نتایج جستجو برای: biginelli type products conditions
تعداد نتایج: 2321328 فیلتر نتایج به سال:
the chemistry of 2-oxo-1,2,3,4-tetrahydropyrimidines began to develop toward the end of 1893 year, when the first representatives of this class compounds were reported by p. biginelli. despite prior reports of several really effective catalytic and non-catalytic approaches towards biginelli-type products, an overwhelming number of new catalysts for the biginelli reaction have been recently publ...
The chemistry of 2-oxo-1,2,3,4-tetrahydropyrimidines began to develop toward the end of 1893 year, when the first representatives of this class compounds were reported by P. Biginelli. Despite prior reports of several really effective catalytic and non-catalytic approaches towards Biginelli-type products, an overwhelming number of new catalysts for the Biginelli reaction have been recently publ...
this study investigated the effects of planning on second-language written production with regard to task type. the participants were 75 iranian learners of english as a foreign language attending a private foreign language institution. they were asked to complete two different types of writing tasks (expository writing task and argumentative writing task) in different planned conditions (indiv...
with the increasing population and the need for more food, as well as with the development of science and technology, human approach to unnatural and often chemical inputs to increase agricultural production has been a great expansion and problems such as increased cancers, chronic diseases has created environmental pollution. implementation of organic organic is a solution to these problems . ...
Various Biginelli compounds (dihydropyrimidinones) have been synthesized efficiently and in high yields under mild, solvent-free, and eco-friendly conditions in a one-pot reaction of 1,3-dicarbonyl compounds, aldehydes, and urea/thiourea/acetyl thiourea using lithium-acetate as a novel catalyst without the addition of any proton source. Comparative catalytic efficiency of lithium-acetate and po...
Simple and improved conditions have been found to carry out the Biginelli reaction for the synthesis of 3, 4-dihydropyrimidin-2(1H) - one derivatives. This synthesis was performed in the presence of 12-molybdophosphoric acid (H3PMo12O40) as catalyst. These reactions were performed under solvent free conditions with microwave irradiation as the energy source. Compared with the classical Biginell...
3,4-dihydropyrimidinones and their derivatives are synthesized via biginelli routes involving an aromatic aldehydes, ethylacetoacetates and urea in one-pot procedure by using cds nanoparticles as efficient heterogeneous catalyst in solvent-free conditions. compared with classical biginelli reaction reported in 1893, this new method provides much improved modification in terms of simplicity. the...
The Biginelli reaction, which is a three-component reaction for the synthesis of dihydropyrimidinone and corresponding dihydropyrimidinethiones (DHPMs) is known for more than a century. A large number researchers have shown consistent attention towards the study of Biginelli reaction, leading towards structurally diversified molecular libraries of DHPMs and it’s analogues, having significant bi...
in this thesis, a better reaction conditions for the synthesis of spirobarbiturates catalyzed by task-specific ionic liquid (2-hydroxy-n-(2-hydroxyethyl)-n,n-dimethylethanaminium formate), calcium hypochlorite ca(ocl)2 or n-bromosuccinimide (nbs) in the presence of water at room temperature by ultrasonic technique is provided. the design and synthesis of spirocycles is a challenging task becaus...
molybdate sulfuric acid (msa) has been prepared and used as catalyst for the biginelli synthesis of some quinazolinones/thiones under solvent-free conditions. the catalyst loading is low and it shows recyclability. this method has advantages such as avoidance of the organic solvents, high yield of pure products, short reaction times and operational simplicity.
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