model that provides simple and predictable preparation of α,β- unsaturated imines for in situ utilization in synthesis.
- Calow, Adam D. J.,Carbó, Jorge J.,Cid, Jessica,Fernández, Elena,Whiting, Andrew
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supporting information
p. 5163 - 5172
(2014/06/23)
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- Amphiphilic methyleneamino synthon through organic dye catalyzed- decarboxylative aminoalkylation
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The utilization of a photo-induced synthon generated from N-phenyl glycine by an organic dye and visible light irradiation is disclosed. The intermediate could be coupled with either a radical or a nucleophile in a simple operation to afford several natural product-like compounds.
- Chen, Li,Chao, Chin Sheng,Pan, Yuanhang,Dong, Sheng,Teo, Yew Chin,Wang, Jian,Tan, Choon-Hong
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supporting information
p. 5922 - 5925
(2013/09/12)
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- Dolomite (CaMg(CO3)2) as a recyclable natural catalyst in Henry, Knoevenagel, and Michael reactions
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Iranian dolomite (CaMg(CO3)2) which consists of double-layered carbonates with Ca2+ and Mg2+ ions was utilized as a heterogeneous base catalyst in the CC, CN, and CS bond forming reactions via the Henry, Knoevenagel, aza-Michael, and thia-Michael transformations under mild conditions in water. Iranian dolomite has been characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer Emmett Teller (BET) and XRF chemical analysis, while its basic strength was evaluated by following the Hammett indicators procedure. This water-insoluble natural catalyst demonstrated high activity and was reusable.
- Tamaddon, Fatemeh,Tayefi, Mohammad,Hosseini, Elaheh,Zare, Elham
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- O-benzenedisulfonimide as a reusable brnsted acid catalyst for hetero-michael reactions
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The hetero-Michael reactions among various oxygen, sulfur, and nitrogen nucleophiles and ,-unsaturated compounds were carried out in the presence of catalytic amounts of o-benzenedisulfonimide as Brnsted acid organocatalyst. The reaction conditions were very mild, and the yields of target products were good. The catalyst was easily recovered and purified, ready to be used in further reactions. This ability grants economic and ecological advantages. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
- Barbero, Margherita,Cadamuro, Silvano,Dughera, Stefano
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p. 758 - 767
(2013/01/15)
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- Boric acid/glycerol as an efficient catalyst for synthesis of thiomorpholine 1,1-dioxide by double michael addition reaction in water
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Thiomorpholine 1,1-dioxides were prepared with double Michael addition reaction of aromatic amines to divinyl sulfone catalyzed by boric acid/glycerol in water. This catalyst system was also used for the Michael addition reaction of aromatic amines to electron-deficient alkenes. The reaction is simple and green and gives good to excellent yields.
- Halimehjnai, Azim Ziyaei,Hosseyni, Seyedmorteza,Gholami, Hadi,Hashemi, Mohammed M.
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p. 191 - 197,7
(2020/09/02)
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- Anodic generation of a zirconium catalyst for Ferrier rearrangement and hetero Michael addition
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An efficient catalyst for Ferrier rearrangement and hetero-Michael addition was successfully generated from a sacrificial zirconium anode into media containing reactants for these reactions. Thus, the catalyst generated, successfully promoted the allylic
- Stevanovic, Dragana,Pejovic, Anka,Damljanovic, Ivan,Vukic evic, Rastko D.,VukiC evic, Mirjana,Bogdanovic, Goran A.
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p. 6257 - 6260,4
(2012/12/11)
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- Lithium tetrafluoroborate catalyzed highly efficient inter- and intramolecular aza-Michael addition with aromatic amines
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Lithium tetrafluoroborate has been demonstrated for the first time to be an efficient catalyst in intermolecular aza-Michael addition aromatic amines to electron deficient alkenes. Suitability of the same catalyst in intramolecular aza-Michael addition leading 2-aryl-2,3-dihydroquinolin-4(1H) ones has also been described.
