- Ionic liquid-regulated sulfamic acid: Chemoselective catalyst for the transesterification of β-ketoesters
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1-Propyl-3-methylimidazolium chloride ([C3MIm]Cl) ionic liquid and sulfamic acid (NH2SO3H), as a synergetic catalytic medium, were used for the transesterification of acetoacetate with alcohols of different structures. It shows the good ability for the chemoselective transesterificatin of β-ketoesters and maintains its catalytic activity in the reuse.
- Bo, Wang,Ming, Yang Li,Shuan, Suo Ji
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- Prussian blue as an efficient catalyst for rate accelerations in the transesterification of β-ketoesters
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Prussian blue triggered transesterification of ethylacetoacetate with various alcohols underwent efficiently. The reaction is mild, eco-friendly, and selective with good yields. The proposed reaction pathway depicts the formation of an intermediate by the interaction of β-ketoesters with catalytic site of the Prussian blue, followed by nucleophilic attack of the alcohol at the electrophilic center followed by successive elimination of the proton to give the product. Observed longer reaction times under conventional conditions reduced amazingly under sonication and microwave irradiation followed enhanced yield of products.
- Srinivas,Rajanna,Krishnaiah,Kumar, M. Satish,Reddy, J. Narender
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- Zinc mediated transesterification of β-ketoesters and coumarin synthesis
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The transesterification of ketoesters using zinc and iodine is described. The reaction has been done on a variety of alcohols and phenols. Alcohols furnish transesterified products whereas phenols gave 4-methylcoumarins. The method is highly promising compared with existing methods.
- Chavan, Subhash P,Shivasankar,Sivappa,Kale, Ramesh
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- Boric acid: an efficient and environmentally benign catalyst for transesterification of ethyl acetoacetate
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An efficient and environmentally benign boric acid catalyzed protocol for the transesterification of ethyl acetoacetate with a variety of primary and secondary alcohols in good to excellent yields is described. The versatility of this transformation is demonstrated with problematic substrates such as propargyl alcohol and allyl alcohol, which are known to undergo Carroll rearrangement during transesterification.
- Kondaiah,Reddy, L. Amarnath,Babu, K. Srihari,Gurav,Huge,Bandichhor,Reddy, P. Pratap,Bhattacharya,Anand, R. Vijaya
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- Niobium(V) oxide: A new and efficient catalyst for the transesterification of β-keto esters
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Niobium(V) oxide is an efficient catalyst for the transesterification of β-keto esters with several kinds of alcohols, leading to good conversions. Moderate to good isolated product yields have been obtained at faster rates than those recently reported for various catalysts.
- De Sairre, Mirela Inês,Bronze-Uhle, érika Soares,Donate, Paulo Marcos
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- Mo-ZrO2 solid acid catalyst for transesterification of β-ketoesters
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An efficient and mild method for transesterification of β-ketoester catalyzed by Mo-ZrO2 solid acid catalyst is described.
- Reddy, Benjaram M.,Reddy, Vangala R.,Manohar, Basude
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- BF3OEt2: An efficient catalyst for transesterification of β-ketoesters
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A facile and selective transesterification of β-ketoesters using BF3OEt2 as catalyst is described. The emphasis has been placed on the reaction of methyl acetoacetate with a series of alcohols of different structures, leading in all cases to good to excellent yields.
- Yang, Jinhui,Ji, Congbin,Zhao, Yanmin,Li, Yunfeng,Jiang, Shizhi,Zhang, Zhiwei,Ji, Yongqiang,Liu, Wanyi
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- Copper-catalyzed radical coupling of 1,3-dicarbonyl compounds with terminal alkenes for the synthesis of tetracarbonyl compounds
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A novel and efficient copper-catalyzed radical cross-coupling of 1,3-dicarbonyl compounds with terminal alkenes for the synthesis of tetracarbonyl compounds with a quaternary carbon atom has been developed. Mechanistically, this transformation involves the construction of two C-C bonds and two CO bonds in a one-pot process. The reaction tolerates a wide range of functional groups and proceeds under mild conditions.
