نتایج جستجو برای: multi component reactions
تعداد نتایج: 1195877 فیلتر نتایج به سال:
Ab initio and DFT calculations reveal that oxyacyl radicals add to imines and electron-rich olefins through simultaneous SOMO-pi*, SOMO-pi and pi*-HOMO interactions between the radical and the radicalophile. At the BHandHLYP/aug-cc-pVDZ level, energy barriers of 20.3 and 22.0 kJ mol(-1) are calculated for the attack of methoxycarbonyl radical at the carbon and nitrogen ends of methanimine, resp...
alkali and alkaline earth metals hydrogen sulfate catalyzed the one-pot three component condensation reactions of aldehydes, 1,3-dicarbonyl compounds and urea or thiourea under solvent-free conditions leading to 3,4-dihydropyrimidin-2(1h)-ones in high yields at 80 °c. our results showed that biginelli reaction not only is ph dependent, but the cation of catalyst plays an important role.
microwave-assisted three component cyclocondensation reactions of aldehydes, amides and dienophiles in the presence of acetic anhydride and para-toluenesulfonic acid as a catalyst to afford the highly substituted cyclohexene derivatives, in relatively good yields after several minutes are reported.
An Fe3O4-graphene oxide nanocomposite has been synthesized via a chemical reaction with a magnetite particle size of 18-25 nm. The resulting nanocomposite can be easily manipulated by an external magnetic field, exhibits excellent catalytic activity and may be reused for several cycles with marginal loss of activity. This recyclable nanocomposite provides an efficient, economic, novel route for...
an efficient synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles by one-step condensation of an aldehyde, benzil, ammonium acetate and primary amine in the presence of nanocrystalline magnesium aluminate under microwave irradiation is described. the advantages of this catalyst are including simple work-up, low cost and reusability. compared with conventional methods, the ...
Background: Despite global interest, the development of single step processes for the preparation of effective drug delivery systems still faces numerous challenges. There is great demand for processing methods that are efficient, flexible, scalable and economical for the generation of wide range of encapsulated structures. Over the past few decades, electrohydrodynamic (EHD) processing has rec...
Multi-component nucleotide acid enzymes (MNAzymes) derived from RNase-mimic DNAzymes have potential as simple and accurate DNA detectors. To enhance the MNAzyme activity under multiple-turnover conditions, a cationic comb-type copolymer, PLL-g-Dex, that facilitates hybridization and strand exchange reactions of DNA was utilized. The copolymer increased the MNAzyme reaction rate by 200 times, al...
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