123-11-5Relevant articles and documents
CuII-salan compounds: Synthesis, characterization and evaluation of their potential as oxidation catalysts
Ad?o, Pedro,Barroso, Sónia,Avecilla, Fernando,Oliveira, M. Concei??o,Pessoa, Jo?o Costa
, p. 212 - 223 (2014)
We report the synthesis and characterization of several salan-type Cu II complexes. Suitable crystals suitable for X-ray diffraction were obtained for several of the CuII complexes, including a half-salen compound, revealing square-planar coordination environments common to d9 species. The CuII-salan complexes are tested as catalysts in sulfoxidation, alkene oxidation, and oxidative naphthol coupling. At room temperature the compounds exhibit low to moderate catalytic activity in sulfoxidations and alkene oxidations, but no activity in oxidative naphthol coupling. The saturated coordination environments around the Cu centers probably are the main reason for the lower catalytic activities compared to the Ti- and V-salan analogs. Spectroscopic and mass spectrometry studies revealed that the CuII-salan complexes decompose, in the presence of H2O2, significantly faster at 40 °C than at room temperature. The catalytic activity observed is probably due to the CuII-salan degradation products, observed in the mass spectrometry studies, and not to the original CuII-salan precursors.
Syntheses of U3O8 nanoparticles form four different uranyl complexes: Their catalytic performance for various alcohol oxidations
Majumder, Ishani,Chatterjee, Sourav,Fischer, Roland C.,Neogi, Swarup Kumar,Mautner, Franz A.,Chattopadhyay, Tanmay
, p. 112 - 122 (2017)
Two dinuclear complexes namely [(UO2)2(L1)2(DMSO)2] (1) and [(UO2)2(L2)2(DMSO)2] (2) of two Schiff base ligands 2-[(2-hydroxy-3-methoxy-benzylidene)-amino]-2-hydroxymethyl propane-1,3-diol (HL1) and 2-[(3,5-dichloro-2-hydroxy-benzylidene)-amino]-2-hydroxymethyl-propane-1,3-diol (HL2) obtained by condensation of the aldehydes 2-hydroxy-3-methoxy-benzaldehyde and 3, 5-dichloro salicylaldehyde with tris(hydroxymethyl)aminomethane ammine, have been synthesized. On the other hand, when the two aldehydes were treated with uranyl nitrate two mononuclear complexes, [(UO2)(L3)2(DMSO)2] (3) and [(UO2)(L4)2(DMSO)2] (4), are obtained. The complexes are then heated at 800?°C in open atmosphere to obtain the U3O8 nanomaterials as the final product. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were employed to characterize the so obtained the U3O8 nanoparticles. Studies shows the synthesized U3O8 nanoparticles obtained from different complexes were different as far as morphology and size are concerned. All four different U3O8 nanoparticles explored as oxidising catalyst to oxidize alcohols where morphology of the nanoparticles controls the catalytic efficiency.
One-pot synthesis of silica gel confined functional ionic liquids: Effective catalysts for deoximation under mild conditions
Li, Dongmei,Shi, Feng,Guo, Shu,Deng, Youquan
, p. 265 - 268 (2004)
Several acid-functional ionic liquids were physically confined into the silica gel through a sol-gel process and used as effective catalysts for deoximation reactions, which proceeded under ambient temperatures without addition of any co-catalysts or oxidizing and reducing agents.
Synthesis and biological activity of hydroxylated analogs of RCAI-80
Shiozaki, Masao,Tashiro, Takuya,Koshino, Hiroyuki,Shigeura, Tomokuni,Watarai, Hiroshi,Taniguchi, Masaru,Mori, Kenji
, p. 9710 - 9725 (2013)
RCAI-80 is one of the ester analogs of KRN7000 (α-galactosylceramide) . This compound released mainly T helper 2 (Th2) cytokines, such as IL-4 rather than T helper 1 (Th1) cytokines, such as IFNγ from the invariant natural killer T (iNKT) cells. In addition, it has been known that some of the hydroxylated derivatives of KRN7000 make the cytokine secretion bias to Th2 by decreasing the IFNγ production to almost zero. This time, the three compounds having these two characteristic properties, namely an ester group and also some extra hydroxy groups existing on the ester side chain and/or on the 2-acyloxy-3,4-dihydroxyoctadecyl main chain of RCAI-80, were synthesized to examine the biological activities. As a result, it was found that these compounds made the cytokine secretion skew to Th2. Therefore, their effectiveness for experimental autoimmune encephalomyelitis (EAE) was examined. It was recognized that one of them showed moderate suppression of EAE symptom.
