نتایج جستجو برای: crown ethers

تعداد نتایج: 25024  

2017
Carsten von Hänisch

Compounds consisting of [M(1,2-disila-[3n]crown-n)] (M = Mg, Ca, Sr, Ba; n = 5, 6) and [Ba(1,2-disilabenzo[18]crown-6)] cations and different anions were obtained by equimolar reaction of the hybrid disila-crown ethers 1,2-disila[15]crown-5 (1), 1,2-disila[18]crown-6 (2) and 1,2-disila-benzo[18]crown-6 (7) with alkaline earth metal salts. Even with strongly coordinating anions such as Br or I s...

2017
Carsten von Hänisch

Compounds consisting of [M(1,2-disila-[3n]crown-n)] (M = Mg, Ca, Sr, Ba; n = 5, 6) and [Ba(1,2-disilabenzo[18]crown-6)] cations and different anions were obtained by equimolar reaction of the hybrid disila-crown ethers 1,2-disila[15]crown-5 (1), 1,2-disila[18]crown-6 (2) and 1,2-disila-benzo[18]crown-6 (7) with alkaline earth metal salts. Even with strongly coordinating anions such as Br or I s...

Journal: :ChemistrySelect 2021

Abstract Novel organomagnesium crown ether molecules have been computationally characterized using density functional theory (DFT). Monomer units of MgC 6 are used as building blocks. Isomers H 2 extensively explored both DFT and coupled‐cluster methods in the past by some us. It had concluded that seven‐membered ring isomer, 1‐magnesacyclohept‐4‐en‐2,6‐diyne, was thermodynamically most stable ...

Journal: :Chemistry 2021

Carbohydrate-based crown ethers represent a special group of chiral phase transfer catalysts. Several derivatives these macrocycles have been synthesized in our research group. Among compounds, monoaza-15-crown-5 lariat proved to be effective and enantioselective catalysts certain reactions. Those azacrown incorporating various carbohydrate moieties the macrocyclic structure are reviewed, which...

Journal: :journal of membrane science and research 0
n.s. rathore prefre, barc complex, nuclear recycle board, barc, tarapur, distt. palghar, 401502, maharashtra, india ana maria sastre department of chemical engineering, universitat politècnica de catalunya etseib diagonal 647, 08028 barcelona, spain anil kumar pabby prefre, barc complex, nuclear recycle board, barc, tarapur, distt. palghar, 401502, maharashtra, india

membrane assisted liquid extraction(male) technologies are gaining an important role as an extraction /separation technique for actinides and are being deployed as a  promising tool for remediation of nuclear waste generated in the reprocessing plant and other radioactive wastes containing a trace level of radionuclides. the present contribution outlines the classification of membrane assisted ...

Journal: :Organic & biomolecular chemistry 2014
Hiroshi Matsubara Takahiko Maegawa Yasuaki Kita Takato Yokoji Akihiro Nomoto

1,4-Benzoquinone derivatives bearing trifluoromethyl, perfluorobutyl and perfluorohexyl groups were prepared and employed in the deprotection of silyl ethers. The fluorous character of these compounds was examined by measuring the partition coefficient between the fluorous and organic solvents. The benzoquinone derivatives showed significant fluorous character, indicating that they can be recov...

Journal: :Organic & biomolecular chemistry 2008
Vahuni Karapetyan Satenik Mkrtchyan Andreas Schmidt Jörg-Peter Gütlein Alexander Villinger Helmut Reinke Haijun Jiao Christine Fischer Peter Langer

A variety of functionalized 3,4-benzo-7-hydroxy-2,9-diazabicyclo[3.3.1]non-7-enes were prepared by one-pot cyclizations of 1,3-bis(silyl enol ethers) with quinazolines. The mechanism of the cyclization was studied by B3LYP/6-31G(d) density functional theory computations. The products could be functionalized by Suzuki cross-coupling reactions. The reaction of 1,3-bis(silyl enol ethers) with phth...

Journal: :Organic & biomolecular chemistry 2011
Jie-Ping Wan Chunping Wang Yunyun Liu

The O-arylation of o-enaminone functionalized phenols, namely, (E)-3-(dimethylamino)-1-(2-hydroxyphenyl)prop-2-en-1-ones, has been achieved via a self-promoted process in the presence of CuI, which provided a class of new biaryl ethers bearing a reactive enaminone fragment. The reactions were performed under mild conditions and the functionalized biaryl ether products have been found as useful ...

Journal: :Chemical communications 2013
Itaru Suzuki Makoto Yasuda Akio Baba

The coupling of acetals with various alkynes was achieved using only 1 mol% of inexpensive and mild Lewis acid ZnCl2, which furnished propargyl ethers. The coupling was catalyzed by Zn(OMe)Cl, which was generated in situ to form an alkynylzinc species. This protocol was allowed to expand to a one-pot subsequent reaction with allylchlorosilane to obtain a 1,4-enyne product.

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