نتایج جستجو برای: ring opeing of epoxides
تعداد نتایج: 21176018 فیلتر نتایج به سال:
The minute amount of hydrogen sulfate groups introduced into the graphene oxide (GO) obtained by Hummers oxidation of graphite renders this material as a highly efficient, recyclable acid catalyst for the ring opening of epoxides with methanol and other primary alcohols as nucleophile and solvent.
We report the alternating ring-opening copolymerization of dihydrocoumarin with epoxides catalyzed by chromium(III) salen complexes. This process provides access to a range of perfectly alternating polyesters with high molecular weights and narrow molecular weight distributions. Atactic poly(cyclohexene dihydrocoumarate) and poly(cyclopentene dihydrocoumarate) were found to be semi-crystalline ...
A rational approach towards the borylative ring-opening of vinylepoxides and vinylaziridines, by the in situ formed MeO(-)→bis(pinacolato)diboron adduct, has been developed. The enhanced nucleophilic character of the Bpin (sp(2)) moiety from the reagent favours the SN2' conjugated B addition with the concomitant opening of the epoxide and aziridine rings. The reaction proceeds with total chemos...
The present study, for the first time, presents a feasible protocol for the preparation of β-cyclodextrin/ imidazolium based dicationic ionic liquid, [βCD/Im](OTs)2, and its application as an efficient and eco-friendly microvessel and host ionic liquid system for the regioselective ring opening of the epoxides in water. No evidence for the formation of diol by-products or side reacti...
The synthesis, characterization and crystal structures of copper complexes with chelate ligation derived from the compound 2.2′-diphenylglycine (DpgH) are reported. Compounds [CuCl(Dpg)(EtOH)]2 ( 1 ) [(CuBr2)2(Dpg)2Cu(EtOH)4] 2 were found to be low toxicity using against cancerous cell lines (HCT116 HT29) IC50 values for complex lower than that cisplatin, while opposite was observed . These ina...
The present study, for the first time, presents a feasible protocol for the preparation of β-cyclodextrin/ imidazolium based dicationic ionic liquid, [βCD/Im](OTs)2, and its application as an efficient and eco-friendly microvessel and host ionic liquid system for the regioselective ring opening of the epoxides in water. No evidence for the formation of diol by-products or side reacti...
in this research we have studied the effect of some transition-metals (cu, ag and au) substitutions on two-electron reduction potential of flavins by application of dft method. all geometries have been optimized at blyp level of theory and “6-31+g** + lanl2dz” mixed basis set. the frequency job at the same method and basis sets has been performed to obtain gibbs free energy of compounds. it h...
Biodegradable polymers are a promising sustainable alternative to conventional petroleum-based and have attracted recent extensive research interest due their potential environmental friendliness sustainability. Among them, aliphatic polyesters polycarbonates the most extensively studied ones. The metal-catalyzed ring-opening polymerization (ROP) of cyclic esters copolymerization (ROCOP) epoxid...
The conformational analysis of five β-chloroand β-bromo-alkoxides had been done. The minima and the conformational transition states were determined. The anti conformer was found to be the most stable one. Its percentage is more than 99. α-Methylation increases the nuclophilicity of oxygen .Consequently, it enhances the rate of the ring closure. In contrast to βmethylation which retards the rat...
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