- Zhang, Mei-Na,Zhao, Mi-Na,Chen, Ming,Ren, Zhi-Hui,Wang, Yao-Yu,Guan, Zheng-Hui
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- Visible-light-driven radical 1,3-addition of selenosulfonates to vinyldiazo compounds
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Herein, we report a visible-light-driven radical 1,3-selenosulfonylation of vinyldiazo compounds with selenosulfonates, providing various γ-seleno allylic sulfones in good yields. This photochemical reaction was carried out at room temperature in an open flask using ethyl acetate as the solvent without any photocatalysts or additives. The control experiments corroborated that the 1,3-addition proceeded via a radical-chain propagation process. The synthetic applications of the resulting products were demonstrated by deselenization, reduction, bromination and allylation.
- Li, Weiyu,Zhou, Lei
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supporting information
p. 6652 - 6658
(2021/09/10)
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- N, N’-dimethyl formamide (DMF) mediated Vilsmeier–Haack adducts with 1,3,5-triazine compounds as efficient catalysts for the transesterification of β-ketoesters
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N, N’-dimethyl formamide (DMF) mediated Vilsmeier–Haack (VH) adducts with 1,3,5-triazine compunds such as trichloroisocyanuric acid (TCCA) and trichlorotriazine (TCTA) were prepared by replacing classical oxy chlorides POCl3, and SOCl2, which were explored as efficient catalysts for the transesterification of β-ketoesters. The prepared (TCCA/DMF) and (TCTA/DMF) adducts improved greenery of the classical Vilsmeier–Haack reagents (POCl3/DMF), and (SOCl2/DMF), and demonstrated their better efficient catalytic ativity. Reaction times were in the range: 3.5 to 6.5 hr (SOCl2/DMF); 2.8–5.2 hr (POCl3/DMF); 2.5–5.2 hr (TCCA/DMF) and 2.5–5.0 hr (TCTA/DMF) catalytic systems. Ultrasonically (US) assisted protocols with these reagents further reduced the reaction times (two to three times), while microwave assisted (MW) protocols with these reagents were much more effective. The reactions could be completed in only few seconds (less than a minute) in MWassisted protocols as compared to US assited reactions, followed by good product yields.
- Chityala, Yadaiah,Duguta, Govardhan,Kamatala, Chinna Rajanna,Muddam, Bhooshan,Mukka, Satish Kumar
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supporting information
p. 1641 - 1655
(2020/05/25)
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- Ag-Cu nanoparticles as efficient catalysts for transesterification of β-keto esters under acid/base-free conditions
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Transesterification of β-keto esters and alcohols are traditionally catalyzed by acid or basic catalysts. However, these traditional catalysts do not always meet the requirements of modern synthetic chemistry which need to be highly efficient, selective, and environmentally friendly. In this work, Ag-Cu metal sites were first introduced as transesterification catalysts. The effect of the support, Ag:Cu molar ratio, and reaction conditions were investigated. The Ag-Cu metal sites were proved to be active in the β-ketoester transesterification with various alcohols, having yields comparable to the conventional acid- or base-catalysts.
