Easy and Selective Method for the Synthesis of Various Mono-O-functionalized Calix[4]arenes: De-O-functionalization Using TiCl4
摘要:
An efficient and selective method for the monofunctionalization of p-tert-butylcalix[4]arene is described A mono-de-O-functionalization of disubstituted p-tert-butylcalix[4]arenes using titanium tetrachloride was developed to synthesize a series of monosubstituted p-tert-butylcalix[4]arenes with the pendant functions being ethoxycarbonylmethyloxy, 3-ethoxycarbonylpropyloxy, cyanomethyloxy, 3-cyanopropyloxy, 4-bromobutyloxy, 3-hydroxypropyloxy, propyloxy, 2-methylpropyloxy, 3-butynyloxy, and 3-cyanopropyloxy groups The reaction mechanism of the formation of 5,11,17,23-tetra-tert-butyl-26,27,28-trihydroxy-25-(3-ethoxycarbonylpropyloxy) calix[4]arene was studied by H-1 NMR and GC/mass spectroscopy monitoring Reaction of TiCl4 with the disubstituted p-tert-butylcalix[4]arene produced the corresponding dioxocalix[4]arene titanium dichloride complex, which undergoes elimination of ethyl 4-chlorobutyrate, leading to a trioxocalix[4]arene titanium dichloride complex and to monosubstituted calix[4]arene after hydrolysis These two complexes were also synthesized, isolated, and fully characterized
Molecular drug-organiser: Synthesis, characterization and biological evaluation of penicillin V and/or nalidixic acid calixarene-based podands
摘要:
Two well-known antibiotic heterocycles, the 'quinolone' nalidixic acid and the beta-lactam penicillin V, active at different levels of the bacterial growth process, have been attached via an ether-ester junction to the p-tert-butylcalix[4] arene lower rim, in alternate position. The resulting hydrophobic molecular drug-organisers were fully characterized, and evaluated over two Gram negative and three Gram positive reference strains, using disk diffusion assays with disks impregnated with solution of title compound in pure DMSO. An interesting activity was observed over Staphylococcus aureus ATCC 25923 with the dissymmetrical podand incorporating one penicillin and one nalidixic ester moieties. (C) 2011 Elsevier Ltd. All rights reserved.
spectrometry and fluorescence as well as 1D and 2D NMR techniques. It was found that all three calixarenes form a complex with rhodamine dyes with a 1:1 composition. The association constants of calixarene-dye complexes with sulfonate calixarenes, especially in the case of tetra-anionic calixarene, turned out to be higher compared with carboxyl calixarene due to the more intense electrostatic interactions. For
Calix[4]arene-Linked Bisporphyrin Hosts for Fullerenes: Binding Strength, Solvation Effects, and Porphyrin−Fullerene Charge Transfer Bands
作者:Ali Hosseini、Steven Taylor、Gianluca Accorsi、Nicola Armaroli、Christopher A. Reed、Peter D. W. Boyd
DOI:10.1021/ja066031x
日期:2006.12.1
hosts for supramolecular binding of fullerene guests. Fullerene affinities were optimized by varying the nature of the covalent linkage of the porphyrins to the calixarenes. Binding constants for C60 and C70 in toluene were explored as a function of substituents at the periphery of the porphyrin, and 3,5-di-tert-butylphenyl groups gave rise to the highest fullerene affinities (26,000 M(-1) for C60). The
Two tetra-p-tert-butyl-calix[4]arene species bearing one or two anti-HSV aciclovir units tethered via carbodiester linkages at the lower rim were synthesized as possible antiviral prodrugs. The amphiphilic properties of these derivatives were studied using Langmuir balance at the airâwater and airâcarbonate buffer interfaces; the monolayers formed were stable on both subphases. Monolayers formed with these molecules on a carbonate buffer subphase at pH 10 and 37 °C were then used for monitoring hydrolysis of the diester linkage. The release of free aciclovir of around 30% in 3 days was observed with both derivatives, as shown with HPLC.
Cycloalkylations of p-tert-butylcalix[4]arene (CA) and p-tert-butylthiacalix[4]arene (TCA) with various aliphatic glycols were performed under the Mitsunobu protocol using the DEAD/TPP system. CA gave 1,3-dialkylated diols, while C-2-C-10 glycols gave 1,2- and 1,3-bridged calixarenes. The reaction of TCA with C-2 diols afforded sulfonium phenoxide betaines via O,S-cyclization, which is the first example for the alkylation of the sulfide bridge.
Molecular drug-organiser: Synthesis, characterization and biological evaluation of penicillin V and/or nalidixic acid calixarene-based podands
作者:Adel Ben Salem、Guillaume Sautrey、Stéphane Fontanay、Raphaël E. Duval、Jean-Bernard Regnouf-de-Vains
DOI:10.1016/j.bmc.2011.10.031
日期:2011.12
Two well-known antibiotic heterocycles, the 'quinolone' nalidixic acid and the beta-lactam penicillin V, active at different levels of the bacterial growth process, have been attached via an ether-ester junction to the p-tert-butylcalix[4] arene lower rim, in alternate position. The resulting hydrophobic molecular drug-organisers were fully characterized, and evaluated over two Gram negative and three Gram positive reference strains, using disk diffusion assays with disks impregnated with solution of title compound in pure DMSO. An interesting activity was observed over Staphylococcus aureus ATCC 25923 with the dissymmetrical podand incorporating one penicillin and one nalidixic ester moieties. (C) 2011 Elsevier Ltd. All rights reserved.