نتایج جستجو برای: williamson ether synthesis

تعداد نتایج: 430501  

Ehsan Fathollahi Hossein Mighani Mousa Ghaemy

In this paper, an efficient method for synthesis of aromatic polyesters containing schiff base units is described by preparation of two polyesters. These polyesters have been prepared by the reaction of terephthaloyl dichloride on Schiff bases derived from p-hydroxybenzyldehyde and 4,4-diamino diphenyl ether, 4,4-diamino diphenyl methane. The Polymers were characterized by IR, CHNS, thermal...

2013
An Mao El Barbary Hassan Moon G. Kim

A previous study of synthesizing low mole ratio urea–formaldehyde (UF) and urea–melamine–formaldehyde (UMF) resins, which included an acidic reaction step at the beginning of the typical resin synthesis procedure to obtain higher uron-type methylene–ether group contents, was repeated with the acidic reaction step extended to a higher viscosity. Compared to previous resins, the synthesized resin...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2013
Daniel I Benjamin Alyssa Cozzo Xiaodan Ji Lindsay S Roberts Sharon M Louie Melinda M Mulvihill Kunxin Luo Daniel K Nomura

Aberrant lipid metabolism is an established hallmark of cancer cells. In particular, ether lipid levels have been shown to be elevated in tumors, but their specific function in cancer remains elusive. We show here that the metabolic enzyme alkylglyceronephosphate synthase (AGPS), a critical step in the synthesis of ether lipids, is up-regulated across multiple types of aggressive human cancer c...

Journal: :Organic & biomolecular chemistry 2015
Xiaoxi Lin Zhiqiang Weng

A facile, efficient, single-step protocol for the synthesis of difluoromethyl enol ether derivatives by O-difluoromethylation of 1,3-diones via in situ generation of difluorocarbene from ClCF2CO2Et has been developed. The functional group tolerance, scalability of the reaction, and mild reaction conditions make it an attractive protocol for the synthesis of biologically relevant difluoromethyl ...

Journal: :Molecules 2004
Waldo H Correa Janet L Scott

A benign and efficient synthesis of chiral macrocyclic 'aza-crown' ethers of varying ring size is reported. The synthesis involves a Schiff base condensation of ether linked dialdehydes of varying chain length and (1R,2R)-(-)-1,2-diaminocyclohexane under mild conditions to yield the macrocycles, which are subsequently reduced to yield the diamino analogues.

Journal: :Chemical communications 2010
Qiao-Qiao Min Chun-Yang He Haibing Zhou Xingang Zhang

An efficient method for highly diastereoselective synthesis of quaternary α-trifluoromethyl α-amino acids was developed via indium mediated allylation of (R)-phenylglycinol methyl ether based imines of trifluoropyruvate in good yields with high diastereoselectivities at room temperature; to illustrate the application of this method in organic synthesis, 2-allyl-2-(trifluoromethyl) aziridine was...

Journal: :Organic letters 2003
Utpal Majumder Jason M Cox Jon D Rainier

[structure: see text] This manuscript describes our synthesis of the F-H subunit of gambierol. In addition to the synthesis of the tricycle, of note is an interesting protecting group influence on the generation of a C(23) C-glycoside as well as the use of ring-closing metathesis to generate a tetrasubstituted enol ether.

2011
Gordon J. Florence Joanne C. Morris Ross G. Murray Jonathan D. Osler Vanga R. Reddy Terry K. Smith

A stereocontrolled total synthesis of (+)-chamuvarinin, isolated from the root extract of Uvaria Chamae, utilizes a convergent modular strategy to construct the adjacently linked C15-C28 ether array, followed by a late-stage Julia-Kocienski olefination to append the butenolide motif. This constitutes the first total synthesis of (+)-chamuvarinin, defining the relative and absolute configuration...

2007
M. Grzesik A. Ptaszek J. Skrzypek P. Ptaszek

This work includes a modelling and simulation of dimethyl ether direct synthesis in a tubular type reactor with hybrid catalysts bed. The results of simulation show that the loading ratio of methanol synthesis and dehydration catalysts has a important influence on product yield.

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