- Yue, Hongmei,Yu, Hao,Liu, Sheng,Xu, Chunli
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p. 19041 - 19051
(2016/03/01)
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- 3, 4, 5-tri-substituted oxazolidinone compounds and its preparation method (by machine translation)
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The invention discloses a formula (I) of the structure shown in the 3, 4, 5? Tri-substituted oxazolidinone compound preparation method, the preparation method comprises: in the organic solvent, like type compound of the structure shown in the (II), of the structure shown in the formula (III) compound, organic base and the contact reaction mixture CuI, wherein R1 is selected from H, C1? C6 alkyl or nitro, R2 is selected from H or C1? C6 alkyl, R3 is selected from H, C1? C10 alkyl or vinyl. The steps of the preparation method is simple, is easy to obtain raw materials and catalyst, mild reaction conditions and high yield, (by machine translation)
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Paragraph 0043-0045
(2017/04/05)
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- An efficient synthesis of β-ketoesters via transesterification and its application in Biginelli reaction under solvent-free, catalyst-free conditions
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A simple and efficient transesterification process for the synthesis of β-ketoester derivatives has been achieved by the reaction of methyl β-ketoester with higher alcohols at 110 C under solvent-free, catalyst-free conditions and its application in synthesis of 3,4-dihydropyrimidin-2(1H)-ones C-5 ester derivatives via Biginelli reaction has been described.
- Dharma Rao,Acharya,Kaushik
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supporting information
p. 6644 - 6647
(2013/11/19)
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- Efficient trans-acetoacylation mediated by ytterbium(III) triflate as a catalyst under solvent-free condition
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A simple and efficient trans-acetoacylation method for the synthesis of β-keto ester derivatives has been described using ytterbium(III) triflate as a new catalyst under solvent-free condition. This method was found to be efficient and convenient for the synthesis of a wide variety of β-keto ester derivatives.
- Dharma Rao,Kaushik
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experimental part
p. 5104 - 5106
(2011/10/08)
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- Microwave-assisted solution-phase synthesis of 1,4,5-trisubstituted pyrazoles
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A small parallel library of 1,4,5-trisubstituted pyrazoles was prepared in solution using a three-step procedure starting from Meldrum acid. The Meldrum acid was acylated with different acyl chlorides and the products opened with different alcohols and amines to give substituted β-keto esters and β-keto amines. Further reaction with N,N-dimethylformamide dimethylacetal and the final cyclisation were effectively carried out under microwave irradiation. Scavenger resins were employed exclusively in the first step, whereas use of microwaves allowed complete conversion of the starting materials in the other two steps. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
- Giacomelli, Giampaolo,Porcheddu, Andrea,Salaris, Margherita,Taddei, Maurizio
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p. 537 - 541
(2007/10/03)
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- Process for the transesterification of keto esters using solid acids as catalysts
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A process for the transesterification of keto esters and alcohols in approximately stoichiometric amounts using a solid acid catalyst. Solid acid catalysts may be sulfated zirconia, sulfated tin oxide, sulfated titania, sulfated iron oxide, heteropoly acids, acidic clays, acidic zeolites, or any other solid acids with high acidity or super acidity, with or without dopants. One equivalent or more of keto ester, one equivalent or more of alcohol, the solid acid catalyst, and an appropriate solvent are mixed and heated to 70 to 120° C. at atmospheric or reduced pressure to furnish the keto transester in high yields.
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- Transesterification of ketoesters using Amberlyst-15
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A facile one-to-one transesterification of ketoesters by Amberlyst-15 is described.
- Chavan,Tripura Subbarao,Dantale,Sivappa
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p. 289 - 294
(2007/10/03)
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- Liquid oligomers containing acrylate unsaturation
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The liquid oligomeric compositions of this invention are made by the Michael addition reaction of acetoacetate functional donor compounds with multifunctional acrylate receptor compounds where the equivalent ratios of multifunctional acrylate to acetoacetate vary from >/=1:1 to >/=13.2:1 depending on the functionality of both multifunctional acrylate and acetoacetate. Unuseable gelled or solid oligomer products occur below the claimed ranges. The liquid oligomers of this invention are further crosslinked to make coatings, laminates and adhesives.