- Lad,Kulkarni,Desai,Wadgaonkar
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experimental part
p. 1059 - 1064
(2012/03/11)
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- Aza-Michael reactions in water using functionalized ionic liquids as the recyclable catalysts
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Some recyclable SO3H-functionalized ionic liquids have been used as catalysts in water for the aza-Michael reactions of amines with α,β-unsaturated compounds to produce β-amino compounds. High yields of the products, short reaction times, mild reaction conditions, simple experimental procedure, reusable catalysts and no obvious loss of the catalytic activity make this protocol a contribution to organic chemistry.
- Liu,Lu,Gu,Lu
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experimental part
p. 775 - 781
(2012/06/18)
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- Green, efficient and practical Michael addition of arylamines to α,β-unsaturated ketones
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The aza-Michael addition of aromatic amines to α,β-unsaturated ketones was carried out effectively at room temperature in good to excellent yields without any catalyst or solvent. It was significant that part of adducts could be collected in almost quanti
- Jiang, Ran,Li, Dan-Hua,Jiang, Jing,Xu, Xiao-Ping,Chen, Tao,Ji, Shun-Jun
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supporting information; experimental part
p. 3631 - 3637
(2011/06/21)
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- N-heterocyclic carbene-catalyzed aza-michael addition
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Aza-Michael addition of amines, including aromatic and aliphatic amines, with α, β-unsaturated ketones was realized employing N-Heterocyclic Carbene (NHC) as organocatalyst, yielding β-amino ketones with up to 98% yield.
- Kang, Qiang,Zhang, Yugen
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experimental part
p. 6715 - 6720
(2011/11/06)
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- Squaric acid as an impressive organocatalyst for Michael addition in water
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A simple, green, and environmentally benign protocol for squaric acid (5 mg) catalyst conjugate addition of aromatic amines and thiols to unsaturated carbonyl compounds in water in good to excellent yields is developed. The advantages of low sensitivity toward moisture and oxygen, high tolerance of different functional groups, green reaction media and efficient recyclability make this organocatalyst suitable for both laboratory and industrial scale synthesis of β-substituted carbonyls under very mild conditions.
- Azizi, Najmadin,Saki, Elham,Edrisi, Mahtab
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experimental part
p. 973 - 977
(2012/05/20)
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- Ruthenium-catalysed synthesis of 2- and 3-substituted quinolines from anilines and 1,3-diols
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A straightforward synthesis of substituted quinolines is described by cyclocondensation of anilines with 1,3-diols. The reaction proceeds in mesitylene solution with catalytic amounts of RuCl3·xH 2O, PBu3 and MgBr2·OEt2. The transformation does not require any stoichiometric additives and only produces water and dihydrogen as byproducts. Anilines containing methyl, methoxy and chloro substituents as well as naphthylamines were shown to participate in the heterocyclisation. In the 1,3-diol a substituent was allowed in the 1- or the 2-position giving rise to 2- and 3-substituted quinolines, respectively. The best results were obtained with 2-alkyl substituted 1,3-diols to afford 3-alkylquinolines. The mechanism is believed to involve dehydrogenation of the 1,3-diol to the 3-hydroxyaldehyde which eliminates water to the corresponding α,β-unsaturated aldehyde. The latter then reacts with anilines in a similar fashion as observed in the Doebner-von Miller quinoline synthesis.
- Monrad, Rune Nygaard,Madsen, Robert
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scheme or table
p. 610 - 615
(2011/02/28)
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- "On-water" conjugate additions of anilines
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The conjugate addition of anilines onto unsaturated ketones, esters and N-acylpyrroles was investigated. Based on a recently proposed explanation for the phenomenon of on-water catalysis, operationally simple and mild reaction conditions for effecting these addition reactions have been developed. The success of these additions provides further support for the acid-catalysed nature of on-water chemistry.
- Phippen, Christopher B. W.,Beattie, James K.,McErlean, Christopher S. P.
