- Supramolecular Vesicles Coassembled from Disulfide-Linked Benzimidazolium Amphiphiles and Carboxylate-Substituted Pillar[6]arenes that Are Responsive to Five Stimuli
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Novel supramolecular vesicles based on host–guest systems were coassembled from carboxylate-substituted pillar[6]arene (CPA[6]) and disulfide-linked benzimidazolium amphiphiles, and the microstructures of the CPA-based supramolecular vesicles were clearly elaborated. The supramolecular vesicles showed controlled drug release in response to five stimuli, with glutathione, pH, CO2, Zn2+ions, and hexanediamine, leading to cleavage of the disulfide bonds, protonation of the carboxylate groups, metal chelation, and competitive binding. This is the first case of a smart pillararene-based supramolecular vesicle being integrated with five stimuli-responsive functions to meet the diverse requirements of controlled drug release. Importantly, each of the five stimuli is closely related to microenvironments of tumors and diseases of the human body. The smart stimuli-responsive supramolecular vesicles have promising applications in drug therapy of tumors and relevant diseases.
- Jiang, Long,Huang, Xuan,Chen, Dong,Yan, Hua,Li, Xueyuan,Du, Xuezhong
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- Intrinsically proton-conducting benzimidazole units tethered to polysiloxanes
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Polysiloxanes with pendant benzimidazole units have been prepared by free radical thiolene coupling reactions of 2-(2-benzimidazolyl)ethanethiol and vinyl-functional polysiloxanes. The latter polymers were prepared by anionic ring opening copolymerization of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclosiloxane and 1,3,5-hexamethylcyclosiloxane. Copolymers with different degrees of benzimidazole functionality were conveniently obtained by varying the monomer ratios. The coupling reaction was found to be very efficient, and the vinyl groups were completely consumed, as confirmed by NMR and FTIR spectroscopy. The glass transition temperature (Tg) of the benzimidazole functional copolymers increased dramatically with the benzimidazole content at low contents to reach a plateau value just above 50°C at a content of approximately 33 mol % benzimidazole functional siloxane residues in the copolymer. Conductivity measurements carried out at 60 and 140°C indicated that the level of polymer segmental mobility, and thus the Tg, was the most decisive parameter for the proton conductivity at low temperatures (60°C), while the benzimidazole concentration was more important at elevated temperatures (140°C). A conductivity of 7 × 10-6 S/cm was reached at 140°C by a polygiloxane carrying 57 mol % benzimidazolegrafted siloxane residues under completely anhydrous conditions.
- Persson, J. Christian,Jannasch, Patric
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- Synthesis and structural features of new cyclofunctionalized benzimidazoles
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The synthesis of new tricyclic derivatives having sulfur-containing six or seven-membered rings fused to the > edge of benzimidazole system, is reported. The stereochemical characteristics of thiazino- and thiazepinobenzimidazoles (4-7) are described
- Chimirri, Alba,Monforte, Anna Maria,Monforte, Pietro,Nicolo, Francesco,Rao, Angela,Zappala, Maria
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p. 613 - 620
(2007/10/03)
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- ACTIVITE ESTEROLYTIQUE DE COMPOSES ASSOCIANT UNE FONCTION THIOL ET UNE BASE HETEROCYCLIQUE. EXEMPLES DE PROCESSUS BIFONCTIONNEL
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The synthesis of 19 compounds associating a thiol function and a basic heterocycle (i.e. benzimidazole, pyridine, thiazole) is described.Their esterolytic activity towards para nitrophenyl acetate (PNPA) is compared with that of simple monofunctional thiols.The influence of the substituents and of the nature of the basic heterocycle shows that the apparition of a cooperative effect depends both on the relative pKa values (thiol and heterocyclic) and on the possibility of proton exchange via the heterocyclic moiety.Examples of bifonctional process are reported in the case of benzimidazolylmethanethiol compounds, due to a basic assistancce on the neutral form of the thiol function.
- Brembilla, Alain,Roizard, Denis,Lochon, Pierre
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p. 577 - 588
(2007/10/02)
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