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- α-Oxosulfines, IV: Intramolecular hetero diels-alder reactions of α,α′-dioxosulfines - A new access to the [3.3.1]-bicyclic skeleton
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Simple transformations of tert-butylthio-substituted 1,4-oxathiin permitted the preparation of oxathiin S-oxides. These in turn were suitable precursors of corresponding α,α′-dioxosulfine dienes with tethered internal electron-rich double bonds. Examining the synthetic utility of these sulfines, we observed either hydrolysis or intramolecular cycloaddition, depending on the distance between the reactive centres and the substitution on the double bond. Bicyclic derivatives with a [3.3.1] skeleton and an sp2 bridgehead carbon were obtained from the cycloadditions. Wiley-VCH Verlag GmbH, 2000.
- Capozzi, Giuseppe,Menichetti, Stefano,Nativi, Cristina,Provenzani, Alessandro
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p. 3721 - 3725
(2007/10/03)
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- Synthesis of [allyl-2,3-3H]-MN-9201
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Key step of the synthesis of calcium antagonist MN-9201 was the cyclizing addition of the ally-13-amino-crotonate onto methyl 2-[(3- nitrophenyl) methylene ]-3-oxobutanoate. It was then used to synthesize [Allyl-2,3-3H]-MN-9201 by the catalytic addition of tritium gas. Its radiochemical purity and specific activity were 98% and 2.1TBq/mmol, respectively.
- Wu, Dezhu,Huang, Wenlin,Wang, Wen,Mei, Qibing
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p. 785 - 789
(2007/10/03)
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- Selective Catalytic Transesterification, Transthiolesterification, and Protection of Carbonyl Compounds over Natural Kaolinitic Clay
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Transesterification and transthiolesterification of β-keto esters with variety of alcohols and thiols and selective protection of carbonyl functions with various protecting groups catalyzed by natural kaolinitic clay are described. The clay has been found to be an efficient catalyst in transesterifying long chain alcohols, unsaturated alcohols, and phenols to give their corresponding β-keto esters in high yields. For the first time, transthiolesterification of β-keto esters with a variety of thiols has been achieved under catalytic conditions. Clay also catalyzes selective transesterification of β-keto esters by primary alcohols in the presence of secondary and tertiary alcohols giving corresponding β-keto esters. A systematic study involving the reactivity of different nucleophiles (alcohols, amines, and thiols) toward β-keto esters is also described. Sterically hindered carbonyl groups as well as α,β-unsaturated carbonyl groups underwent protection without the deconjugation of the double bond. Chemoselective protection of aldehydes in the presence of ketones has also been achieved over natural kaolinitic clay.
- Ponde, Datta E.,Deshpande, Vishnu H.,Bulbule, Vivek J.,Sudalai, Ammugam,Gajare, Anil S.
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p. 1058 - 1063
(2007/10/03)
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- The synthesis of β-keto lactones via cyclization of β-keto ester dianions or the cyclization of Meldrum's acid derivatives
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Two new methods to synthesize macrocyclic β-keto lactones have been developed.The first involves the synthesis of ω-halo-β-keto esters and an intramolecular alkylation of the dianions to these compounds.The reaction is complicated by elimination in the small and medium ring systems and by difficulties in purifying the final products.However, it is possible to obtain modest yields of the desired β-keto lactones.This procedure was used to synthesize the 25- and 27-membered ring β-hydroxy lactones that are the constituents of termite defense compounds.The second method involves the thermolysis of acylated Meldrum's acid derivatives, which leads directly to β-keto lactones.This process gives modest yields of macrocyclic systems and good yield of the unsubstituted 3-oxopentan-5-olide (25) .The 14-membered macrocyclic β-keto lactone 9j has a complex 1H NMR spectrum, which has been interpreted in terms of multiple conformations.The temperature dependence of the NMR spectrum of 9j is consistent with entropic, rather than enthalpic, control of the equilibrium.Quasiharmonic entropy calculations are consistent with this model.
