نتایج جستجو برای: epoxy compounds

تعداد نتایج: 239236  

Journal: :Chemical communications 2003
Hongda Zhao Brian L Pagenkopf

The stereospecific and regioselective C(3) alkynylation of trisubstituted epoxides has been achieved with lithium alkynyl trimethylaluminium ate complexes in the presence of BF3 x OEt2.

Journal: :Chemical communications 2008
Kouki Ogawa Yasuhito Koyama Isao Ohashi Itaru Sato Masahiro Hirama

Formation of an epoxide before 9-membered ring cyclization and SmI2 mediated reductive olefination in the presence of the epoxide successfully produced the epoxybicyclo[7.3.0]dodecadienediyne core of the kedarcidin chromophore.

Journal: :Chemical communications 2010
Kazuhiro Watanabe Junji Sakurai Hideki Abe Tadashi Katoh

The first enantioselective total synthesis of (+)-stachyflin, a potential anti-influenza A virus agent, was achieved; the method features a BF(3).Et(2)O-induced domino epoxide-opening/rearrangement/cyclization reaction to stereoselectively form the requisite pentacyclic ring system in one step.

2015
Geoffrey M T Smith Paul M Burton Christopher D Bray

The development of the homologous Julia-Kocienski reaction has led to the discovery of two new reaction modes of epoxides with sulfones. These pathways allow rapid and direct access to a range of γ-sultones and γ-sultines.

Journal: :Journal of the American Chemical Society 2004
Zhangjie Shi Chuan He

A gold-catalyzed cyclialkylation of electron-rich arenes with tethered epoxides afforded 3-chromanols stereospecifically.

Journal: :The Journal of antibiotics 2003
Kazunobu Yamamoto Hiroko Hatano Masayoshi Arai Kazuro Shiomi Hiroshi Tomoda Satoshi Omura

Structures of three novel compounds designated monordens C to E, isolated from the fermentation broth of amidepsine-producing fungus Humicola sp. FO-2942, were elucidated by spectroscopic evidence. Monordens C is 6,7-dihydromonorden A. Monordens D and E lack the epoxide moiety of monordens C and B, respectively.

2016
M. Fache B. Boutevin S. Caillol

Epoxy thermosets were prepared from mixtures of phenolics modelling the product stream of the ligninto-vanillin process. Vanillin is one of the only mono-aromatic compounds produced on an industrial scale from lignin. This process leads to mixtures of phenolic compounds. Isolation of pure vanillin is costly both economically and environmentally. The present work demonstrates that these purifica...

Journal: :Molecules 2015
Xiao-Wei Hong Yu-Qiang Zhou Cui-Bing Bai Nai-Xing Wang Yalan Xing Wei Zhang Yan-Jing Wang Xing-Wang Lan Yu Xie Yi-He Li

An efficient multi-component reaction to synthesize multi-substituted 1,3-oxazolidine compounds of high optical purity was described. All the products were well-characterized and the absolute configuration of one chiral center was determined. The plausible mechanism was proposed and a kinetic resolution of epoxides process was confirmed.

2009
L. C.R. Andrade J. A. Paixão M.J.M. de Almeida F. M. Fernandes Roleira E. J. Tavares da Silva

The title compound, C(21)H(32)O(3), results from modifications of the A and D rings of the aromatase substrate androstenedione. Ring A adopts a conformation between 10β-sofa and 1α,10β half-chair. Rings B and C are in slightly flattened chair conformations. Ring D approaches a 13β-envelope conformation, probably due to the acet-oxy substituent, and shows a very short Csp(3)-Csp(3) bond next to ...

2002
Tomoyuki HANAOKA Qing LI Junko IMAGAWA Masahito TAGUCHI Masayasu MINAMI Shoichiro TSUGANE

Epoxy resins have been widely used in commercial applications, and their adverse health effects have been mostly reported in occupational settings. The most frequent adverse effects are irritation or allergic mechanisms involving the dermal and respiratory systems. Sensitization is usually caused by low molecular weight or short-chain compounds. We report here two workers exposed to an epoxy re...

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