نتایج جستجو برای: tetrahydropyranyl ethers

تعداد نتایج: 7237  

2012
L. S. Levitt B. W. Levitt

Chemistry Department, College of Science, University of Texas, El Paso, T X 79968, USA Z. Naturforsch. 84b, 614-620 (1979); received September 11, 1978 Relative Basicity Parameter, Conductivity of Protonated Ethers, Calculation of PKA'S for R20H+ It is shown in this paper that a consistent set of values of pKBH+ for 24 ethers, in good agreement with the few which have been obtained b y other me...

Journal: :Physical chemistry chemical physics : PCCP 2008
Bogdan C Ibănescu Michael Allan

A difference was observed in the reactivity of alcohols and ethers toward free electrons. Whereas the lowest core-excited state of the negative ion-a 2(n,3s2) Feshbach resonance-of the alcohols readily dissociates by losing a hydrogen atom, ethers show no observable signal from this resonance. This difference in reactivity has a parallel in the anomalous shapes and energies of the parent states...

Journal: :Topics in current chemistry 2012
Martin Kaller Sabine Laschat

In this chapter, a comprehensive review over the entire reserarch on liquid crystalline crown ethers since their discovery will be given. Monomeric and polymeric molecules containing crown ethers as well as aza crown ethers, thia crown ethers and crown ethers with several different heteroatoms will be presented. Liquid crystallinity is, in most cases, caused by the substituents attached to the ...

2017
Seyed Hossein Jamali Mahinder Ramdin Tim M Becker Shwet Kumar Rinwa Wim Buijs Thijs J H Vlugt

Crown-ethers have recently been used to assemble porous liquids (PLs), which are liquids with permanent porosity formed by mixing bulky solvent molecules (e.g., 15-crown-5 ether) with solvent-inaccessible organic cages. PLs and crown-ethers belong to a novel class of materials, which can potentially be used for gas separation and storage, but their performance for this purpose needs to be asses...

Bita Mohtat Delaram Abdolahi,

7-hydroxy coumarin undergoes neutral conditions with alkyl propiolates in the presence of triphenylphosphine, and bysubstituation the corresponding aryl vinyl ethers was obtained in good yields

2017
Ryan DeAngelis Amy Solinski David A. Hunt

In a heretofore-unreported reaction, 1,2-cyclohexandione reacts with a variety of alcohols under mild acid-catalyzed dehydration conditions to afford not only ethers of 1,2cyclohexanedione but the corresponding aryl ethers as well in moderate to good yield.

Journal: :The Journal of organic chemistry 2004
Michael E Jung Andreas Maderna

We describe the first synthesis of homoallyl ethers from acetals and allyltrimethylsilane using microwave heating and CuBr as a promoter. This method works best for aromatic acetals, giving the corresponding homoallyl ethers in good to quantitative yield.

2014
Cheng-Chung Lee Manuel Maestre-Reyna Kai-Cheng Hsu Hao-Ching Wang Chia-I Liu Wen-Yih Jeng Li-Ling Lin Richard Wood Chia-Cheng Chou Jinn-Moon Yang Andrew H-J Wang

Crown ethers are small, cyclic polyethers that have found wide-spread use in phase-transfer catalysis and, to a certain degree, in protein chemistry. Crown ethers readily bind metallic and organic cations, including positively charged amino acid side chains. We elucidated the crystal structures of several protein-crown ether co-crystals grown in the presence of 18-crown-6. We then employed biop...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2008
Kensuke Kurahashi Shigeo Umetani Yoshiki Sohrin

Novel 4-acyl-5-pyrazolones having aza-15-crown-5 (HPMP-A15C5) and aza-18-crown-6 (HPMP-A18C6) moieties as an intramolecular synergist have been synthesized by simple coupling reactions between 1-phenyl-3-methyl-4-chloroacetyl-5-pyrazolone and the corresponding azacrown ethers. The solvent extraction of the divalent metal ions (Mn(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+) and Pb(2+)) were exam...

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