- Chiral oxazoline ligands with two different six-membered azaheteroaromatic rings - Synthesis and application in the Cu-catalyzed nitroaldol reaction
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Synthesis and catalytic activity of chiral ligands 5,6-diphenyl-3-{3-[(4S/R)-4-R/Ar-4,5-dihydro-1,3-oxazol-2-yl]pyridin-2-yl}amino-1,2,4-triazines 2 and their analogs 3 possessing an N-oxide function in the pyridine ring are described. The pivotal step in the synthesis of ligands 2 is the Buchwald-Hartwig Pd-catalyzed cross-coupling reaction between 3-bromo-5,6-diphenyl-1,2,4-triazine (7a) and enantiopure 3-(4,5-dihydro-1,3-oxazol-2-yl)pyridin-2-amines 6a-d. Aromatic nucleophilic substitution of chlorine in 3-chloro-5,6-diphenyl-1,2,4-triazine (7b) with 3-(4,5-dihydro-1,3-oxazol-2-yl)pyridin-2-amine 1-oxides 12 was investigated as the key reaction in the synthesis of ligands 3. Two undesired derivatives 13 or 14, resulting from unexpected reactions of 3, were isolated depending on reaction conditions. Compounds 2 and 3 as well as the side products 13 and 14 were screened as chiral ligands in the copper catalyzed enatioselective nitroaldol reaction.
- Wolińska, Ewa
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Read Online
- Structural characterization of copper complexes with chiral 1,2,4-triazine-oxazoline ligands
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The crystal structure determination of oxazoline-1,2,4-triazine ligand 1f and pyridine-oxazoline ligand 2g was used to analyze their conformational preferences when forming complexes with metals. Proton nuclear magnetic resonance (1H NMR), electrospray ionization mass spectrometry and UV-vis spectroscopy as well as theoretical calculation using molecular mechanics (MM) were adopted to study the composition and geometry of oxazoline-1,2,4-triazine ligands 1 complexes with copper(II) acetate monohydrate. The study revealed that during the complexation, (i) Cu(II) ion is reduced to Cu(I) upon the ligand-to-metal charge transfer transition and (ii) the ligands form with copper(I) 2:1 (L:Cu) complexes of tetrahedral geometry. On the basis of the findings, the catalytic cycle and the active transition state for the enantioselective nitroaldol reaction (the Henry reaction) catalyzed by 1-Cu are proposed.
- Wolińska, Ewa,Karczmarzyk, Zbigniew,Wysocki, Waldemar
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- Highly efficient nanosized mesoporous CuMgAl ternary oxide catalyst
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Highly efficient nanosized mesoporous CuMgAl ternary oxide catalysts are provided.
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Page/Page column 17; 21; 22
(2021/07/01)
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- Polymeric nanoassembly of imine functionalized magnetite for loading copper salts to catalyze Henry and A3-coupling reactions
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Poly(ethylenimine) was grafted on the magnetite (Fe3O4) nanoparticles, and subsequently reacted with different aldehydes to form the imine functionalities (Fe3O4-Imine NPs). Thus formed Fe3O4/su
- Rathod, Prakash B.,Kumar, K.S. Ajish,Athawale, Anjali A.,Pandey, Ashok K.
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- Synthesis of nitroaldols through the Henry reaction using a copper(II)–Schiff base complex anchored on magnetite nanoparticles as a heterogeneous nanocatalyst
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A Cu(II)-Schiff base complex supported on functionalized Fe3O4 magnetic nanoparticles (MNPs@Salen-Cu(II)) was obtained as a new heterogeneous nanocatalyst. The nanocomposite materials were characterized by vibrating sample magnetometer (VSM), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). The catalyst was used in the Henry reaction in order to accomplish one-pot synthesis of nitroaldol derivatives in green conditions. This nanocatalyst can be easily separated from media of reaction using an external magnet and reused several times without loss of its catalytic activity. Furthermore, the non-toxicity of the catalysts and the high yield of the products are other advantages of this method.
