- A 1, 3 - dicarbonyl compound synthesis method
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The invention discloses a synthetic method for 1,3-dicarbonyl compound, which belongs to the technical field of organic synthesis of intermediates. The method comprises the following concrete steps: (1) adding acetone, aromatic aldehyde, t-butyl hydropero
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Paragraph 0014; 0015; 0016
(2017/04/22)
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- Direct synthesis of 1,3-dicarbonyl compounds via radical coupling of aldehydes with ketones under metal-free conditions
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An efficient approach for the synthesis of 1,3-diketones from aldehydes and ketones has been developed using Bu4NI (TBAI) as the catalyst. In the presence of DTBP-TBHP/p-TsOH, aldehydes undergo radical coupling with ketones to provide the desired products in moderate to high yields at 120 °C. Although various substituents on the aromatic ring of aldehydes are well tolerable under the standard reaction conditions, the protocol is limited by the scope of ketones. The method exhibits advantages in terms of the easy access of the starting materials, operational simplicity, functional group tolerance, and the absence of metal catalyst.
- Shen, Xuqian,Borah, Arun Jyoti,Cao, Xihan,Pan, Weixiang,Yan, Guobing,Wu, Xiangmei
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supporting information
p. 6484 - 6487
(2015/11/16)
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- Direct route to 1,3-diketones by palladium-catalyzed carbonylative coupling of aryl halides with acetylacetone
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Man up your magnesium! By employing a MgCl2/Et3N system, aryl diketones can be generated from the Pd-catalyzed carbonylative α-arylation of acetylacetone with aryl bromides (see scheme). The method is ideal for the introduction of carbon isotopes into more complex structures, since only stoichiometric amounts of carbon monoxide are employed. Copyright
- Korsager, Signe,Nielsen, Dennis U.,Taaning, Rolf H.,Lindhardt, Anders T.,Skrydstrup, Troels
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supporting information
p. 17687 - 17691
(2014/01/17)
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- Strategy for the synthesis of pyridazine heterocycles and their derivatives
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The first synthesis of novel fused pyridazines has been realized starting from 1,3-diketones involving a Diaza-Wittig reaction as a key step. A convenient strategy was elaborated to access versatile pyridazine derivatives allowing the variation of substituents at position 6 of the heterocyclic ring. In a first part, pyridazines bearing an ester group were synthesized as a model to evaluate the methodology. In a second part, an improved procedure has been used for the synthesis of pyridazines bearing a ketone group and different methods of cyclization were carried out, leading to several hitherto unknown biheterocyclic compounds. This reaction scheme represents an attractive methodology for the synthesis of novel fused pyridazine derivatives.
- Bel Abed, Hassen,Mammoliti, Oscar,Bande, Omprakash,Van Lommen, Guy,Herdewijn, Piet
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p. 7845 - 7858
(2013/09/12)
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- Albumin-directed stereoselective reduction of 1,3-diketones and β-hydroxyketones to anti diols
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The reduction of 1,3-diketones and β-hydroxyketones with NaBH 4 in aqueous acetonitrile is highly stereoselective in the presence of stoichiometric amounts of bovine or human albumin, giving anti 1,3-diols with d.e. up to 96%. The same reaction, without albumin, gives syn and anti 1,3-diols in approximately 1:1 ratio. The presence of an aromatic carbonyl group is essential for diastereoselectivity in the NaBH4/albumin reduction of both 1,3-diketones and β-hydroxyketones. Thus, 3-hydroxy-1-(p-tolyl)-1- butanone is stereoselectively reduced in the presence of albumin, while reduction of its isomer 4-(p-tolyl)-4-hydroxy-2-butanone is not stereoselective. The albumin-controlled reduction is not stereospecific as both enantiomers of 1-aryl-3-hydroxy-1-butanones are reduced to diols with identical stereoselectivities. Circular dichroism of the bound substrates confirms that aromatic ketones are recognized by the protein's IIA binding site. Binding studies also suggest that 1,3-diketones are recognized in their enol form. From the effect of pH on binding of a diketone it is concluded that, in the complex with the substrate, ionizable residues His242 and Lys199 are in the neutral and protonated forms, respectively. A homology model of BSA was obtained and docking of model substrates confirms the preference of the protein for aromatic ketones. Modelling of the complexes with the substrates also allows us to propose a mechanism for the reduction of 1,3-diketones in which the chemoselective reduction of the first (aliphatic) carbonyl is followed by the diastereoselective reduction of the second (aromatic) carbonyl. The role of albumin is thus a combination of chemo- and stereocontrol.
