  Electrochemical study of two tris-O-substituted calix[4]arenes: 25,27-dipropoxy-26-hydroxy-28-benzoyloxycalix[4]arene(partial cone) and 25,27-dibenzyl-26-hydroxy-28-benzoyloxy-calix[4]-arene (partial cone). Electro synthesis of the corresponding calix[4]arene-monoquinones; ; Gabelica, Valérie  et alin Electrochemistry Communications (2006), 8(5), 761-766 The anodic oxidation of 25,27-dipropoxy-26-hydroxy-28-benzoyloxycalix[4]arene 1 and 25,27-dibenzyl-26-hydroxy-28-benzoyloxycalix[4]arene 2 in dichloromethane was investigated by electrochemical and ... [more ▼] The anodic oxidation of 25,27-dipropoxy-26-hydroxy-28-benzoyloxycalix[4]arene 1 and 25,27-dibenzyl-26-hydroxy-28-benzoyloxycalix[4]arene 2 in dichloromethane was investigated by electrochemical and spectroclectrochemical techniques. For both, the overall reaction is a two-electron oxidation of the phenolic group according to an ECE mechanism resulting in the ultimate formation of an observable phenoxylium cation. After reaction of the latter with traces of water and subsequent internal electron transfer, the corresponding calix[4]-monoquinones are formed. (c) 2006 Elsevier B.V. All rights reserved. [less ▲] Detailed reference viewed: 84 (5 ULg)Formation of upper rim acylated calix[4]arenes using a sacrifici al zinc anode; ; Gabelica, Valérie et alin Tetrahedron Letters (2005), 46(44), 7499-7502 A straightforward electrosynthetic method is described, which allows upper rim acylation of non-p-halogenated calix[4]-arenes. For example, a solution of tetrapropoxycalix[4]arene 4 was electrolysed in ... [more ▼] A straightforward electrosynthetic method is described, which allows upper rim acylation of non-p-halogenated calix[4]-arenes. For example, a solution of tetrapropoxycalix[4]arene 4 was electrolysed in the presence of ZnBr2, in an undivided cell fitted with a sacrificial zinc anode using pure acetonitrile as solvent, yielding an organozinc species, which was then treated with acetyl chloride in the presence of a palladium catalyst to afford 5,11-diacety1-25,26,27,28-tetrapropoxycalix[4]arene 5 in ca. 35% yield after workup. (c) 2005 Elsevier Ltd. All rights reserved. [less ▲] Detailed reference viewed: 74 (4 ULg)First synthesis of a '1,2-diquinone-calix[4]arene'. Interaction of its reduced form with Ag+; ; et al in Journal of Electroanalytical Chemistry (2002), 519(1-2), 123129 Electrochemical oxidation of 5,11,17,23-tetra-tert-butyl-25,26-bis(diphenylphosphinoylmethoxy)-27,28-dihydroxycalix[4]arene (3), a calixarene with two phosphoryl units appended on proximal positions ... [more ▼] Electrochemical oxidation of 5,11,17,23-tetra-tert-butyl-25,26-bis(diphenylphosphinoylmethoxy)-27,28-dihydroxycalix[4]arene (3), a calixarene with two phosphoryl units appended on proximal positions, affords the corresponding '1,2-diquinonecalix[4]arene' (4). The formation of 4 results from nucleophilic attack of residual water on anodically generated diphenoxylium. cations. Preliminary voltammetric experiments in CH3CN on a platinum electrode showed that 4 is suitable for electrochemical detection of the silver metal cation. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲] Detailed reference viewed: 83 (6 ULg) |
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