Synthesis of 3-amido-3-deoxy-beta-D-talopyranosides: all-cis-substituted pyranosides as lectin inhibitors

3-Deoxy-3-amino-beta-D-talopyranosides have been synthesized for the first time. The amines were obtained from galactopyranosides through 2,3-anhydrogulosides that were opened to idosides followed by an oxidation/reductive amination sequence. From the amines, 11 corresponding 3-deoxy-3-arylamido-beta-talopyranosides have been synthesized and evaluated as inhibitors against galectin-1, -2, -3, -4C, -4N, -7, -8N and -9N. The synthesized talosamides showed selectivity for Galectin-4C with three of the mono-saccharides having dissociation constants at around 100 mu M against the lectin, which is more than two orders of magnitude better than methyl beta-galactoside and significantly better than the previous best galectin-4C monosaccharide inhibitor. (C) 2011 Elsevier Ltd. All rights reserved.