- Lermer, Leonard,Neeland, Edward G.,Ounsworth, James P.,Sims, Russell J.,Tischler, Samuel A.,Weiler, Larry
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p. 1427 - 1445
(2007/10/02)
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- Calcium channel blocking and positive inotropic activities of ethyl 5-cyano-1,4-dihydro-6-methyl-2-[(phenylsulfonyl)methyl]-4-aryl-3-pyrid ine-carboxylate and analogues. Synthesis and structure-activity relationships
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The synthesis and pharmacological evaluation of a series of 2-[(arylsulfonyl)methyl]-4-aryl-5-cyano-1,4-dihydropyridine-3-carboxyl ic acid esters and analogues are described. These compounds possess a unique profile namely, calcium channel blocking and positive inotropic activities in vitro. Compound 54 was selected as the best compound in the series and was studied in detail. The synthesis and biological profiles of enantiomers of 54 are also reported. The data indicate that although the calcium channel blocking property of 54 is stereospecific the positive inotropic activity is not. Examples of 3- and 6-cyano and other closely related 1,4-dihydropyridine derivatives are described and evaluated for comparison and were found to be devoid of dual activities mentioned above.
- Sircar,Gregor,Anderson,Haleen,Shih,Weishaar,Steffen,Pugsley,Taylor
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p. 2248 - 2260
(2007/10/02)
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- Transacetoacetylation with tert-Butyl Acetoacetate: Synthetic Apllications
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Reaction of various nucleophiles with tert-butyl acetoacetate (t-BAA, 1a) is shown to be a convenient method for the preparation of a wide variety of acetoacetic acid derivatives.This material can be used to prepare acetoacetates and acetoacetamides from a wide variety of alcohols and amines.Reaction of 1a with an unhindered primary amine such as n-heptylamine under standard conditions gives unwanted byproducts due to the formation of the enamines 24 and 25.Formation of these byproducts can be minimized by dilution and/or altering the mode of addition.
- Witzeman, J. Stewart,Nottingham, W. Dell
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p. 1713 - 1718
(2007/10/02)
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- Carbapenem antibiotics
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Disclosed are novel carbapenem derivatives characterized by a 2-substituent of the formula STR1 in which A represents a C1 -C6 straight or branched chain alkylene group; R5 represents an optionally substituted aliphatic, cycloaliphatic, cycloaliphatic-aliphatic, aryl, araliphatic, heteroaryl, heteroaraliphatic, heterocyclyl or heterocyclyl-aliphatic radial and STR2 represents a nitrogen-containing aromatic heterocycle attached to the alkylene group A at a ring carbon atom and quaternized by substituent R5. Such derivatives are useful as potent antibacterial agents.
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- Catalytic Dimerization of Ketene. A Simple and Convenient Method for the Preparation of Diketene and Esters of Acetoacetic Acid
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A new method for the preparation of diketene is described.The main feature of the procedure is the dimerization of ketene in the presence of tetramethylethylenediamine (TMEDA) and the direct use of crude diketene in the syntheses of acetoacetic esters.Keywords: Dimerization of ketene; Tetramethylethylenediamine, catalytic action of
- Jarowicki, Krzysztof,Kwitakowski, Stefan
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p. 141 - 144
(2007/10/02)
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- Esters of phenalkyloxycarbonylamino acids
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Novel esters of phenylalkyloxy- or phenylalkylthioacylamino acids and pyridylalkyloxy- or pyridylalkylthioacylamino acids, synthesis thereof, intermediates therefor, and the use of said esters for the control of weeds.
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- 1,4-Dihydropyridine esters
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A new class of 1,4-dihydropyridines which are characterized by the presence of ester substitutes at positions 3 and 5 of the nucleus and by the presence of an alkoxyalkyl at position 2. The products exhibit coronary activity and have particular application as coronary dilators, antifibrillators, anti-hypertensives, and as muscular and vascular spasmolytics.
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- 1,4-Dihydropyridine carboxylic acid esters useful as coronary vessel dilators and anti-hypertensives
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Certain 1,4-dihydropyridine carboxylic acid esters or their pharmaceutically acceptable non toxic salts are useful as coronary vessel dilators and antihypertensives.
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