Rapid and efficient synthesis of α(1–2) mannobiosides






José J. Reina, Antonio Di Maio, Javier Ramos-Soriano, Rute C. Figueiredo and Javier Rojo

Org. Biomol. Chem. 2016 DOI: 10.1039/c6ob00083e

α(1,2)mannobiosides with different substituents at the reducing end have been synthesized by a common strategy using benzoyls as the permanent protecting groups and an acetyl as the orthogonal protecting group at position C2 of the glycosyl acceptor. The new synthetic strategy has been performed remarkably reducing the number of purification steps, the time of synthesis (less than 72 hours) and improving the overall yield at least three times with respect to the best procedure described in the literature at the moment. Additionally, this protecting group strategy is compatible with the presence of azido groups and the use of Cu catalyzed azide alkyne cycloaddition (CuAAC) also called “click chemistry” for conjugating the α(1–2)mannobiosides to different scaffolds for the preparation of mannosyl multivalent systems.

Picture Paper Antonio




Monitoring Glycan-Protein Interactions by NMR Spectroscopic Analysis: A Simple Chemical Tag That Mimics Natural CH- Interactions






Luis P. Calle, Begoña Echeverria, Antonio Franconetti, Sonia Serna, M. Carmen Fernández-Alonso, Tammo Diercks, F. Javier Cañada, Ana Ardá, Niels-Christian Reichardt, Jesús Jiménez-Barbero

Chemistry A European Journal, 2015, 21 / 32 (11408-11416), 10.1002/chem.201501248


Detection of molecular recognition processes requires robust, specific, and easily implementable sensing
methods, especially for screening applications. Here, we propose the difluoroacetamide moiety (an acetamide bioisoster) as a novel tag for detecting by NMR analysis those glycan–protein interactions that involve N-acetylated sugars. Although difluoroacetamide has been used previously as a substituent
in medicinal chemistry, here we employ it as a specific sensor to monitor interactions between GlcNAc-containing glycans and a model lectin (wheat germ agglutinin). In contrast to the widely employed trifluoroacetamide group, the difluoroacetamide tag contains geminal 1H and 19F atoms that allow both 1H and 19F NMR methods for easy and robust detection of molecular recognition processes involving
GlcNAc- (or GalNAc-) moieties over a range of binding affinities. The CHF2CONH- moiety behaves in a manner that is very similar to that of the natural acetamide fragment in the involved aromatic-sugar interactions, providing analogous binding energy and conformations, whereas the perfluorinated CF3CONH- analogue differs more significantly.