نتایج جستجو برای: benzil

تعداد نتایج: 269  

2008
Alan M. Schwartz

Gravitation is parity symmetric or antisymmetric. Mass distribution parity divergence varies from χ = 0 (achiral) to χ = 1 (perfect). A parity Eötvös experiment contrasts chemically and macroscopically identical enantiomorphic space groups P3121 and P3221 α-quartz single crystal test masses. A parity calorimetry experiment contrasts P3121 and P3221 benzil single crystals’ enthalpies of fusion. ...

Journal: :Acta Chemica Scandinavica 1987

Journal: :organic chemistry research 2016
seyyed jafar saghanezhad alireza kiasat

one-pot preparation of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles has been conducted in the presence of poly(4-vinylpyridinium butane sulfonic acid) hydrogen sulfate, p(4vpbsa)hso4, as an efficient dual acidic catalyst under solvent-free conditions. reusability of the catalyst, easy work-up procedure, eco-friendly reaction conditions, short reaction times and high yields of th...

Journal: :Organic letters 2003
Giulio G Muccioli Johan Wouters Jacques H Poupaert Bernadette Norberg Wolfgang Poppitz Gerhard K E Scriba Didier M Lambert

[reaction: see text] A new access to benzhydryl-phenylureas is described. These new interesting urea derivatives were obtained by reaction of substituted benzils with substituted phenylureas under microwave irradiation. Phenylthiourea, when reacted with benzil, gave 3-phenyl-thiohydantoin. Moreover, benzylurea, as phenethylurea, gave the corresponding 3-substituted hydantoin derivatives, demons...

Journal: :Chemical & pharmaceutical bulletin 2012
Yu-Hsuan Lan Yi-Ting Peng Tran-Dinh Thang Tsong-Long Hwang Do-Ngoc Dai Yann-Lii Leu Wan-Chun Lai Yang-Chang Wu

Further investigation of the methanolic extract of Fissistigma latifolium resulted in two new compounds whose structures were assigned as 2,5,6,7-tetramethoxyflavan (1) and 2'-hydroxy-4',5',6'-trimethoxybenzil (2). These two compounds were determined on the basis of chemical and spectroscopic evidences. Compound 2 is the first report of benzil from Fissistigma species. 2,5,6,7-Tetramethoxyflava...

2006
Mauro V. de Almeida Joana Darc S. Chaves Ana Paula Soares Fontes Eloi T. César Marcel Gielen

Este trabalho descreve a síntese e a caracterização de onze novos complexos de platina(II), contendo como ligantes derivados da 1,2-fenilenodiamina, da N-benzil etilenodiamina, e da 2ou 4-picolina. Os complexos foram preparados em rendimentos satisfatórios pela reação dos ligantes com K 2 [PtCl 4 ]. É descrita também a atividade citotóxica de um dos complexos de platina(II), em sete linhagens d...

Journal: :Organic & biomolecular chemistry 2014
Daniele Ragno Olga Bortolini Pier Paolo Giovannini Alessandro Massi Salvatore Pacifico Anna Zaghi

An operationally simple one-pot, two-step procedure for the desymmetrization of benzils is herein described. This consists in the chemoselective cross-benzoin reaction of symmetrical benzils with aromatic aldehydes catalyzed by the methyl sulfinyl (dimsyl) anion, followed by microwave-assisted oxidation of the resulting benzoylated benzoins with nitrate, avoiding the costly isolation procedure....

Journal: :Organic & biomolecular chemistry 2016
Martina L Contente Immacolata Serra Luca Palazzolo Chiara Parravicini Elisabetta Gianazza Ivano Eberini Andrea Pinto Benedetta Guidi Francesco Molinari Diego Romano

A recombinant ketoreductase from Pichia glucozyma (KRED1-Pglu) was used for the enantioselective reduction of various mono-substituted acetophenones. Reaction rates of meta- and para-derivatives were consistent with the electronic effects described by σ-Hammett coefficients; on the other hand, enantioselectivity was determined by an opposite orientation of the substrate in the binding pocket. R...

2008
Hoong-Kun Fun Reza Kia

In the mol-ecule of the title compound, C(16)H(14)O(2), a substituted benzil, the dicarbonyl unit has an s-trans conformation. This conformation is substanti-ated by the O-C-C-O torsion angle of 108.16 (15)°. The dihedral angle between the two aromatic rings is 72.00 (6)°. In the crystal structure, neighbouring mol-ecules are linked together by weak inter-molecular C-H⋯O hydrogen bonds and weak...

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