40552-84-9Relevant academic research and scientific papers
Ag-Cu nanoparticles as efficient catalysts for transesterification of β-keto esters under acid/base-free conditions
Yue, Hongmei,Yu, Hao,Liu, Sheng,Xu, Chunli
, p. 19041 - 19051 (2016/03/01)
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.
Enzymatic Synergism in the Synthesis of β-Keto Esters
Wisniewska, Catalina,Koszelewski, Dominik,Zysk, Malgorzata,Klossowski, Szymon,Zdlo, Anna,Brodzka, Anna,Ostaszewski, Ryszard
, p. 5432 - 5437 (2015/08/24)
Reaction of alcohols with ethyl and tert-butyl acetoacetate catalyzed by a combination of commercially available enzymes is shown to be a convenient method for the preparation of a range of acetoacetic acid derivatives. Systematic studies proved that the combination of two or more enzymes enhances the yield of the reaction. Application of the selected enzyme mixture for enzymatic transesterification of various β-keto esters provided the respective products in excellent yields up to 96% and quantitative within 24 and 48 hours, respectively. The presented methodology is simple and mild, and can be used to prepare acetoacetates from primary and secondary alcohols. Application of a selected enzyme mixture for enzyme-catalyzed esterification of various carboxylic acids provided the respective β-hydroxy esters in excellent yields up to 96% and quantitative within 24 and 48 hours, respectively.
Process for the transesterification of keto esters using solid acids as catalysts
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, (2008/06/13)
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.
Nucleophilic catalysis with π-bound nitrogen heterocycles: Synthesis of the first ruthenium catalysts and comparison of the reactivity and the enantioselectivity of ruthenium and iron complexes
Garrett, Christine E.,Fu, Gregory C.
, p. 7479 - 7483 (2007/10/03)
Three ruthenium complexes that bear π-bound nitrogen heterocycles have been synthesized. It is established that these complexes serve as effective nucleophilic catalysts for a range of processes, including the acylation of alcohols with diketene, the ring opening of azlactones, and the addition of alcohols to ketenes; their activity is comparable to or somewhat greater than the corresponding iron catalysts. The relative efficiency of die ruthenium complexes as asymmetric catalysts is also evaluated in the kinetic resolution of secondary alcohols, ruthenium is markedly less effective than iron, but in the deracemization/ring opening of azlactones, ruthenium is slightly more enantioselective. This study documents or the first time the impact of the metal on the reactivity and on the enantioselectivity of nucleophilic catalysts based on π-bound nitrogen heterocycles.
Diketene a new esterification reagent in the enzyme-aided synthesis of chiral alcohols and chiral acetoacetic acid esters
Jeromin, Guenter E.
, p. 6663 - 6664 (2007/10/02)
It was found that in the presence of Pseudomonas lipase diketene can be used as a new reagent for irreversible and enantioselective acylation of secondary alcohols. The reagent is useful to prepare optically active alcohols and optically active acetoacetic acid esters.
Yeast-Mediated Resolution of β-Keto Esters of Prochiral Alcohols
Hudlicky, Tomas,Tsunoda, Toshiya,Gadamasetti, Kumar G.,Murry, Jerry A.,Keck, Gary E.
, p. 3619 - 3623 (2007/10/02)
Several racemic alcohols were converted to their β-keto esters with diketene, and the resulting compounds were subjected to kinetic resolution by means of baker's yeast.The unreacted keto esters were separated from the reduced hydroxy esters by chromatography, and the products were analyzed for levels of enantiomeric excess.Chiral shift reagents, Mosher esters, and optical rotation of the enantiomers of the alcohols were the criteria used to determine the optical integrity of the resolved alcohols after hydrolysis of the esters.Absolute sterochemistry was determined for the resolution products of all the substrates.Some rationale is advanced to account for the observed levels of enantiomeric excess and for the apparent diastereospecifity of the enzymatic resolution.The utility of this process as means of resolution of prochiral alcohols as well as an application of such resolution to the preparation of both enantiomers of a pyrrolizidine alkaloid synthon are indicated.
Acetoacetylation with Diketene Catalyzed by 4-Dimethylaminopyridine
Nudelman, Abraham,Kelner, Rachel,Broida, Neomi,Gottlieb, Hugo E.
, p. 387 - 388 (2007/10/02)
A useful procedure for the acetoacetylation of alcohols 1 with diketene 2 to acetoacetic esters 3 is reported.