Nanostructured rutile TiO2 for selective photocatalytic oxidation of aromatic alcohols to aldehydes in water
Yurdakal, Sedat,Palmisano, Giovanni,Loddo, Vittorio,Augugliaro, Vincenzo,Palmisano, Leonardo
, p. 1568 - 1569 (2008)
Selective photocatalytic oxidation of aromatic alcohols to aldehydes was performed in water in the presence of TiO2 rutile photocatalysts that exhibited a low degree of crystallinity. The nanostructured rutile samples, prepared ex TiCl4 at very low temperature, ensured a selectivity toward the aldehyde 3 to 4-fold higher than the commercial rutile tested (Sigma-Aldrich). Copyright
Synthesis, characterization and catalytic activity of new Cr(III) complex in oxidation of primary alcohols to aldehydes
Noshiranzadeh, Nader,Bikas, Rahman,?lepokura, Katarzyna,Mayeli, Mina,Lis, Tadeusz
, p. 176 - 182 (2014)
New mononuclear complex of chromium(III), [Cr(bp)(N3)(CH 3OH)]·2CH3OH has been synthesized where H 2bp is N,N-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-N',N'- dimethylethylene-1,2-diamine. The complex was character
Gold nanoparticle-modified TiO2/SBA-15 nanocomposites as active plasmonic photocatalysts for the selective oxidation of aromatic alcohols
Chen, Yu,Li, Weizun,Wang, Jingyu,Yang, Qian,Hou, Qidong,Ju, Meiting
, p. 70352 - 70363 (2016)
The catalytic performance of noble-metal on mesoporous silica hosts has been widely investigated because the effects of surface plasmon resonance can open new avenues for the improvement of catalytic performance under light irradiation. In this study, a s
A ceric ammonium nitrate based oxidative cleavage pathway for the asymmetric aldol adducts of oxadiazinones derived from (1R,2S)-N-p-methoxybenzylnorephedrine
Leise, Austin R.,Comas, Nicole,Harrison, Doug,Patel, Dipak,Whitemiller, Eileen G.,Wilson, Jennifer,Timms, Jacob,Golightly, Ian,Hamaker, Christopher G.,Hitchcock, Shawn R.
, p. 1154 - 1162 (2017)
An N4-p-methoxybenzyloxadiazinone has been prepared from (1R,2S)-norephedrine through a process of reductive amination, N-nitrosation, reduction, and cyclization. The oxadiazinone was acylated and employed in the asymmetric aldol addition reaction with aromatic and aliphatic aldehydes to yield aldol adducts in isolated yields ranging from 54% to 90%. Selected aldol adducts were treated with ceric ammonium nitrate in aqueous acetonitrile to afford the desired β-hydroxycarboxylic acids through a tandem process of oxidative cleavage of the N4-p-methoxybenzyl group and acidic hydrolysis of the N3-acyl side chain. The β-hydroxycarboxylic acids were recovered in high diastereomeric purity as determined by 500 MHz 1H NMR spectroscopy and the absolute configuration was confirmed by polarimetry. The chiral auxiliary unit, the 3,4,5,6-tetrahydro-2H-1,3,4-oxadiazin-2-one (oxadiazinone), was converted into its corresponding 3,6-dihydro-2H-1,3,4-oxadiazin-2-one (oxadiazinone) through an oxidative pathway promoted by the ceric ammonium nitrate.
Lewis acid-catalyzed reactions of ethyl diazoacetate with aldehydes. Synthesis of α-formyl esters by a sequence of aldol reaction and 1,2- nucleophilic rearrangement
Kanemasa, Shuji,Kanai, Toshio,Araki, Takahiro,Wada, Eiji
, p. 5055 - 5058 (1999)
Ethyl diazoacetate reacts with a variety of aldehydes in the presence of a Lewis acid catalyst to give either β-keto esters or α-formyl esters, the types of products mainly depending upon the nature of Lewis acid catalysts employed. Reactions catalyzed by Lewis acids such as SnCl2 and SnCl4 provide β-keto esters via nucleophilic 1,2-hydride migration, while those catalyzed by trimethylsilyl triflate give α-formyl esters via migration of the substituent of the aldehyde. Reaction mechanisms are discussed.
New oligostilbenes having a benzofuran from Vitis vinifera 'Kyohou'
Ito, Junko,Takaya, Yoshiaki,Oshima, Yoshiteru,Niwa, Masatake
, p. 2529 - 2544 (1999)
Three new oligostilbenes having a benzofuran moiety, viniferifuran, (+)- vitisifuran A and (-)-vitisifuran B, were isolated from Vitis vinifera 'Kyohou'. The structures of these oligostilbenes including the absolute configuration were elucidated by spectroscopic and chemical methods. Furthermore, these were chemically transformed from (+)-ε-viniferin, (+)- vitisin A and (-)-vitisin B, respectively, whose absolute configurations are known.
