نتایج جستجو برای: catalyst free
تعداد نتایج: 553796 فیلتر نتایج به سال:
A novel and green approach for efficient and rapid synthesis of biologically active polyhydroquinoline derivatives via unsymmetric Hantzsch reaction using nanorods Vanadatesulfuric acid (VSA NRs) as a new and recyclable catalyst under solvent-free conditions was reported. The catalyst was characterized by FT-IR, XRD, XRF and TEM analysis. The present method offers several advantages such as sim...
A green methodology for the development of the synthesis of dihydropyrimidinones via a clean multi-component Biginelli reaction by using cyclohexane-1,4-diyl bis (hydrogen sulfate) (CDBH) as an effective catalyst in water and solvent-free conditions was reported. This sulfonated catalyst is an efficient and environmentally benign homogeneous catalysts which characterized by using different tech...
An efficient and environmental-friendly synthetic route to 1,8-dioxodecahydroacridines derivatives have been developed via multi-component one-pot Hantzsch reaction of various aldehydes and ammonium acetate with 2 equivalents dimedone in the presence of Phosphorus pentoxide supported on aluminaas catalyst under solvent-free conditions. The present approach offersseveral advantages such as short...
Freshly prepared ZnO nanoparticles were used as an effective heterogeneous base catalyst for the synthesis of aryloximes. The conversion of arylaldehydes and arylketones into the corresponding oximes (up to quantitative yields) was achieved by simply mixing the liquid reactants and hydroxylamine hydrochloride with ZnO nanoparticles under solvent-free condition. The procedure was carried out und...
An efficient synthesis route to 1,4-dihydropyrimidine derivatives from reaction of divergent aldehydes with ethylacetoacetate and urea under solvent-free conditions by ZnO nanoparticles as a relative in expansive, eco-friendly, easy available, non-volatile, non-explosion, thermally robust, recyclable and easy to handle catalyst at 90°C with excellent yields is described. Unenhanced reaction tim...
An efficient synthesis route to 1,4-dihydropyrimidine derivatives from reaction of divergent aldehydes with ethylacetoacetate and urea under solvent-free conditions by ZnO nanoparticles as a relative in expansive, eco-friendly, easy available, non-volatile, non-explosion, thermally robust, recyclable and easy to handle catalyst at 90°C with excellent yields is described. Unenhanced reaction tim...
Summarization of electronic discussion fora is a unique challenge; techniques that work startlingly well on monolithic documents tend to fare poorly in this informal setting. Additionally, conventional techniques ignore much of the structures that have the potential to serve as valuable features in the summarization task. We present several novel examples of such features, including the catalys...
Cellulose sulfuric acid is an efficient metal-free catalyst for the synthesis of 1,3,5-trisubstituted pyrazoles via the condensation of 1,3-diketones and hydrazines. The reaction was carried out in Solvent-free condition at room temperature and the products were isolated in good to excellent yields. Mild reaction conditions, as well as ease of operation and workup are some advantages of the pro...
A DFT investigation into the mechanism for the decomposition of Grubbs 2nd generation pre-catalyst (2) in the presence of methanol, is presented. Gibbs free energy profiles for decomposition of the pre-catalyst (2) via two possible mechanisms were computed. We predict that decomposition following tricyclohexylphosphane dissociation is most favoured compared to direct decomposition of the pre-ca...
this study introduces a green and efficient method for preparation of biologically-active substituted 4h-pyrans using the one-pot three-component reaction of aromatic aldehydes, dimedone and malononitrile in the presence of cobalt oxide nanoparticles. co3o4 nanoparticles were used as an efficient catalyst for the synthesis of polyhydroquinoline derivatives by the reaction of aromatic aldehydes,...
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