نتایج جستجو برای: up synthesis
تعداد نتایج: 1312991 فیلتر نتایج به سال:
The use of a recyclable phase transfer catalyst, SiO2-PEG-ImBr, is demonstrated in a simple and highly efficient synthesis of phenacyl derivatives by nucleophilic substitution reaction of phenacyl halides with different anions in water. Advantages of this system are easy work-up, moderate to good yields, and recyclable catalyst. The catalyst can be recycled and reused several times with no loss...
1,3-Dibromo-5,5-dimethylhydantoin (DBH), as a cheap and commercially available reagent, is efficiently able to catalyze the synthesis of polyhydroquinoline derivatives and 12-aryl-8,9,10,12-tetrahydro[a] xanthene-11-ones via one-pot multi-component reactions. This novel synthetic method has the advantages of low cost and availability of the catalyst, short reaction times, high to excellent yiel...
TiCl4/nano-cellulose as a biodegradable and eco-friendly Lewis acid catalyst was synthesized via reaction of nano-cellulose and TiCl4. This catalyst was characterized and used for synthesis of asymmetric highly functionalized tetrahydropyridines via a five-component condensation reaction of p-substituted anilines, aldehydes and ethyl acetoacetate under solvent-free condition. Simple methodology...
1,3-Dibromo-5,5-dimethylhydantoin (DBH), as a cheap and commercially available reagent, is efficiently able to catalyze the synthesis of polyhydroquinoline derivatives and 12-aryl-8,9,10,12-tetrahydro[a] xanthene-11-ones via one-pot multi-component reactions. This novel synthetic method has the advantages of low cost and availability of the catalyst, short reaction times, high to excellent yiel...
A simple and environmentally benign procedure for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes by a one-pot condensation of 2-naphthol with aromatic aldehyde in the presence of [Et3NH][HSO4] as an acidic ionic liquid catalyst under solvent-free conditions has been developed. The reaction work-up is very simple and the catalyst can be easily separated from the reaction mixture and reused s...
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...
An efficient one-pot four-component protocol for the synthesis of pyrano[2,3-c]pyrazolederivatives has been demonstrated using Y(NO3)3.6H2O as catalyst under mild condition. This isa general synthetic protocol which could be applicable to a wide range of carbonyl compoundsincluding aromatic aldehydes, isatins and acenaphthenequinone. All The reactions proceededsmoothly, ...
In this investigation, Nano silica chloride (nano SiO2Cl) has been found to be efficient, chemoselective and recyclable catalyst for facile and simple synthesis of germinal diacetates from aromatic and heteroaromatic aldehydes in shorter reaction durations. The products were obtained in high to excellent yields. This work consistently has the advantages of excellent yields, short reaction time,...
An efficient and simple procedure for the synthesis of 1,8-dioxo-octahydroxanthenes from the aromatic aldehydes and 5,5-dimethylcyclohexane-1,3-dione (dimedone) in the presence of boric acid [BO3H3 or B(OH)3] as an inexpensive and reusable catalyst is described. The salient features of this methodology are: the elimination of corrosive liquid acids, high yields, simple methodology, short reacti...
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...
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