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supporting information; experimental part
p. 8234 - 8236
(2010/12/20)
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- Task-specific ionic-liquid-catalyzed efficient synthesis of indole derivatives under solvent-free conditions
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A sulfonic-acid-functionalized ionic liquid is used as a Bronsted acid catalyst for the efficient synthesis of indole derivatives in good-to-high yields at room temperature under solvent-free conditions. The catalyst can be reused for ten consecutive runs without significant loss of activity.
- Das, Sudarshan,Rahman, Matiur,Kundu, Dhiman,Majee, Adinath,Hajra, Alakananda
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scheme or table
p. 150 - 154
(2010/04/03)
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- Functionalized ionic liquid promoted aza-michael addition of aromatic amines
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A functionalized ionic liquid, 3-(N,N-dimethyldodecylammonium) propanesulfonic acid hydrogen sulphate ([DDPA][HSO4]) has been used as catalyst for the aza-Michael reactions of aromatic amines with α,β-unsaturated compounds at room temperature to produce β-amino compounds in good yields. The catalyst can be reused for several times without obvious loss of the catalytic activity.
- Liu, Xiao-Bing,Lu, Ming,Lu, Ting-Ting,Gu, Guo-Liang
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experimental part
p. 1221 - 1226
(2011/10/02)
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- Silicon tetrachloride catalyzed aza-michael addition of amines to conjugated alkenes under solvent-free conditions
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The efficient and very simple conjugate addition of aromatic and aliphatic amines to α,β-unsaturated carbonyl compounds under solvent-free conditions in the presence of catalytic amount of silicon tetrachloride is reported. The reaction of aryl and alkyl amines with different Michael acceptors gave the corresponding Michael adducts with simple catalyst and good to excellent yields. Georg Thieme Verlag Stuttgart New York.
- Azizi, Najmedin,Baghi, Roya,Ghafuri, Hossein,Bolourtchian, Mohammad,Hashemi, Mohammad
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experimental part
p. 379 - 382
(2010/04/03)
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- Zirconium tetrakis(dodecylsulfate) as an efficient and recyclable lewis acid-surfactant-combined catalyzed C-C and C-N bond forming under mild and environmentally benign conditions
-
A green catalytic method for C-C and C-N bond forming via Michael addition of aromatic amines and indoles to electron-deficient olefins using Zirconium tetrakis(dodecylsulfate) in water under mild conditions with high yields and selectivity has been developed. The reusability of the catalyst has been successfully examined without any noticeable loss of its catalytic activity.
- Jafarpour, Maasoumeh,Rezaeifard, Abdolreza,Aliabadi, Marzieh
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scheme or table
p. 94 - 99
(2010/04/23)
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- Solvent-promoted and -controlled Aza-Michael reaction with aromatic amines
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(Chemical Equation Presented) 1,4-Addition of anilines onto Michael acceptors proceeds easily in specific polar protic solvents, without any promoting agent. According to the solvent and to the electrophile, the selectivity of the reaction can be finely tuned. With methyl acrylate as electrophile, only monoaddition takes place in water, while the diadduct is yielded in hexafluoroisopropyl alcohol (HFIP). The use of methyl vinyl ketone as a partner affords the monoadduct in water, the diadduct in trifluoroethanol (TFE), and the quinoline in HFIP.
- De, Kavita,Legros, Julien,Crousse, Benoit,Bonnet-Delpon, Daniele
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experimental part
p. 6260 - 6265
(2009/12/06)
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- Highly efficient Michael addition reaction of amines catalyzed by silica-supported aluminum chloride
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Aliphatic and aromatic amines undergo smooth nucleophilic addition to α,β-unsaturated compounds in the presence of a catalytic amount of silica-supported aluminum chloride at 60°C and under solvent-free conditions to produce the corresponding β-amino compounds in excellent yields. This method is simple and convenient and works efficiently under mild conditions. This catalyst can used again without losing its activity three times. Copyright Taylor & Francis Group, LLC.