- Parandeh-Khoozani, Niloufar,Moradian, Mohsen
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p. 2035 - 2054
(2021/05/21)
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- Design, synthesis and structure-activity evaluation of novel 2-pyridone-based inhibitors of α-synuclein aggregation with potentially improved BBB permeability
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The treatment of Parkinson's disease (PD), the second most common neurodegenerative human disorder, continues to be symptomatic. Development of drugs able to stop or at least slowdown PD progression would benefit several million people worldwide. SynuClea
- Díaz-de-Villegas, María D.,Gálvez, José A.,José Galano-Frutos, Juan,Mahía, Alejandro,Navarro, Susanna,Pallarés, Irantzu,Pe?a-Díaz, Samuel,Pujols, Jordi,Sancho, Javier,Ventura, Salvador
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- Accelerating the optimization of enzyme-catalyzed synthesis conditionsviamachine learning and reactivity descriptors
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Enzyme-catalyzed synthesis reactions are of crucial importance for a wide range of applications. An accurate and rapid selection of optimal synthesis conditions is crucial and challenging for both human knowledge and computer predictions. In this work, a
- Liang, Jinhu,Liu, Dongchang,Wan, Zhongyu,Wang, Quan-De
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supporting information
p. 6267 - 6273
(2021/07/28)
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- One-Pot Enzyme Cascade Catalyzed Asymmetrization of Primary Alcohols: Synthesis of Enantiocomplementary Chiral β-Nitroalcohols
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Biocatalytic asymmetrization of inexpensive and stable primary alcohols to prepare enantioenriched β-nitroalcohols is an important development in green chemistry for the production of chiral pharmaceutical intermediates. Herein, we report a one-pot, two-step cascade reaction sequence in which first benzylic alcohols were oxidized to produce corresponding benzaldehydes using horse liver alcohol dehydrogenase (HLADH). The in situ generated aldehydes were then reacted in a biphasic medium with nitromethane by Arabidopsis thaliana hydroxynitrile lyase (AtHNL) or Baliospermum montanum HNL (BmHNL) catalyzed Henry reaction to produce stereoselective β-nitroalcohols with (R) or (S) configuration, respectively. Using HLADH-AtHNL, (R)-β-nitroalcohols were obtained in up to 64% conversion, and HLADH-BmHNL, (S)-β-nitroalcohols in up to 70% conversion, while in both cases excellent stereoselectivity (up to >99% ee) was achieved. The concept was proven by functionalization of sp3 C?H bond of ten simple achiral benzylic alcohols to enantiocomplementary chiral β-nitroalcohols. (Figure presented.).
- Chatterjee, Ayon,Kumar Padhi, Santosh,Rao, D. H. Sreenivasa
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supporting information
p. 5310 - 5318
(2021/10/02)
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- A urea-containing metal-organic framework as a multifunctional heterogeneous hydrogen bond-donating catalyst
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A urea-containing metal-organic framework (MOF) was synthesized from a V-shaped dicarboxylate ligand and Cu(II) ions. As the undesirable self-aggregation of the urea moiety has been prohibited in the framework, this MOF can act as a heterogeneous hydrogen
- Zhu, Chengfeng,Tang, Haitong,Yang, Keke,Wu, Xiang,Luo, Yunfei,Wang, Jin,Li, Yougui
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- Waste-to-useful: A biowaste-derived heterogeneous catalyst for a green and sustainable Henry reaction
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Owing to the depletion of resources coupled with increasing waste generation, the conversion of waste biomass to value-added materials has gained interest. Here, we report for the first time the application of Musa acuminata (banana) peel ash (MAPA) as a heterogeneous catalyst for C-C bond formation via a Henry reaction under solvent-free conditions at ambient temperature. The catalyst was well characterized using different analytical techniques like FT-IR, SEM, TEM-EDS, XRD, XRF, XPS, BET and TGA, along with basicity determination by a Hammett indicator test and titration method. An excellent yield of nitroalcohol was obtained within 15-30 minutes. No dehydrated product was observed. The catalyst used in these studies has the advantage of being a waste material and is hence low-cost, easily prepared, recyclable and environmentally friendly. In addition, the use of a biogenic renewable catalyst, its atom economy, and room temperature and solvent-free reaction conditions and the avoidance of column chromatography make the protocol highly significant from green and sustainable chemistry perspectives.
- Rajkumari, Kalyani,Das, Diparjun,Pathak, Gunindra,Rokhum, Lalthazuala
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p. 2134 - 2140
(2019/02/05)
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- Daucus carota root enzyme catalyzed Henry reaction: A green approach
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Enzyme from Daucus carota root catalyzed Henry reaction of substituted benzaldehydes and nitromethane in phosphate buffer of pH 7 at 28 °C to afford β-nitroalcohols in excellent yields (up to 94%).
