Synthesis of heteroanalogues of disaccharides as potential inhibitors of the processing mannosidase Class I enzymes
摘要:
Three disaccharide analogues of alpha-D -Man-(l-->2)-alpha-D-Man-OMe in which the ring and/or glycosidic oxygen atoms have been replaced by sulfur have been synthesized as potential inhibitors of Class I mannosidase enzymes. Glycosylation of appropriately protected methyl alpha-D-mannopyranosides, having free alcohol or thiol functional groups at the 2-position, with 2,3,4,6-tetra-O-acetyl-5-thio-alpha-D-mannopyranosyl trichloroacetitmidate was selective for the synthesis of cr-linked disaccharides in the case of the 2-alcohols, but yielded an alpha/beta mixture in the case of the 2-thiol glycosyl accepters. A disaccharide containing a single sulfur in the linkage was synthesized by nucleophilic substitution of the 2-triflate of a methyl alpha-D-glucopyranoside derivative by the thiolate anion of 2,3,4,6-tetra-O-acetyl-1-thio-alpha-D-mannopyranose. Protecting groups were removed by standard methods to give the free heterosubstituted disaccharides. (C) 1998 Elsevier Science Ltd. All rights reserved.