نتایج جستجو برای: Ring opening

تعداد نتایج: 167807  

Journal: :nanochemistry research 1999
eshagh rezaee nezhad ezatallah pourmalekshahi

an efficient and simple method for the preparation of si-imidazole-hso4 functionalized magnetic fe3o4 nanoparticles (si-im-hso4 mnps) and used as an efficient and reusable magnetic catalysts for the regioselective ring opening of epoxides under green conditions in water. this catalyst was used for the ring opening of epoxide corresponding to the thiocyanohydrins and azidohydrines. compared to t...

Journal: :nanochemistry research 0
fariborz mansouri chemistry department, tarbiat modares university, tehran, iran mehdi sheykhan chemistry department, guilan university, rasht, iran akbar heydari chemistry department, tarbiat modares university, tehran, iran

a mild, green and highly efficient route for regio-selective amination of oxiranes was developed via incorporation of mn(ii), fe(ii), co(ii), ni(ii), cu(ii) and zn(ii) cations onto the surface of hydroxyapatite-encapsulated γ-fe2o3 nanoparticles (γ-fe2o3@hap). among six magnetically recoverable catalytic systems denoted as [γ-fe2o3@hap-mii], the catalyst in which m designated as fe(ii) showed t...

Journal: :nanochemistry research 0
liu jiesheng school of civil engineering and architecture, wuhan polytechnic university, wuhan, china liu ke school of civil engineering and architecture, wuhan polytechnic university, wuhan, china xue lian wu chang hospital, wuhan, china he xiang school of civil engineering and architecture, wuhan polytechnic university, wuhan, china

polydimethylsiloxane (pdms) has been synthesized by ring-opening polymerization of octamethylcyclotetrasiloxane (d4) in microemulsion with acidic catalyst. the structure and properties of microemulsion were characterized by transmission electron microscopy (tem), fourier transform infrared spectroscopy (ft-ir), photo correlation spectroscopy (pcs). the effect of the variation in ph value, amoun...

Journal: :iranian journal of catalysis 2014
hossein eshghi zaiddodine pashandi gholam hossein rounaghi afsaneh alipour azadeh shafaie

the regioselective ring opening of styrene oxide using elemental iodine and bromine in the presence of disulfides as new catalysts was studied. the conductivity titration and uv spectroscopy were used to study the interaction of iodine with these catalysts. the results indicate that disulfide 11 is efficient in polyiodide formation, and can catalyze this reaction in excellent yield and high reg...

Journal: Nanochemistry Research 2016

An efficient and simple method for the preparation of Si-Imidazole-HSO4 functionalized magnetic Fe3O4 nanoparticles (Si-Im-HSO4 MNPs) and used as an efficient and reusable magnetic catalysts for the regioselective ring opening of epoxides under green conditions in water. This catalyst was used for the ring opening of epoxide corresponding to the thiocyanohydrins and azidohydrines. Compared to t...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2010
jamshid mohammadi-rovshandeh majid abdouss sayed mehdi hoseini mohammad imani kamel ekhlasi-kazaj

in this work, new biodegradable abcba type pentablock copolymers with different mole ratio of l-lactide and ppdo-b-peg-b-ppdo triblock copolymer were synthesized and characterized. in the first step, ppdo-b-peg-b-ppdo triblock copolymer was synthesized via a ring-opening polymerization of p-dioxanone (pdo) monomer with poly (ethylene glycol) (peg) using stannous octoate (sn(oct)2) as the cataly...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2016
masumeh gilanizadeh behzad zeynizadeh

this study represents a highly efficient and regioselective ring-opening of epoxides with acetic anhydride in the presence of naoac·3h2o at solvent-free conditions. the ring-opening of different classes of epoxides were carried in oil bath (70-80 °c) to afford 1,2-diacetates in high to excellent yields

In this protocol, 3-(2-carboxybenzoyl)-1-methyl-1H-imidazol-3-ium chloride [Cbmim]Cl and sulfonic acid functionalized pyridinium chloride [pyridine-SO3H]Cl as a new, reusable, and green Brønsted acidic ionic liquid (BAIL) catalyst were synthesized and successfully used for the one-pot ring opening of epoxide with sodium azide (NaN3) in water at room temperature. Epoxides under ring-opening easi...

Straightforward conversion of (+)-6,8-dimethoxy-3,4-dihydro-3- undecylisocoumarin (3) to the title isocoumarin was carried out. Hydrolytic ring opening of (3) afforded the hydroxy acid (4) which was immediately oxidized to keto acid (5) using chromic acid, Cyclodehydration of (5) afforded the 6,8- dimethoxy-3-undecylisocoumarin (6) which on selective demethylation of 8- methoxy group furni...

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