- Acharya, Chiranjit,Achari, Anushree,Jaisankar, Parasuraman
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p. 663 - 666
(2018/01/18)
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- An ionic liquid gel: A heterogeneous catalyst for Erlenmeyer-Plochl and Henry reactions
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An ionic liquid gel has been prepared by entrapping 1-butyl-3-methylimidazolium hydroxide ([Bmim]OH) in an aqueous agar gel. The ionic liquid gel has been characterized by Fourier transform infrared (FT-IR), Fourier transform Raman (FT-Raman) spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and energy dispersive X-ray analysis (EDX). The ionic liquid gel has been successfully employed as a heterogeneous catalyst in the Erlenmeyer-Plochl reaction involving aldehydes, hippuric acid and acetic anhydride as well as in the Henry reaction between aldehydes and nitromethane in ethanol at room temperature. The heterogeneity of the ionic liquid gel has been confirmed by conducting hot filtration tests and leaching studies. Additionally, the ionic liquid gel could be easily recovered by simple filtration and reused five times without significant loss in catalytic activity.
- Jagadale, Megha,Naikwade, Altafhusen,Salunkhe, Rajashri,Rajmane, Mohan,Rashinkar, Gajanan
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p. 10993 - 11005
(2018/07/06)
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- Preparation method of 1-phenyl-2-nitroethanol and derivate thereof
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The invention discloses a preparation method of 1-phenyl-2-nitroethanol and a derivate thereof. The preparation method is characterized in that benzaldehyde or a derivate thereof and nitromethane aretreated as raw materials; tertiary butanol is treated as
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Paragraph 0030-0034
(2019/01/14)
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- A metalloligand appended with benzimidazole rings: Tetranuclear [CoZn3] and [CoCd3] complexes and their catalytic applications
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A novel Co3+-based metalloligand 1 offering appended benzimidazole rings has been prepared and utilized for the synthesis of tetranuclear [CoZn3] (2 and 2-Cl) and [CoCd3] (3) heterometallic coordination complexes (HCCs). C
- Pandey, Saurabh,Bansal, Deepak,Gupta, Rajeev
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p. 9847 - 9856
(2018/06/18)
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- Bottom-Up Assembly of a Highly Efficient Metal-Organic Framework for Cooperative Catalysis
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In this study, we demonstrate a bottom-up assembly of a monomeric copper complex and a two-dimensional (2-D) heterometallic metal-organic framework (MOF) from a carboxylate-functionalized tridentate Schiff base ligand and metal ions. The obtained 2-D MOF
- Li, Changda,Tang, Haitong,Fang, Yu,Xiao, Zhifeng,Wang, Kunyu,Wu, Xiang,Niu, Helin,Zhu, Chengfeng,Zhou, Hong-Cai
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supporting information
p. 13912 - 13919
(2018/10/20)
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- A double-chiral amino alcohol compound and its preparation method and application
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The invention discloses a bis-chiral alkamine compound and a preparation method therefor and application thereof. A chiral ligand is selected and synthesized to prepare a chiral catalyst. The chemical name of the compound is N,N'-bis[(1S)-2-hydroxyl-1-ary
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Page/Page column 0042; 0043; 0044; 0045; 0046
(2017/08/25)
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- A NbO type Cu(II) metal-organic framework showing efficient catalytic activity in the Friedl?nder and Henry reactions
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A three-dimensional NbO type porous metal-organic framework 1 containing both tertiary amine groups and paddle wheel dinuclear Cu2(COO)4 secondary building units as the active centre was synthesized at room temperature. The activated
- Gupta, Anoop K.,De, Dinesh,Bharadwaj, Parimal K.
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p. 7782 - 7790
(2017/07/11)
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- Biphenyl-Based Bis(thiourea) Organocatalyst for Asymmetric and syn -Selective Henry Reaction
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A scalable, efficient and chromatography-free synthesis of a new enantiopure C 2-symmetric bis(thiourea) catalyst was accomplished from a readily available starting material. The developed strategy could be conducted on a multi-gram scale. Both the prepared enantiomers of the bis(thiourea) organocatalyst have been tested in the asymmetric Henry reaction under thoroughly optimized conditions during which an unusual solvent effect on enantioselectivity was found. The corresponding adducts were obtained in excellent yields with good to excellent enantioselectivities. The achieved high reactivity and enantioselectivity in the nitroaldol reaction of nitroalkanes with aromatic aldehydes suggests promising potential for this catalyst. Moreover, a significant syn-diastereoselectivity was observed.
