نتایج جستجو برای: benzil
تعداد نتایج: 269 فیلتر نتایج به سال:
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. ...
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...
[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...
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...
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...
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....
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...
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...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید