The thiourea group has been exploited to link two or four carbohydrate units at the upper rim of tetrapropoxycalix[4]arene derivatives in the cone conformation. Two synthetic methodologies were used, the first one consisting of the condensation of di- and tetraminocalix[4]arenes with the isothiocyanate of monosaccharides in dry CH2Cl2 at room temperature and the second one exploiting the condensation of an aminolactoside with a calixarene isothiocyanate. The first method allows the glycoconjugates to be obtained in 75-80% overall yields. The difunctionalised derivatives exist in a closed flattened cone conformation in CDCl3 and CD3OD due to the formation of intramolecular hydrogen bonds involving the thiourea groups which are broken in DMSO-d(6) to give an open flattened cone conformation. The thiourea groups act not only as linkers but also as binding units for anionic substrates as evidenced by solution H-1 NMR and ESI-MS experiments. Turbidimetric analysis indicates that the tetraglucoside and tetragalactoside clusters give specific interactions with Concanavalin A (Con A) and peanut lectin (PNA), respectively Both features show that the neoglycoconjugates could also be used as site specific molecular delivery systems.

Thiourea-linked upper rim calix[4]arene neoglycoconjugates: synthesis, conformations and binding properties / Sansone, Francesco; Casnati, Alessandro; E., Chierici; Ungaro, Rocco. - In: ORGANIC & BIOMOLECULAR CHEMISTRY. - ISSN 1477-0520. - 1:(2003), pp. 1802-1809. [10.1039/b301595e]

Thiourea-linked upper rim calix[4]arene neoglycoconjugates: synthesis, conformations and binding properties

SANSONE, Francesco;CASNATI, Alessandro;UNGARO, Rocco
2003-01-01

Abstract

The thiourea group has been exploited to link two or four carbohydrate units at the upper rim of tetrapropoxycalix[4]arene derivatives in the cone conformation. Two synthetic methodologies were used, the first one consisting of the condensation of di- and tetraminocalix[4]arenes with the isothiocyanate of monosaccharides in dry CH2Cl2 at room temperature and the second one exploiting the condensation of an aminolactoside with a calixarene isothiocyanate. The first method allows the glycoconjugates to be obtained in 75-80% overall yields. The difunctionalised derivatives exist in a closed flattened cone conformation in CDCl3 and CD3OD due to the formation of intramolecular hydrogen bonds involving the thiourea groups which are broken in DMSO-d(6) to give an open flattened cone conformation. The thiourea groups act not only as linkers but also as binding units for anionic substrates as evidenced by solution H-1 NMR and ESI-MS experiments. Turbidimetric analysis indicates that the tetraglucoside and tetragalactoside clusters give specific interactions with Concanavalin A (Con A) and peanut lectin (PNA), respectively Both features show that the neoglycoconjugates could also be used as site specific molecular delivery systems.
2003
Thiourea-linked upper rim calix[4]arene neoglycoconjugates: synthesis, conformations and binding properties / Sansone, Francesco; Casnati, Alessandro; E., Chierici; Ungaro, Rocco. - In: ORGANIC & BIOMOLECULAR CHEMISTRY. - ISSN 1477-0520. - 1:(2003), pp. 1802-1809. [10.1039/b301595e]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11381/1458296
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