- Otevrel, Jan,Bobal, Pavel
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supporting information
p. 593 - 603
(2017/01/25)
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- A porous two-dimensional Zn(II)-coordination polymer exhibiting SC-SC transmetalation with Cu(II): Efficient heterogeneous catalysis for the Henry reaction and detection of nitro explosives
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The linker 5-(benzylamino)isophthalic acid (H2L) forms a robust 2D Zn(ii)-coordination polymer, {[Zn8(L)6(μ3-OH)4(H2O)6]·(DMF)·(H2O)2.5}n(1Z
- Gupta, Mayank,De, Dinesh,Pal, Sanchari,Pal, Tapan K.,Tomar, Kapil
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supporting information
p. 7619 - 7627
(2017/07/10)
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- Copper-Catalyzed N-Arylation of Nitroenamines with Diaryliodonium Salts
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A novel synthetic methodology was developed for the N-arylation of nitroenamine derivatives utilizing diaryliodonium triflates and copper(I) chloride as a catalyst. The procedure enables the easy aryl transfer from the hypervalent species under mild catalytic conditions with unusual heteroatom preference and high efficiency.
- Aradi, Klára,Mészáros, ádám,Tóth, Balázs L.,Vincze, Zoltán,Novák, Zoltán
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p. 11752 - 11764
(2017/11/24)
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- Copper-bearing chirality helical coordination polymer and preparation method and application thereof
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The invention discloses a copper-bearing chirality helical coordination polymer and a preparation method and application thereof. The chemical formula is {[Cu (R,R-cdpa) (H2O)2].2NO3. 2H2O}. The preparation method comprises the steps of adding 5 mL of methanol solution into copper dinitrate-water(1/3) and R,R-cdpa to be mixed to obtain suspension liquid and enabling the suspension liquid to stand at room temperature to obtain the copper-bearing chirality helical coordination polymer. The copper-bearing chirality helical coordination polymer has the advantages that a double chelate ligand R,R-cdpa based on chiraity cyclohexanediamine and Cu (II) are utilized to prepare a one-dimensional helical coordination polymer, and the coordination polymer has a right hand 31 helical structure and has second-order non-linear optical activity. The preparing technology is simple, a complex synthesis device is not needed, the production cost is reduced, and the prepared coordination polymer can be applied to asymmetric Henry reaction of aromatic aldehyde and nitromethane.
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Paragraph 0022; 0023; 0024; 0027
(2016/11/21)
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- Henry reaction catalyzed by recyclable [C4dabco]OH ionic liquid
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DABCO-based ionic liquid, 1-butyl-4-aza-1-azaniabicyclo[2.2.2]octane hydroxide, has been used as an efficient catalyst for Henry reaction of various carbonyl compounds with nitroalkanes affording very high yields within a short duration. This method is very simple, clean and avoids hazardous organic solvents. The catalyst can be easily recovered and recycled several times.
- Keithellakpam, Sanjoy,Laitonjam, Warjeet S.
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p. 110 - 113
(2016/02/26)
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- Henry reaction catalyzed by recyclable [C4dabco]OH ionic liquid
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DABCO-based ionic liquid, 1-butyl-4-aza-1-azaniabicyclo[2.2.2]octane hydroxide, has been used as an efficient catalyst for Henry reaction of various carbonyl compounds with nitroalkanes affording very high yields within a short duration. This method is very simple, clean and avoids hazardous organic solvents. The catalyst can be easily recovered and recycled several times.
- Keithellakpam, Sanjoy,Laitonjam, Warjeet S.
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p. 110 - 113
(2017/01/18)
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- Microporous polyurethane material for size selective heterogeneous catalysis of the Knoevenagel reaction
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The first polyurethane material which is microporous (BET surface area of 312 m2 g-1) is prepared by solvothermal synthesis and acts as highly efficient and recyclable heterogeneous catalyst in the Knoevenagel condensation showing si
- Dey, Sandeep Kumar,De Sousa Amadeu, Nader,Janiak, Christoph
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supporting information
p. 7834 - 7837
(2016/07/06)
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- Vasicine from Adhatoda vasica as an organocatalyst for metal-free Henry reaction and reductive heterocyclization of o-nitroacylbenzenes
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Vasicine, a quinazoline alkaloid, from the leaves of Adhatoda vasica, has been utilized as an efficient catalyst for metal and base free Henry reaction of various aldehydes with nitro alkanes. The method can be used in the synthesis of various β-nitro alcohols under mild reaction conditions without use of hazardous organic solvents and expensive catalysts. Vasicine is also applied successfully for one pot synthesis of 2,1-benzisoxazoles from o-nitroacylbenzenes in good yields under mild conditions.
