نتایج جستجو برای: ring opeing of epoxides

تعداد نتایج: 21176018  

Journal: :Chemical communications 2012
Amarajothi Dhakshinamoorthy Mercedes Alvaro Patricia Concepción Vicente Fornés Hermenegildo Garcia

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.

Journal: :Chemical communications 2014
Nathan J Van Zee Geoffrey W Coates

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 ...

Journal: :Organic & biomolecular chemistry 2013
Xavier Sanz Graham M Lee Cristina Pubill-Ulldemolins Amadeu Bonet Henrik Gulyás Stephen A Westcott Carles Bo Elena Fernández

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...

Journal: :Polyhedron 2021

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...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1391

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...

Journal: :Science China-chemistry 2022

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...

2011
Mustafa R. Helal

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...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید