نتایج جستجو برای: knoevenagel condensation

تعداد نتایج: 32510  

2011
Chen Zhuo Dong Xian Wu Jian-wei Xie Hui

The Knoevenagel condensation reaction of aldehydes with malononitrile was described in this study, which was catalyzed by an efficient and recyclable ionic liquid-supported proline. The method represented an attractive alternative to the classical synthesis strategies and exhibited the advantage of performing homogeneous chemistry on a large scale additionally avoided large excesses of reagents...

Journal: :Organic & biomolecular chemistry 2015
Carole Guyon Marie-Christine Duclos Marc Sutter Estelle Métay Marc Lemaire

A one-pot two-step reaction (Knoevenagel condensation - reduction of the double bond) has been developed using calcium hydride as a reductant in the presence of a supported noble metal catalyst. The reaction between carbonyl compounds and active methylene compounds such as methylcyanoacetate, 1,3-dimethylbarbituric acid, dimedone and the more challenging dimethylmalonate, affords the correspond...

2009
Shi-Jie Zhang Xian-Ming Zheng Wei-Xiao Hu

The title compound, C(12)H(10)N(2)O(6), was synthesized via a Knoevenagel condensation and crystallized from ethanol. In the crystal, strong classical inter-molecular O-H⋯O hydrogen bonds and weak C-H⋯N contacts link the mol-ecules into ribbons extending along [010]. Intra-molecular O-H⋯O and C-H⋯N contacts support the planar conformation of the mol-ecules (mean deivation 0.0270 Å).

Journal: :Oriental journal of chemistry 2021

Functionalized alkenes were successfully synthesized via a clean procedure in short time by using new recycled heterogeneous catalyst prepared from Moroccan oil shale, this is characterized different technics such XRD, BET-BJH, MEB-EDS, and TGA, before it’s has been used the Knoevenagel condensation between aldehydes active methylenes. The results showed that coupling with ultrasound irradiatio...

2012
Maria Ines Flores-Conde Leonor Reyes Rafael Herrera Hulme Rios Miguel A. Vazquez Rene Miranda Joaquin Tamariz Francisco Delgado

Infrared irradiation promoted the Diels-Alder cycloadditions of exo-2-oxazolidinone dienes 1-3 with the Knoevenagel adducts 4-6, as dienophiles, leading to the synthesis of new 3,5-diphenyltetrahydrobenzo[d]oxazol-2-one derivatives (7, 9, 11 and 13-17), under solvent-free conditions. These cycloadditions were performed with good regio- and stereoselectivity, favoring the para-endo cycloadducts....

Journal: :Beilstein Journal of Organic Chemistry 2007
Dipak Prajapati Kalyan Jyoti Borah

The synthesis of novel fused heterocycles is based on reactions proceeding by the mechanism of the tert-amino effect, which generalizes cyclization of certain derivatives of 3-methyl-1-phenyl-2-pyrazolin-5-ones. Using this strategy a variety of fused heterocycles is obtained by the Knoevenagel condensation of 5-tert-amino-3-methyl-1-phenylpyrazolone-4-carboxal-dehyde 3 with active methylene com...

2018
Snehali Mali Sachin Shinde Shashikant Damte Suresh Patil

Without using any toxic or hazardous reagent, ligand, acid, transition metal catalyst, additives/promoters and organic solvent, green Knoevenagel condensation and tandem Knoevenagel-Michael reactions have been successfully carried out by using chickpea leaf exudates as a naturally sourced Bronsted acid type bio-catalyst. The reaction proceeds in neat chickpea leaf exudates at room temperature i...

Journal: :Molecules 2017
Yanhui Qiao Junjiang Teng Shuangfei Wang Hao Ma

A biomass-based catalyst with amine groups (-NH₂), viz., amine-functionalized sugarcane bagasse (SCB-NH₂), was prepared through the amination of sugarcane bagasse (SCB) in a two-step process. The physicochemical properties of the catalyst were characterized through FT-IR, elemental analysis, XRD, TG, and SEM-EDX techniques, which confirmed the -NH₂ group was grafted onto SCB successfully. The c...

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