- Sharma, Sushila,Kumar, Manoranjan,Bhatt, Vinod,Nayal, Onkar S.,Thakur, Maheshwar S.,Kumar, Neeraj,Singh, Bikram,Sharma, Upendra
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supporting information
p. 5003 - 5008
(2016/10/25)
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- Polymer supported DMAP: An easily recyclable organocatalyst for highly atom-economical Henry reaction under solvent-free conditions
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Polymer supported catalysts are regarded as a borderline class of catalysts, which retains the advantages of homogeneous catalysts while securing the ease of recovery by simple filtration and workup of heterogeneous systems. Additionally, such catalysts are less hygroscopic due to the long polymer backbone. Here we have demonstrated that a catalytic amount of polymer supported DMAP (10 mol%) can lead to excellent conversion of an equimolar mixture of aldehyde and nitroalkane exclusively into β-nitroalcohols via the Henry reaction. Unlike most of the commonly used catalysts, polymer supported DMAP can be recovered by simple filtration and reused several times, thereby reducing the operational cost. High synthetic efficiency, total atom economy, near quantitative yields, mild reaction conditions, operational simplicity, easy recovery and reusability of the catalyst, solvent-free reaction conditions and avoidance of traditional reaction workup make the protocol highly significant from Green and Sustainable Chemistry perspectives.
- Das, Diparjun,Pathak, Gunindra,Rokhum, Lalthazuala
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p. 104154 - 104163
(2016/11/17)
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- Dendronized piperidine: Highly effective and recyclable catalysts for Henry reaction
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Two types of dendronized tertiary amines were synthesized by attaching piperidine to the core of a Fréchet-type dendrimer or to the end of an alkyl chain that is linked to the dendritic core. The relationship between structure and property of the catalysts in the Henry reaction of 2-nitrobenzaldehyde and nitromethane was established. It was observed that the attachment of piperidine to the dendritic sector by using a hexamethylene chain effectively avoids the scenario of dendritic shell encapsulation. And the 4-G3′ catalyst of third-generation with dendritic link exhibits excellent catalytic performance, and can be recycled ten times without a significant loss of activity.
- Yi, Bing,Yin, Yanyan,Yi, Ziqi,Zhou, Wei,Liu, Haitao,Tan, Nianyuan,Yang, Hai
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supporting information
p. 2320 - 2323
(2016/05/10)
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- Application of natural feedstock extract: The Henry reaction
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For the first time, we have successfully performed the Henry reaction in neat 'Natural Feedstock Extract' at room temperature. Herein, we used two most abundant natural feedstock extracts such as 'Water Extract of Banana' (WEB) and 'Water Extract of Rice Straw Ash' (WERSA). This protocol is highly advantageous owing to the employment of natural feedstock as green reaction media resulting in significant novelty and advancement with respect to green and sustainable chemistry.
- Surneni, Naresh,Barua, Nabin C.,Saikia, Bishwajit
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supporting information
p. 2814 - 2817
(2016/06/09)
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- Ba/ZrO2 nanoparticles as efficient heterogeneous base catalyst for the synthesis of β-nitro alcohols and 2-amino 2-chromenes
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Zirconia nanoparticles were synthesized by precipitation, urea hydrolysis, amorphous citrate and combustion synthesis methods. The zirconia surface was subsequently modified by grafting Ba 2+ species. The Ba 2+ modified zirconia (Ba/ZrO 2) materials were characterized using XRD, Fourier analysis, UV-vis-DRS, FESEM and HRTEM techniques. XRD study indicated selective stabilization of the tetragonal phase of zirconia in the presence of Ba 2+ species. Fourier line profile analysis of the XRD peaks revealed that the average crystallite size of the zirconia nanoparticles is in the range of 5-15 nm. The surface area, basicity and barium content of the material depend strongly on the method of synthesis. The Ba/ZrO 2 catalyst prepared by urea hydrolysis method exhibited higher surface area and barium content compared to other samples. The catalytic activity of the Ba/ZrO 2 catalyst was evaluated for synthesis of β-nitro alcohols and 2-amino 2-chromenes. The β-nitro alcohols were synthesized by condensation of aryl aldehydes and nitromethane. Similarly, the 2-amino 2-chromenes were synthesized by condensation of arylaldehydes, α-naphthol and malononitrile. The Ba/ZrO 2 catalyst was found to be highly efficient for synthesis of both classes of compounds providing excellent yield and purity of the products. [Figure not available: see fulltext.]
