2141-62-0Relevant articles and documents
Memory effect of hydrotalcites and its impact on cyanoethylation reaction
Teodorescu,Pǎlǎdu?ǎ,Pavel
, p. 2055 - 2059 (2013)
The aim of this work is to study the changes of hydrotalcites structure when is subjected to gradual multiple calcination/hydration treatments in the presence of water or alkaline solution with the same composition like in co-precipitation step and then to analyze its influence on the catalytic activity in the cyanoethylation reaction between ethanol and acrylonitrile with the main product being beta-ethoxypropionitrile according to these treatment. The samples were characterized by elemental analysis, XRD, DRIFT, CO 2-TPD.
KOtBu-Catalyzed Michael Addition Reactions Under Mild and Solvent-Free Conditions
Thiyagarajan, Subramanian,Krishnakumar, Varadhan,Gunanathan, Chidambaram
supporting information, p. 518 - 523 (2020/02/04)
Designed transition metal complexes predominantly catalyze Michael addition reactions. Inorganic and organic base-catalyzed Michael addition reactions have been reported. However, known base-catalyzed reactions suffer from the requirement of solvents, additives, high pressure and also side-reactions. Herein, we demonstrate a mild and environmentally friendly strategy of readily available KOtBu-catalyzed Michael addition reactions. This simple inorganic base efficiently catalyzes the Michael addition of underexplored acrylonitriles, esters and amides with (oxa-, aza-, and thia-) heteroatom nucleophiles. This catalytic process proceeds under solvent-free conditions and at room temperature. Notably, this protocol offers an easy operational procedure, broad substrate scope with excellent selectivity, reaction scalability and excellent TON (>9900). Preliminary mechanistic studies revealed that the reaction follows an ionic mechanism. Formal synthesis of promazine is demonstrated using this catalytic protocol.
Formation of a New, Strongly Basic Nitrogen Anion by Metal Oxide Modification
Tamura, Masazumi,Kishi, Ryota,Nakayama, Akira,Nakagawa, Yoshinao,Hasegawa, Jun-Ya,Tomishige, Keiichi
, p. 11857 - 11867 (2017/09/08)
Development of new hybrid materials having unique and unprecedented catalytic properties is a challenge for chemists, and heterogeneous-homogeneous hybrid catalysts have attracted much attention because of the preferable and exceptional properties that are highly expected to result from combination of the components. Base catalysts are widely used in organic synthesis as key materials, and a new class of base catalysts has made a large impact from academic and industrial viewpoints. Here, a principle for creating a new strong base by hybridization of homogeneous and heterogeneous components is presented. It is based on the modification of organic compounds with metal oxides by using the acid-base property of metal oxides. Based on kinetic and DFT studies, combination of CeO2 and 2-cyanopyridine drastically enhanced the basicity of 2-cyanopyridine by a factor of about 109 (～9 by pKa (in CH3CN)), and the pKa was estimated to be ～21, which locates it in the superbase category. 2-Cyanopyridine and CeO2 formed a unique adsorption complex via two interaction modes: (i) coordinative interaction between the Ce atom of CeO2 and the N atom of the pyridine ring in 2-cyanopyridine, and (ii) covalent interaction between the surface O atom of CeO2 and the C atom of the CN group in 2-cyanopyridine by addition of the lattice oxygen of CeO2 to the CN group of 2-cyanopyridine. These interactions established a new, strongly basic site of N- over the CeO2 surface.
Oxa-Michael addition promoted by the aqueous sodium carbonate
Guo, Shi-Huan,Xing, Sheng-Zhu,Mao, Shuai,Gao, Ya-Ru,Chen, Wen-Liang,Wang, Yong-Qiang
supporting information, p. 6718 - 6720 (2014/12/11)
An efficient Michael addition of alcohols to activated alkenes promoted by sodium carbonate with water as reaction medium has been developed. The reaction provides a general, economical and environmentally friendly approach for the synthesis of β-alkoxycarbonyl compounds.
