نتایج جستجو برای: pot reaction
تعداد نتایج: 423614 فیلتر نتایج به سال:
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...
Pot-in-pot reactions are designed such that two reaction media (solvents, catalysts and reagents) are isolated from each other by a polymeric membrane similar to matryoshka dolls (Russian nesting dolls). The first reaction is allowed to progress to completion before triggering the second reaction in which all necessary solvents, reactants, or catalysts are placed except for the starting reagent...
an efficient synthesis of polyhydroquinoline derivatives was reported via four-component coupling reactions of aldehydes, 1,3-dicarbonyl ketones (dimedone or 1,3-cyclohexanedione), ethyl acetoacetate or methyl acetoacetate and ammonium acetate in the presence of a catalytic amount of nanocrystalline tio2 under solvent free conditions. the reported method is mild, rapid and has the advantages su...
nano tio2 supported on sio2 (nano tio2@sio2) as a solid lewis acid, was described to be an effective and reusable catalyst for one-pot three-component reaction of benzil, aryl aldehydes and ammonium acetate for the synthesis 2-aryl-4,5-diphenyl-1h-imdazoles synthesis. to explore the high efficacy of the catalytic system the four-component cyclization of benzil, aryl aldehydes, ammonium acetate ...
in the present study, some new bis-imidazole derivatives have been prepared through four-components condensation of 2,6-bis (4-aminophenyl)-4-p-tolylpyridine, benzaldehyde derivatives, benzil and ammonium acetate in presence of acetic acid. the present methodology offers several advantages such as good yields, simple procedure, milder conditions and the possibility of introducing a variety of s...
in this study, the synthesis of 4 h -chromenes of biological activity via a multicomponent reaction of dimedone, aromatic aldehydes and malononitrile catalyzed by glutamic acid as a catalyst was investigated. the structural features of the synthesized compounds were characterized by melting point, ir and 1 h nmr analysis. the catalyst being reported here is cheap, safe to handle and the whole p...
The one-pot synthesis of a target molecule in the same reaction vessel is widely considered to be an efficient approach in synthetic organic chemistry. In this review, the characteristics and limitations of various one-pot syntheses of biologically active molecules are explained, primarily involving organocatalytic methods as key tactics. Besides catalysis, the pot-economy concepts presented he...
mgo nanopartticels (np-mgo) in average size between 30—130 nm were prepared by sonochemistry method. some phenols have been converted to ortho-hydroxybezaldehyd by ortho-formylation using mgo nanoparticles and (ch2o)n in xylene and subsequently treated with aqueous nh2oh.hcl, affording the corresponding aldoxime in a one-pot procedure. moreover, this one-pot process, with two transformations, o...
a simple and green chemical procedure was reported for the synthesis of dihydropyrimidinones from various aldehydes, ethyl acetoacetate and urea or thiourea using holmium chloride as catalyst. the reactions were performed under solvent free conditions with ultrasound irradiation as the energy source. the advantages of this protocol include the excellent yield, operational simplicity, short tim...
Phosphosulfonic acid (PSA) was found to be an efficient catalyst for the one-pot three-component Hantzsch condensation reaction of arylaldehydes, ethylacetoacetate and ammonium acetate to afford the corresponding 1,4-dihydropyridine and polyhydroquinoline derivatives in high yields. PSA was also applied for the one-pot preparation of polyhydroquinolines via four-component reaction of a...
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