- Pradhan, Sagnika,Swarnima, Kumari,Mishra
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p. 1119 - 1130
(2016/07/15)
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- Keratin protein-catalyzed nitroaldol (henry) reaction and comparison with other biopolymers
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Here we describe a preliminary investigation on the ability of natural keratin to catalyze the nitroaldol (Henry) reaction between aldehydes and nitroalkanes. Both aromatic and heteroaromatic aldehydes bearing strong or moderate electron-withdrawing group
- H?ring, Marleen,Pettignano, Asja,Quignard, Fran?oise,Tanchoux, Nathalie,Díaz, David Díaz
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- Right-handed 4 helix coordination polymer and its preparation method and use
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The invention discloses a right-handed 4 helix coordination polymer and its preparation method and use. The right-handed 4 helix coordination polymer has a chemical formula of {[Cu(R, R-cdmp)(H2O)]. 2NO3. 2H2O}n. The preparation method comprises add
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Paragraph 0022; 0023; 0024; 0025; 0026; 0027
(2016/11/28)
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- Selective synthesis of nitroalcohols in the presence of Ambersep 900 OH as heterogeneous catalyst
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Abstract A green protocol has been developed for the selective synthesis of β-nitroalcohols using commercially available Ambersep 900 OH as reusable heterogeneous catalyst. The reaction between aldehyde and nitromethane was performed under solvent-free condition at room temperature within a short time (70-150 min) in the presence of 10 wt % of Ambersep 900 OH to produce corresponding nitroalcohols in high yield (72-91 %). After the reaction is over, the catalyst can be separated and reused (3 cycles) without appreciable loss in its activity.
- Lodh, Rajsekhar,Sarma, Manas Jyoti,Borah, Arun Jyoti,Phukan, Prodeep
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p. 969 - 972
(2015/02/19)
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- Synthesis of high surface area mixed metal oxide from the NiMgAl LDH precursor for nitro-aldol condensation reaction
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We have investigated the effect of divalent metal cations on the structural and catalytic activity of MgAl-layered double hydroxide (LDH), by partially substituting Mg2+ with M2+ (M2+ = Ni2+ or Co2+)
- Bharali, Dipshikha,Devi, Rasna,Bharali, Pankaj,Deka, Ramesh C.
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p. 172 - 178
(2015/02/19)
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- Merging Asymmetric Henry Reaction with Organocatalytic Cascade Reaction for the Construction of a Chiral Indolizidine Alkaloid Skeleton
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A sequential reaction combining the copper-catalyzed asymmetric Henry reaction with the organocatalytic Michael addition-hemiacetalization cascade reaction was developed. The C1-symmetric chiral diamine L1-copper complex was responsible for the first highly enantioselective Henry reaction, while diphenylprolinol silyl ether A acted as effective organocatalyst for the second cascade reaction between chiral β-nitro alcohol and α,β-unsaturated aldehydes. Via rational design and combination of the two independent catalytic systems, good yields and excellent enantioselectivities and diastereoselectivities were achieved for a broad substrate scope under mild reaction conditions. The synthetic utility of this sequential catalytic asymmetric cascade reaction was demonstrated as an alternative and straightforward stereoselective synthesis strategy for chiral indolizidine alkaloid and its analogues.
