21032-12-2Relevant academic research and scientific papers
Improvement of a biomimetic porphyrin catalytic system by addition of acids.
Segrestaa, Jerome,Verite, Philippe,Estour, Francois,Menager, Sabine,Lafont, Olivier
, p. 744 - 748 (2007/10/03)
The conditions of the use of the manganese/porphyrin/imidazole system needed to be improved in order to obtain larger amounts of models of metabolites. An increase of the oxidation yields and a better preservation of this catalytic system have been obtained on the examples of various alkanes, by an acid addition in the reaction mixture. Three manganoporphyrins were checked for evaluation of the reaction. These results were extended to molecules of therapeutical interest such as ibuprofen and phenylbutazone.
Copper-catalyzed homolytic and heterolytic benzylic and allylic oxidation using tert-butyl hydroperoxide
Rothenberg, Gadi,Feldberg, Liron,Wiener, Harold,Sasson, Yoel
, p. 2429 - 2434 (2007/10/03)
Allylic and benzylic alcohols were oxidized in good yields to the respective ketones by tert-butyl hydroperoxide (TBHP) in the presence of copper salts under phase-transfer catalysis conditions. This dehydrogenation was found to proceed via a heterolytic mechanism. CuCl2, CuCl, and even copper powder were equally facile as catalysts, as they were all transformed in situ to Cu(OH)Cl which was extracted into the organic phase by the phase-transfer catalyst (PTC). Deuterium labeling experiments evidenced the scission of the benzylic C-H bond in the rate-determining step. Nonproductive TBHP decomposition was not observed in the presence of the alcohol substrates. Conversely, the oxygenation of π-activated methylene groups in the same medium was found to be a free radical process, and the major products were the appropriate tert-butyl peroxides. Catalyst deactivation, solvent effects, and extraction effects are discussed. By applying Minisci's postulations concerning the relative reactivity of TBHP molecules towards tert-butoxyl radicals in protic and nonprotic environments, the coexistence of the homolytic and the heterolytic pathways can be explained. A complete reaction mechanism is proposed, wherein the free-radical oxidation obeys Kochi's mechanism, and the heterolytic dehydrogenation is based on either a high-valent CuIV=O species or a [Cu(OH)Cl]2 species.
Copper catalyzed oxidation of tetralin to 1-(tert-butylperoxy)-tetralin by aqueous tert-butylhydroperoxide under phase transfer conditions
Feldberg, Liron,Sasson, Yoel
, p. 2063 - 2066 (2007/10/03)
Selective α-peroxidation of tetralin by TBHP is catalyzed by copper salts with the aid of quaternary ammonium compounds in an aqueous-organic biphasic system.
Preparation of Oxidation Catalysts by Immobilization and Isolation of Metal Complexes into Monolayer Matrix on Silica Surface
Miki, Keiji,Sato, Yoshiki
, p. 813 - 816 (2007/10/02)
Immobilization and isolation of cobalt-pyridine complexes in the fence of monolayer matrix on silica surface provided the active catalysts for oxidation of 1,2,3,4-tetrahydronaphthalene
