- Green and highly selective protocol for the synthesis of oximes
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A green and efficient protocol has been developed for the synthesis of either exclusively a monoxime or exclusively a dioxime from a host of 1,2-dicarbonyl compounds on silica.
- Ghosh, Pranab,Subba, Raju
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p. 529 - 532
(2013/11/06)
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- Screening of ligands for the Ullmann synthesis of electron-rich diaryl ethers
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In the search for new ligands for the Ullmann diaryl ether synthesis, permitting the coupling of electron-rich aryl bromides at relatively low temperatures, 56 structurally diverse multidentate ligands were screened in a model system that uses copper iodide in acetonitrile with potassium phosphate as the base. The ligands differed largely in their performance, but no privileged structural class could be identified.
- Otto, Nicola,Opatz, Till
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supporting information; experimental part
p. 1105 - 1111
(2012/09/07)
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- Oxidoperoxidotungsten(VI) complexes with secondary hydroxamic acids: Synthesis, structure and catalytic uses in highly efficient, selective and ecologically benign oxidation of olefins, alcohols, sulfides and amines with H2O2 as a terminal oxidant
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The reaction of a solution of freshly precipitated WO3 in H 2O2 separately with the secondary hydroxamic acids N-benzoyl-N-phenylhydroxamic acid (BPHAH), N-benzoyl-Northo-tolylhydroxamic acid (BOTHAH), N-benzoyl-N-meta-tolylhydroxamic acid (BMTHAH), N-benzoyl-N-para- tolyl-hydroxamic acid (BPTHAH) and N-cinnamyl-N-phenylhy-droxamic acid (CPHAH) afforded [WO(O2)(BPHA)2] (1), [WO(O2)(BOTHA) 2] (2), [WO(O2)(BMTHA)2] (3), [WO(O 2)-(BPTHA)2] (4) and [WO(O2)(CPHA)2] (5), respectively. Aqueous tungstate solution, on reaction with all these hydroxamic acids, produced [W(O)2(hydroxamato)2] (6). The complexes show excellent catalytic functions in the oxidation of (a) olefins at room temperature in the presence of NaHCO3 as promoter, (b) alcohols, sulfides and amines, at reflux, with H2O2 as a terminal oxidant, yielding a high turnover number (TON), the highest being for olefin-to-epoxide conversion. An attempt to synthesize peroxide-rich complexes of the type PPh4[WO(O2)2(hydroxamato)] (7), for example PPh4[WO-(O2)2BMTHA] (7C), resulted in the isolation of PPh4[WO-(O2)2(C 6H5COO)] (8), which was probably obtained by the hydrolysis of coordinated BMTHA. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Maiti, Swarup K.,Dinda, Subhajit,Banerjee, Surajit,Mukherjee, Alok K.,Bhattacharyya, Ramgopal
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experimental part
p. 2038 - 2051
(2009/03/11)
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- Oxoperoxo molybdenum(VI) and tungsten(VI) and oxodiperoxo molybdate(VI) and tungstate(VI) complexes with 8-quinolinol: Synthesis, structure and catalytic activity
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A solution obtained by dissolving MoO3 in a moderate excess of H2O2 reacts with 8-quinolinol (QOH) to give [MoO(O 2)(QO)2] (1), but, when the same reaction is conducted with a large excess of H2O2, an anionic complex is formed, which reacts with PPh4Cl to give the corresponding salt [MoO(O 2)2(QO)][PPh4] (2 · PPh4). Freshly prepared WO3 behaves the same way and, depending on the amount of H2O2 used, as above, produces either [WO(O 2)(QO)2] (3) or [WO(O2)2(QO)] [PPh4] (4 · PPh4), respectively. Crystallographic analyses reveal the coordination geometries around the metal center in these complexes to be distorted pentagonal bipyramids. These compounds show interesting catalytic properties in the oxidation of alcohols using H 2O2 as the terminal oxidant. In the case of aromatics, including benzylic and cinnamylic alcohols, the oxidation occurs selectively, affording aldehydes or ketones with reasonably high turnover numbers. Taking benzyl alcohol as a representative case, a probable mechanism of the alcohol-to-aldehyde conversion mediated by the prepared catalysts is suggested. The oxidation of aliphatic primary alcohols, under the same conditions, does not show the above selectivity: the reaction yields the corresponding aldehydes as well as carboxylic acids. The work was also extended to study the catalytic activity towards the oxidation of phenol and various sulfides and amines using the same oxidants. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2005.
- Maiti, Swarup K.,Banerjee, Surajit,Mukherjee, Alok K.,Abdul Malik,Bhattacharyya, Ramgopal
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p. 554 - 563
(2007/10/03)
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- Kit for the preparation of technetium TC 99m teboroxime myocardial perfusion agent
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A kit containing a solution of boronic acid adducts of technetium-99 m dioxime complexes; and hydroxypropyl gamma cyclodextrin to maintain the solution free of particulate matter originating from the formulation.
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- Uranyl Compounds with α-Dioximes: Mixed-Ligand Carbonatooxalate Complexes
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The interaction of uranyl complexes with α-dioximes having different structures in a carbonate-oxalate system was studied. It was shown that the pathway of the reaction and the compositions and the structures of the nascent complexes were significantly influenced by the α-dioxime structure. An X-ray diffraction study of (C2N2H10)2[(UO2) 2(CO3)(C2O4)2(C 3H4N2O2)] · H2O single crystals was carried out. The complex has a binuclear structure with bridging carbonate and methylglyoximate groups.
- Beirakhov,Orlova,Gorbunova,Mikhailov,Shchelokov
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p. 1414 - 1419
(2008/10/08)
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- PREPARATION AND SOME PROPERTIES OF 2H-IMIDAZOLE 1,3-DIOXIDES, DERIVATIVES OF ALICYCLIC 1,2-DIOXIMES
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The corresponding 2H-imidazole 1,3-dioxides were obtained by the reaction of cyclohexanedione and cycloheptanedione 1,2-dioximes with acetone, cyclopentanone, and methyl ethyl ketone.The reactions of these compounds with hydroxylamine hydrochloride, NaBH4, a Grignard reagent, and acetic anhydride in the presence of H2SO4 were studied in the case of 2,2-dimethyl-4,5,6,7-tetrahydro-2H-benzimidazole 1,3-dioxide.Bromination of the latter and 2,2-dimethylcyclohepta-2H-imidazole 1,3-dioxide with N-bromosuccinimide gave the corresponding dibromo derivatives, the bromineatoms in which are replaced by acetoxy and hydroxy groups. 4,7-Dihydroxy-2,2-dimethyl-4,5,6,7-tetrahydro-2H-benzimidazole 1,3-dioxide, which was obtained by oxidation with MnO2, was converted to a quinone, viz., 2,2-dimethyl-4,7-dioxo-4,7-dihydro-2H-benzimidazole 1,3-dioxide.
- Samsonov, V. A.,Volodarskii, L. B.
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p. 628 - 633
(2007/10/02)
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