- Saidi, Mohammad R.,Pourshojaei, Yaghoub,Aryanasab, Fezzeh
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experimental part
p. 1109 - 1119
(2009/09/08)
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- ZrOCl2·8H2O on montmorillonite K10 accelerated conjugate addition of amines to α,β-unsaturated alkenes under solvent-free conditions
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At room temperature, ZrOCl2·8H2O on montmorillonite K10 efficiently catalyzes conjugate addition of amines to a variety of conjugated alkenes such as α,β-unsaturated carbonyl compounds, carboxylic esters, nitriles and amides under solvent-free conditions. The catalyst can be recycled for subsequent reactions without any appreciable loss of efficiency.
- Hashemi, Mohammed M.,Eftekhari-Sis, Bagher,Abdollahifar, Amir,Khalili, Behzad
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p. 672 - 677
(2007/10/03)
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- β-Cyclodextrin promoted aza-Michael addition of amines to conjugated alkenes in water
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Highly efficient and environmentally benign aza-Michael additions of amines to α,β-unsaturated compounds catalyzed by β-cyclodextrin in water to produce the corresponding β-amino compounds in excellent yields under mild conditions are described. β-Cyclodextrin can be recovered and reused in subsequent reactions without loss of activity.
- Surendra,Krishnaveni, N. Srilakshmi,Sridhar,Rao, K. Rama
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p. 2125 - 2127
(2007/10/03)
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- [HP(HNCH2CH2)3N]NO3: An efficient homogeneous and solid-supported promoter for aza and thia-Michael reactions and for Strecker reactions
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In the presence of a catalytic amount of an azaphosphatrane nitrate salt, amines and thiols react readily with Michael acceptors. The salt is also an efficient promoter for the one pot synthesis of α-amino and α-amidonitriles. By anchoring the salt to Merrifield Resin, a reusable heterogeneous catalyst is obtained for these reactions. Evidence is presented for catalysis being attributable solely to the NO3- ion.
- Fetterly, Brandon M.,Jana, Nirmal K.,Verkade, John G.
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p. 440 - 456
(2007/10/03)
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- Anti-Markovnikov N-H and O-H additions to electron-deficient olefins catalyzed by well-defined Cu(I) anilido, ethoxide, and phenoxide systems
-
The monomeric Cu(I) complexes (IPr)Cu(Z) (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene, Z = NHPh, OEt, or OPh) react with YH (Y = PhNH, PhCH2NH, EtO, or PhO) to catalytically add Y-H bonds across the C=C bond of electron-deficient olefins to yield anti-Markovnikov organic products. Catalytic activity has been observed for olefins CH2C(H)(X) with X = CN, C(O)Me, or CO2Me as well as crotononitrile. Preliminary studies implicate an intermediate in which the C-Y bond forms through a nucleophilic addition pathway. Copyright
- Munro-Leighton, Colleen,Blue, Elizabeth D.,Gunnoe, T. Brent
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p. 1446 - 1447
(2007/10/03)
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- Covert Mannich reaction via carbon transfer
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1,3-Dimethylbenzimidazolidine reacts with ketones, which can provide activating α hydrogens and primary or secondary amines under acidic conditions, to yield aminomethylation derivatives by a covert Mannich reaction. Copyright Taylor & Francis Group, LLC.
- Gu, Huan,Guo, Yuan,Shi, Zhen
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p. 3335 - 3338
(2007/10/03)
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- The ionic liquid ethyltri-n-butylphosphonium tosylate as solvent for the acid-catalysed hetero-Michael reaction
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A new and convenient method for the acid-catalysed Michael addition reactions of alcohols, thiols and amines to methyl vinyl ketone has been developed using the ionic liquid ethyltri-n-butylphosphonium tosylate. The reaction conditions are mild and obviat
- Karodia, Nazira,Liu, Xihan,Ludley, Petra,Pletsas, Dimitrios,Stevenson, Grace
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p. 11039 - 11043
(2007/10/03)
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- Micellar solution of sodium dodecyl sulfate (SDS) catalyzes facile Michael addition of amines and thiols to α,β-unsaturated ketones in water under neutral conditions
-
Sodium dodecyl sulfate (SDS) catalyzes facile Michael additions of amines and thiols to α,β-unsaturated ketones under neutral micellar conditions to afford the corresponding Michael adducts in good to high yields.