- Berti, Federico,Bincoletto, Simone,Donati, Ivan,Fontanive, Giampaolo,Fregonese, Massimo,Benedetti, Fabio
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p. 1987 - 1999
(2011/04/25)
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- Electron-deficient aryl β-diketones: Synthesis and novel tautomeric preferences
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Fluorinated aryl β-diketones were prepared using Claisen and electrophilic fluorination methods. The keto-enol and enol-enol tautomerism of these compounds were examined in the solid state, as neat liquids and in polar, aprotic solution by crystallography and spectroscopy. Neat-liquid spectroscopic measurements as well as single crystal X-ray crystallographic results for selected electron-deficient aryl β-diketones suggest a single, chelated cis-enol isomer that is conjugated with the aryl ring. In polar aprotic solvents, nonfluorinated aryl β-diketones equilibrate rapidly from the chelated cis-enol form to a tautomeric mixture of cis-chelated enol and a substantial proportion of the diketone form, trifluoromethylated aryl β-diketones show only limited equilibration from the chelated cis-enol to the diketone form, with 2-fluoro-1-aryl β-diketones again displaying only the diketonic form.
- Sloop, Joseph C.,Boyle, Paul D.,Fountain, Augustus W.,Pearman, William F.,Swann, Jacob A.
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experimental part
p. 936 - 941
(2011/04/17)
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- High-yielding oxidation of β-hydroxyketones to β-diketones using o-Iodoxybenzoic acid
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The oxidation of β-hydroxyketones to β-diketones was systematically investigated. o-Iodoxybenzoic acid (IBX) was found to be efficient, operationally easy, and superior to other common oxidants. The reaction is suitable for milligram- to gram-scale oxidations.
- Bartlett, Samuel L.,Beaudry, Christopher M.
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experimental part
p. 9852 - 9855
(2012/01/02)
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- Highly efficient indium(III)-mediated cyclisation of 5-hydroxy-1,3- diketones to 2,3-dihydro-4H-pyran-4-ones; Mechanistic insights from in situ Fourier transform infrared spectroscopy
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5-Hydroxy-1,3-diketones have been synthesised in a facile one-pot reaction from the treatment of acid chlorides with non-substituted ketones and LiHMDS. Subsequent cyclisation to 2,3-dihydro-4H-pyran-4-ones occurs rapidly and in high yield (89-99%) when mediated by anhydrous indium(iii) chloride. A spectroscopic study of the reaction using in situ Fourier transform infrared (FTIR) spectroscopy has shown the reaction to be highly dependent on temperature, metal complex formation and InCl3 concentration. Since the reaction is deactivated by the precipitation of [InCl3·(H 2O)3], the concurrent use of a stronger drying agent, such as molecular sieves 4 A or anhydrous MgSO4, allows the reaction to be successfully carried out at relatively low loadings of InCl 3 (1-10%). In their absence, the optimum reaction conditions were found to be a diketone:InCl3 ratio of 3:1 in toluene, and a reaction temperature of 80 °C.
