- Preparation method of 3-amino-2-butenoic acid cinnamyl ester
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The invention provides a preparation method of 3-amino-2-butenoic acid cinnamyl ester, which comprises the following steps: mixing diketene with cinnamyl alcohol in a dropwise adding manner, and carrying out an esterification reaction to obtain a mixed solution containing acetoacetic acid cinnamyl ester; wherein in the process of dropwise adding the diketene, the temperature of the esterificationreaction is 30-60 DEG C. The preparation method provided by the invention is simple and feasible, the product yield is higher, the intermediate product does not need to be purified, the subsequent reaction can be directly carried out, and the method is suitable for large-scale production.
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Paragraph 0035; 0037-0039; 0042; 0044-0046; 0049; 0051-0053
(2020/12/30)
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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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- Enzymatic Synergism in the Synthesis of β-Keto Esters
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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.
- Wisniewska, Catalina,Koszelewski, Dominik,Zysk, Malgorzata,Klossowski, Szymon,Zdlo, Anna,Brodzka, Anna,Ostaszewski, Ryszard
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p. 5432 - 5437
(2015/08/24)
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- Nano CuFe2O4: An efficient, magnetically separable catalyst for transesterification of β-ketoesters
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The preparation of a variety of β-ketoesters was achieved in high yields from methyl acetoacetate under neutral conditions through the utilization of magnetic CuFe2O4 nanoparticles as catalyst. Recycling of the catalyst was performed up to eight times without significant loss in activity. The catalyst was characterized using XRD, XPS, SEM and TEM techniques.
- Gohain, Mukut,Kumar, Vinod,Van Tonder, Johannes H.,Swart, Hendrik C.,Ntwaeaborwa, Odireleng M.,Bezuidenhoudt, Barend C. B.
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p. 18972 - 18976
(2015/03/04)
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- General and efficient transesterification of β-keto esters with various alcohols using Et3N as a br?nsted base additive
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Transesterification of β-keto esters with a wide variety of allyl, benzyl, propargyl, and alkyl alcohols using, for the first time, commercially available and inexpensive Et3N as a Br?nsted base additive, is efficiently performed in toluene at reflux. The corresponding esters are exclusively obtained in 57-98% yields with no trace amounts of γ,δ-ketones, usually expected from the decarboxylative Carroll rearrangement.
- Mhasni, Olfa,Erray, Imen,Rezgui, Farhat
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p. 3320 - 3327
(2015/10/06)
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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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p. 1212 - 1220
(2014/04/17)
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- Manganese(II) salts as efficient catalysts for chemo selective transesterification of β-keto esters under non-conventional conditions
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Transesterification of β-ketoesters with various alcohols has been studied under conventional and non-conventional conditions using desktop chemicals such as Mn(II) salts as catalysts. These methods offered transesterification of β-ketoesters in good yields with dramatic rate accelerations and reduced reaction times. The developed protocols under nonconventional methods such as sonication and microwave irradiation are highly promising compared with the existing procedures.
- Krishnaiah,Sandeep,Kondhare,Rajanna,Narendar Reddy,Rajeshwar Rao,Zhubaidha
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p. 703 - 706
(2013/02/23)
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- AgOTf-catalyzed transesterification of β-keto esters
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AgOTf proved to be an effective catalyst for the transesterification of β-keto esters with primary, secondary and tertiary alcohols. The products were obtained in high yield within a reasonable reaction time period. The kinetics of the transesterification reaction were also studied and the reaction was found to follow second-order kinetics. Copyright
- Das, Rima,Chakraborty, Debashis
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experimental part
p. 140 - 144
(2012/05/20)
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- Lewis acid/CpRu dual catalysis in the enantioselective decarboxylative allylation of ketone enolates
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The addition of a Lewis acidic metal triflate salt Mg(OTf)2 as co-catalyst in the CpRu-catalyzed decarboxylative allylation of in situ-generated ketone enolates allows the reaction to proceed at lower temperature with higher regio- and enantios
- Linder, David,Austeri, Martina,Lacour, Jerome
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supporting information; body text
p. 4057 - 4061
(2009/12/06)
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- Enantioselective CpRu-catalyzed carroll rearrangement - Ligand and metal source importance
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The addition of unstabilized carbonyl nucleophiles to unsymmetrical allyl-metal fragments still represents a challenge to generate stereogenic centers enantio- and regioselectively. In this context, the decarboxylative Carroll rearrangement of allyl β-keto esters is particularly interesting, since chiral γ,δ-unsaturated ketones are obtained. Herein, we show that CpRu half-sandwich complexes can, with selected enantio-pure pyridine-monooxazoline ligands, catalyze this transformation and afford complete conversions along with good levels of regioselectivity and enantioselectivity. Even more challenging (electron-poor) substrates react (up to 86% ee, branched/linear ratio ≥ 97:03). In addition, the use of an air-stable metal precursor, namely [CpRu(η6-naphthalene)][PF6], allows the reaction to be carried out reproducibly even in non-anhydrous THF with a catalyst loading as low as 2 mol-%. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Linder, David,Buron, Frederic,Constant, Samuel,Lacour, Jerome
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supporting information; experimental part
p. 5778 - 5785
(2009/06/18)
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- Metal salts as novel catalysts for efficient transesterification of β-ketoesters
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Ethyl/methyl β-ketoesters with alcohols in presence of catalytic amount of anhydrous metal salts (FeSO4, CuSO4) undergo smooth transesterification.
- Bandgar,Sadavarte,Uppalla
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p. 2063 - 2066
(2007/10/03)
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