- Firouzabadi,Iranpoor,Jafari
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p. 655 - 661
(2007/10/03)
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- LiClO4 accelerated Michael addition of amines to α,β-unsaturated olefins under solvent-free conditions
-
Several primary and secondary amines were added to α,β- unsaturated esters, nitriles, amides, and ketones to give the corresponding saturated amines mediated by solid lithium perchlorate under solvent-free and environmentally friendly conditions at room temperature.
- Azizi, Najmedin,Saidi, Mohammad R.
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p. 383 - 387
(2007/10/03)
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- A general, polymer-supported acid catalyzed hetero-Michael addition
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Hetero-Michael additions of nitrogen, oxygen and sulfur nucleophiles to α,β-unsaturated ketones were efficiently catalyzed by Nation SAC-13 perfluorinated resinsulfonic acid.
- Wabnitz, Tobias C.,Yu, Jin-Quan,Spencer, Jonathan B.
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p. 1070 - 1072
(2007/10/03)
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- A general, Bronsted acid-catalyzed hetero-Michael addition of nitrogen, oxygen, and sulfur nucleophiles
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(Matrix presented) Strong Bronsted acids such as bis(trifluoromethanesulfon)imide catalyze the hetero-Michael addition of carbamates, alcohols, and thiols to α,β-unsaturated ketones, alkylidene malonates, and acrylimides. Scope, reaction rates, and yields are superior to comparable Lewis acid-catalyzed processes.
- Wabnitz, Tobias C.,Spencer, Jonathan B.
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p. 2141 - 2144
(2007/10/03)
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- The reaction of dimethyltitanocene with N-substituted-β-lactams
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2-Methyleneazetidines have been synthesized and isolated by the reaction of β-lactams with dimethyltitanocene, followed by chromatography on deactivated silica. Efficient conversion required that the lactam nitrogen be strongly deactivated. Methyl transfe
- Martínez, Isamir,Howell, Amy R.
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p. 5607 - 5611
(2007/10/03)
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- Studies on the Fischer Indole Synthesis: Rearrangements of Five-, Six- and Seven-membered Cyclic Hydrazones of Pyrazoline, Tetrahydropyridazine and Tetrahydro-1,2-diazepine Series in Polyphosphoric Acid
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The rearrangements of a few cyclic phenylhydrazones structurally related to 1-phenyl-Δ2-pyrazoline, 1-phenyl-1,4,5,6-tetrahydropyridazine, and 1-phenyl-4,5,6,7-tetrahydro-1,2-diazepine in hot polyphosphoric acid (PPA) are described.The five-membered-ring substrates (the pyrazolines) did not undergo the sigmatropic rearrangement typical of the Fischer indolization, the main reaction course being homolytic N-N bond cleavage, leading to benzidine and its 4-(2-benzoylethyl)-4'-(3-phenyl-Δ2-pyrazolin-1-yl) derivative.The six-membered heterocycles underwent two different reactions, both involving the tautomeric enehydrazine form: the first one is the sigmatropic rearrangement, expected for open-chain hydrazones, affording 4-acyl-1,2,3,4-tetrahydroquinoline derivatives; the second one is a retro-Diels-Alder reaction producing methyleneaniline and α,β-unsaturated carbonyl compounds.The seven-membered-ring substrate gave a 5-acyltetrahydrobenzazepine, resulting from the rearrangement, together with both a pyrrolidine and a pyrazine by-product; their formation involves homolytic N-N bond cleavage of the ring, a δ hydrogen abstraction, followed by intramolecular or intermolecular ring closure.Chemical proofs are given for the new structures.
- Benincori, Tiziana,Brenna, Elisabetta,Sannicolo, Franco
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p. 2139 - 2145
(2007/10/02)
-