- Andrews, Philip C.,Gee, William J.,Junk, Peter C.,Krautscheid, Harald
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supporting information; experimental part
p. 698 - 705
(2010/05/11)
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- Seebach's oxazolidinone is a good catalyst for aldol reactions
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Seebach's proline-derived oxazolidinone 2d overcomes (S)-proline and is at least as efficient as (S)-5-(pyrrolidin-2-yl)tetrazole in several organocatalytic aldol reactions examined. A quick exchange takes place between 2d and carbonyl compounds that gives new bicyclic oxazolidinones, in equilibrium with the very minor active species (enamines). Maximum yields of the aldols (β-hydroxy ketones) were achieved after 1-4 h when, with proline, they are attained after 30-48 h.
- Isart, Carles,Burés, Jordi,Vilarrasa, Jaume
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p. 5414 - 5418
(2008/12/22)
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- The first example of molecularly imprinted nanogels with aldolase type I activity
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The molecular-imprinting approach was used to obtain a nanogel preparation capable of catalysing the cross-aldol reaction between 4-nitrobenzaldehyde and acetone. A polymerisable proline derivative was used as the functional monomer to mimic the enamine-b
- Carboni, Davide,Flavin, Kevin,Servant, Ania,Gouverneur, Veronique,Resmini, Marina
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experimental part
p. 7059 - 7065
(2009/08/12)
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- Proline-catalyzed aldol reactions of acyl cyanides with acetone: An efficient and convenient synthesis of 1,3-diketones
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The aldol-type addition of acetone towards (un)substituted benzoyl, heteroarylcarbonyl or α,β-unsaturated acyl cyanides was efficiently catalyzed by l-proline (30 mol %) to give 2-hydroxy-4-oxo-2-substituted pentanenitriles. Upon the treatment with sodium hydroxide, the adducts transformed to 1,3-diketones in good-to-excellent yield, furnishing an efficient and convenient method for the regioselective synthesis of 1,3-diketones.
- Shen, Zongxuan,Li, Bin,Wang, Lu,Zhang, Yawen
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p. 8785 - 8788
(2007/10/03)
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- Evaluation of TCS/ZnCl2 with acetic anhydride as an acetylating reagent for methylene ketones
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A new route for the preparation of β-diketones which have applications in organic synthesis by the reaction of methylene ketones, acetic anhydride, TCS and ZnCl2 in the solvent methylene chloride at room temperature produces the corresponding β-diketones in excellent yield. Copyright Taylor & Francis Inc.
- Elmorsy, Saad S.,Badawy, Doria S.,Khatab, Tamer K.
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p. 109 - 116
(2007/10/03)
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- Group transfer reactions using benzimidazolides
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Transfer of aroyl group from N-aroylbenzimidazoles 1a-d to the enolates generated from ethyl acetoacetate 2 and acetylacetone 3 has been achieved successfully. in-situ Cleavage of acetyl group of the acetylated products has also been observed.
- Karnik, A. V.,Rane, J. P.
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p. 1191 - 1193
(2007/10/03)
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- 13C NMR Spectroscopic Study of the Tautomeric Equilibrium in p-Phenyl Substituted Benzoylacetones
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Solution 13C NMR chemical shifts are reported for a series of p-phenyl substituted benzoylacetones which undergo a fast, intramolecular proton-transfer reaction between both possible enol tautomers.This information, together with 13C NMR spectroscopic data for related non-exchanging model compounds, allows the study of substituent-induced equilibrium shifts.The results show a systematic trend: electron-withdrawing para groups shift the equilibrium towards the methyl keto form.
- Cravero, Raquel M.,Gonzalez-Sierra, Manuel,Olivieri, Alejandro C.
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p. 1067 - 1071
(2007/10/02)
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- An improved synthesis of 2-diazo-1,3-diketones
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The sodium hydride/dibenzo-18-crown-6 ether system was found to be an effective base for the synthesis of 1,3-diketones by the Claisen condensation. The use of potassium fluoride (with or without crown ether) as the base in diazo-transfer reactions extends this reaction to the synthesis of hindered diazo diketones. In the case of isomeric 1,3-diketones, the stereoselectivity of the process considerably rises.
- Popic,Korneev,Nikolaev,Korobitsyna
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p. 195 - 198
(2007/10/02)
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