- Zhou, Yirong,Yang, Qin,Shen, Jian,Chen, Xin,Peng, Yiyuan,Gong, Yuefa
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p. 1446 - 1456
(2015/02/19)
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- Evaluation of the nitroaldol reaction in the presence of metal ion-crosslinked alginates
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Understanding the ability of biopolymers to promote selective C-C bond formation could provide important insights into the molecular mechanisms underlying evolution, and could help in the design of safer and "greener" catalysts in the future. This work de
- Kühbeck, Dennis,Mayr, Judith,H?ring, Marleen,Hofmann, Martin,Quignard, Fran?oise,Díaz Díaz, David
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p. 2306 - 2315
(2015/03/18)
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- DNA-catalyzed Henry reaction in pure water and the striking influence of organic buffer systems
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In this manuscript we report a critical evaluation of the ability of natural DNA to mediate the nitroaldol (Henry) reaction at physiological temperature in pure water. Under these conditions, no background reaction took place (i.e., control experiment wit
- H?ring, Marleen,Pérez-Madrigal, Maria M.,Kühbeck, Dennis,Pettignano, Asja,Quignard, Fran?oise,Díaz, David Díaz
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p. 4136 - 4147
(2015/05/06)
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- Simple route to multisubstituted tetrahydropyrimidines
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Abstract As part of our ongoing investigation into the synthetic application of nitroenamines several new densely substituted pyrimidine and pyrrolo-pyrimidine derivatives were prepared. Thus, 2-nitromethylenepyrrolidine and some open chain nitroenamines of phenyl-(2-nitro-1-phenyl-vinyl)-amine type were reacted with ethyl glyoxylate and a substituted aniline usually in a one-pot procedure to furnish the key intermediates for a subsequent cyclization. These compounds including a molecular fragment of 1,3-diamine type were subjected to a simple ring closure with formaldehyde to give the title compounds in good yields. The protocol reported has the advantages of mild reaction conditions, easy workup and inexpensive reagents. In an attempted removal of the 4-methoxy-phenyl protecting group from the 4-methoxy-phenyl substituted hexahydropyrrolo[1,2-c]pyrimidine derivative, an unexpected periodic acid mediated ring cleavage and phenyl group migration was discovered. The structures of the synthesized new compounds were confirmed by spectral data, and, particularly, the hindered rotation and the unusual 1H NMR characteristics of 4-(4-nitro-phenyl)-but-3-enoic acid ethyl ester derivative were discussed.
- Vincze, Zoltán,Pilipecz, Mihály V.,Scheiber, Pál,Varga, Tamás R.,Tóth, Gábor,Nemes, Péter
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p. 6135 - 6142
(2015/08/03)
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- Hyperbranched polyamines: Tunable catalysts for the Henry reaction
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Hyperbranched polyethylenimine derivatives were successfully employed as catalyst in the Henry reaction. The nitroalcohol products were obtained in excellent yields within short reaction times. A one-pot synthesis of β-nitrostyrenes was developed by using ZnCl2 along with hyperbranched polyethylenimine derivatives. Georg Thieme Verlag Stuttgart New York.
- Ganesan, Subramaniapillai Selva,Ganesan, Asaithampi,Kothandapani, Jagatheeswaran
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supporting information
p. 1847 - 1850
(2014/08/18)
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- Catalytic applications of an organosuperbase dendron grafted on mesoporous SBA-15 and a related palladium complex in Henry and Suzuki-Miyaura coupling reactions
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An efficient synthetic method for the synthesis of a basic amine dendron grafted on SBA-15 and a related Pd(II) complex as two novel catalysts has been developed. The prepared catalysts were evaluated in Henry and Suzuki-Miyaura coupling reactions and were found to exhibit excellent heterogeneous catalytic activity in green media, and could be easily separated and reused several times.
- Veisi, Hojat,Kordestani, Davood,Hemmati, Saba,Faraji, Ali Reza,Veisi, Hamed
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supporting information
p. 5311 - 5314
(2015/01/09)
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- Investigation of structural change and basicity of NaY zeolite upon loading KF and their application in Henry nitroaldol reaction under microwave irradiation condition
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Potassium salt modified NaY zeolite along with methanol-water mixture as solvent under microwave irradiation offers an environmentally benign way to synthesize b-nitroalcohols rapidly with excellent yield and selectivities. Here, NaY zeolite was modified
- Devi, Rasna,Borah, Ruli,Deka, Ramesh C.
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p. 1751 - 1758
(2015/02/19)
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- (2S,5R)-2-Methylaminomethyl-1-methyl-5-phenylpyrrolidine, a chiral diamine ligand for copper(ii)-catalysed Henry reactions with superb enantiocontrol
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A cis-2-aminomethyl-5-phenylpyrrolidine, which is easily available from methyl Boc-l-pyroglutamate, was found to be a highly efficient chiral ligand for Cu(ii)-catalysed Henry reactions. Excellent yields (>90%) and superb levels of enantiocontrol (98.5-99.6% ee) were reached with aromatic, heteroaromatic, vinylic, and aliphatic aldehydes (36 examples). This journal is the Partner Organisations 2014.
