The Synthesis of Some Epoxyalkyl b-C-Glycosides as Potential Inhibitors of b-Glucan Hydrolases

Abstract

The treatment of tetra-O-benzyl-D-glucono-1,5-lactone with various alkenylmagnesium halides gave the intermediate lactols which, upon reduction (Et₃SiH/BF₃) and protecting group manipulation, yielded alkenyl tetra-O-acetyl-β-D-C-glucopyranosides in good yield. These β-D-C-glucosides were precursors of the epoxyalkyl β-D-C-glucopyranosides, themselves putative inhibitors of b-glucan hydrolases. Similar additions of Grignard reagents to per-benzylated cellobionolactone were not as successful in yielding epoxyalkyl β-C-cellobiosides. The addition of Grignard reagents to 1,2-anhydro-3,4,6-tri-O-benzyl-α-D- glucose offers a viable alternative route to the prop-2-enyl β-D-C-glucoside, but not to the but-3-enyl and pent-4-enyl counterparts. Likewise, the addition of Grignard reagents to a 1,2-anhydro cellobiose gave disappointing results. Preliminary results are reported for a novel approach to alkenyl β-D-C-glucosides by the alkylation of nitromethyl β-D-C-glucosides.