نتایج جستجو برای: ring opening of epoxides

تعداد نتایج: 21178628  

2016
G. Trott P. K. Saini C. K. Williams

This article summarizes and reviews recent progress in the development of catalysts for the ring-opening copolymerization of carbon dioxide and epoxides. The copolymerization is an interesting method to add value to carbon dioxide, including from waste sources, and to reduce pollution associated with commodity polymer manufacture. The selection of the catalyst is of critical importance to contr...

Journal: :Applied Materials Today 2021

The covalent double functionalization of graphene oxide (GO) is an effective approach to tune the properties graphene-like materials. first step ring-opening reaction epoxides by amines, followed second consisting on nucleophilic addition GO hydroxyl groups ?,?-unsaturated carbonyl compound. benefit doubly functionalized possess different functions, confirmed measuring proton conductivity and s...

Journal: :Molecules 2012
Parviz Torabi Javad Azizian Shahab Zomorodbakhsh

We found that elemental iodine and bromine are converted to trihalide nucleophiles (triiodine and tribromide anion, respectively) in the presence of catalytic amounts of meso-tetraphenylporphyrins (H2TPP). Therefore a highly regioselective method for the synthesis of beta-haloalcohols through direct ring opening of epoxides with elemental iodine and bromine in the presence of H2TPPs as new cata...

Journal: :Molecules 2012
Celia Xochitl Hernández-Reyes Deyanira Angeles-Beltrán Leticia Lomas-Romero Eduardo González-Zamora Rubén Gaviño Jorge Cárdenas José Antonio Morales-Serna Guillermo E Negrón-Silva

New azanucleosides were obtained using sulphated zirconia (ZS) as catalyst in the nucleophilic oxirane ring opening reaction of 1-allyl-3-(oxiran-2-ylmethyl) pyrimidine-2,4(1H,3H)-dione and 1-allyl-5-methyl-3-(oxiran-2-ylmethyl)-pyrimidine-2,4(1H,3H)-dione, with (S)-prolinol. The new templates were obtained with good yields following a route which exploits the reactivity of epoxides in the pres...

Journal: :Molecules 2015
Markus Heiny V Prasad Shastri

Degradable aliphatic polyesters such as poly(lactic acid) are widely used in biomedical applications, however, they lack functional moieties along the polymer backbone that are amenable for functionalization reactions or could be the basis for interactions with biological systems. Here we present a straightforward route for the synthesis of functional α-ω epoxyesters as comonomers for lactide p...

Journal: :Journal of the American Chemical Society 2014
M Hassan Beyzavi Rachel C Klet Samat Tussupbayev Joshua Borycz Nicolaas A Vermeulen Christopher J Cramer J Fraser Stoddart Joseph T Hupp Omar K Farha

Porous heterogeneous catalysts play a pivotal role in the chemical industry. Herein a new Hf-based metal-organic framework (Hf-NU-1000) incorporating Hf6 clusters is reported. It demonstrates high catalytic efficiency for the activation of epoxides, facilitating the quantitative chemical fixation of CO2 into five-membered cyclic carbonates under ambient conditions, rendering this material an ex...

2008
Claudio J. Salomon

The regioselective opening of epoxides with organotin oxides 1 and 2, in presence of halogenated alcohols was developed, yielding the halohydrin derivatives. Introduction Epoxides are among the most versatile intermediates in organic chemistry due to the particular polarity and strength of their three member ring. Those characteristics make them in a very suitable substrate to the attack or man...

Journal: :Molecules 2008
Luis R Domingo Salvador Gil Margarita Parra José Segura

Addition of carboxylic acid dianions appears to be a potential alternative to the use of aluminium enolates for nucleophilic ring opening of epoxides. These conditions require the use of a sub-stoichiometric amount of amine (10% mol) for dianion generation and the previous activation of the epoxide with LiCl. Yields are good, with high regioselectivity, but the use of styrene oxide led, unexpec...

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