- Scharnagel, Dagmar,Prause, Felix,Kaldun, Johannes,Haase, Robert G.,Breuning, Matthias
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supporting information
p. 6623 - 6625
(2014/06/10)
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- Highly efficient and large-scalable glucoamylase-catalyzed Henry reactions
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Eco-friendly, highly efficient and large-scalable Henry reactions of aromatic aldehydes and nitroalkanes catalyzed by glucoamylase from Aspergillus niger (AnGA) are described. The reactions were carried out at 30 °C in the mixed solvents of ethanol and wa
- Gao, Na,Chen, Yan-Li,He, Yan-Hong,Guan, Zhi
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p. 16850 - 16856
(2013/09/23)
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- Ethyl acrylate conjugated polystyryl-diphenylphosphine - An extremely efficient catalyst for Henry reaction under solvent-free conditions (SolFC)
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Over the last few decades, the fast-growing development of polymer supported reagents has led to the synthesis of a variety of reagents on solid support. Some of the major advantages of using such reagents are that they are less hygroscopic, easy to recover, and can be recycled. Here, we have demonstrated that in situ generated ethyl acrylate conjugated polystyryl-diphenylphosphine (PDPP-EA) derived from the reaction of a mixture of polystyryl-diphenylphosphine and ethyl acrylate in a stoichiometric ratio can efficiently catalyze the synthesis of β-nitroalcohols from the reaction of aldehydes and nitroalkanes under solvent-free conditions (SolFC).
- Rokhum, Lalthazuala,Bez, Ghanashyam
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p. 300 - 306
(2013/06/05)
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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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- 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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- Chemoselective Henry reaction catalyzed by electro-generated base
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Chemoselective synthesis of 2-nitroalkanols catalyzed by electro-generated base (EGBs) in the presence of acetonitrile and lithium perchlorate has been studied by cyclic voltammetry and controlled potential electrolysis techniques. Cathodic reduction of nitromethane at platinum cathode produces organic anion which acts as EGBs and undergoes condensation with carbonyl group of substituted aldehydic substrate to produce 2-nitroalkanols in 75-85 % yields. The controlled nucleophilicity of EGBs in organic solvent during electrochemical reaction makes it chemoselective which is a unique feature of this work.
- Saraswat,Sharma,Singh,Siddiqui,Singh
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p. 1393 - 1399
(2013/06/05)
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- The henry reaction in [Bmim][PF6]-based microemulsions promoted by acylase
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An environmentally-friendly, enzyme-promoted procedure for the Henry reaction was first studied using water-in-[Bmim][PF6] microemulsions as reaction medium. The Amano acylase from Aspergillus oryzae showed better catalytic activity for the addition reactions of nitromethane with a series of aromatic aldehydes, and a highest yield of 90% was obtained.
- Xia, Wen-Jian,Xie, Zong-Bo,Jiang, Guo-Fang,Le, Zhang-Gao
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p. 13910 - 13919
(2014/01/06)
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- C-C bond formation catalyzed by natural gelatin and collagen proteins
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The activity of gelatin and collagen proteins towards C-C bond formation via Henry (nitroaldol) reaction between aldehydes and nitroalkanes is demonstrated for the first time. Among other variables, protein source, physical state and chemical modification
- Kuehbeck, Dennis,Dhar, Basab Bijayi,Schoen, Eva-Maria,Cativiela, Carlos,Gotor-Fernandez, Vicente,Diaz, David Diaz
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supporting information
p. 1111 - 1118
(2013/07/27)
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- One-pot solid phase synthesis of (E)-nitroalkenes
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An efficient one-pot protocol for the synthesis of (E)-nitroalkenes by reaction of aldehydes and nitroalkanes in the presence of polymer-bound triphenylphosphine, iodine and imidazole is described. Although the reaction works with similar efficiency with triphenylphosphine and its polymer-bound version, easy removal of the unwanted polymer-bound triphenylphosphine oxide and its recovery as triphenylphosphine provide the edge for practical application of the method.
- Rokhum, Lalthazuala,Bez, Ghanashyam
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p. 5500 - 5504
(2013/09/23)
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- Asymmetric Henry reaction catalyzed by Cu(I)-based chiral amino alcohol complex
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The Cu(I)-based complex prepared from (S)-2-(furan-2-yl-methylamino)-2- phenylethanol (5c) and CuCl was used as catalyst in enantioselective Henry reactions of arylaldehydes and nitromethane, which gave 89% ee and 95% yield at ambient temperature. The proposed catalytic cycle of an asymmetric Henry reaction was suggested. TUeBITAK.
- Shen, Tianhua,Qin, Quan,Ni, Hang,Xia, Ting,Zhou, Xiaocong,Cui, Funa,Li, Junqi,Ran, Deqiang,Song, Qingbao
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p. 966 - 977
(2013/12/04)
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