Pyrrolic Tripodal Receptors for the Molecular Recognition of Carbohydrates: Ditopic Receptors for Dimannosides |
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Authors: | Dr Oscar Francesconi Prof Cristina Nativi Dr Gabriele Gabrielli Matteo Gentili Marco Palchetti Beatrice Bonora Dr Stefano Roelens |
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Institution: | 1. Dipartimento di Chimica, Università di Firenze, Polo Scientifico e Tecnologico, 50019 Sesto Fiorentino, Firenze (Italy);2. Istituto di Metodologie Chimiche (IMC), Consiglio Nazionale delle Ricerche (CNR), Dipartimento di Chimica, Università di Firenze, Polo Scientifico e Tecnologico, Via della Lastruccia, 13, 50019 Sesto Fiorentino, Firenze (Italy), Fax: (+39)?055‐457‐3570 |
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Abstract: | Synthetic ditopic receptors, designed for the molecular recognition of dimannosides, have been prepared by bridging two monotopic units effectively recognizing mannosides with linkers of the appropriate size and flexibility, endowed with hydrogen‐bonding groups. Affinities toward the α and β glycosides of the biologically relevant Manα(1–2)Man disaccharide were measured by NMR spectroscopy and isothermal titration calorimetry (ITC) in polar organic media (30–40 % DMF in chloroform). Significant selectivities and affinities in the micromolar range were observed in most cases, with two newly designed receptors being the most effective receptors of the set, together with a distinct preference of the dimannosides for the (S) enantiomer of the receptor in all cases. A 3D view of the recognition mode was elucidated by a combined NMR spectroscopic/molecular modeling approach, showing the dimannoside included in the cleft of the receptor. Compared to the monotopic precursors, the ditopic receptors showed markedly improved recognition properties, proving the efficacy of the modular receptor design for the recognition of disaccharides. |
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Keywords: | binding carbohydrates mannosides molecular recognition synthetic receptors |
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