Synthesis of C-glycosides related to glycero-β-d-manno-heptoses
摘要:
Reducing heptopyranoses of the D-glycero-D-manno- and L-glycero-D-manno-configuration were converted in good overall yields into beta-anomeric C-glycosides via condensation with pentane-2,4-dione, followed by sodium methoxide-induced enrichment of the beta-anomeric products and subsequent O-acetylation. The resulting 2-oxo-propyl glycosides were further transformed into separable similar to1:1 diastereomeric mixtures of (S)- and (R)-2-hydroxy derivatives. The configuration of the additional stereogenic centre was assigned on the basis of NMR data obtained from the corresponding Dale-Mosher esters. Finally, phosphorylation of the D-glycero-D-manno-heptose analogues using the phosphoramidite procedure and deprotection furnished the (S)- and (R)-2-phosphate derivatives in good yields. The compounds serve as substrate analogues for enzymes involved in bacterial ADP heptose biosynthesis and glycosyl transfer reactions. (C) 2004 Elsevier Ltd. All rights reserved.
Synthesis of C-glycosides related to glycero-β-d-manno-heptoses
摘要:
Reducing heptopyranoses of the D-glycero-D-manno- and L-glycero-D-manno-configuration were converted in good overall yields into beta-anomeric C-glycosides via condensation with pentane-2,4-dione, followed by sodium methoxide-induced enrichment of the beta-anomeric products and subsequent O-acetylation. The resulting 2-oxo-propyl glycosides were further transformed into separable similar to1:1 diastereomeric mixtures of (S)- and (R)-2-hydroxy derivatives. The configuration of the additional stereogenic centre was assigned on the basis of NMR data obtained from the corresponding Dale-Mosher esters. Finally, phosphorylation of the D-glycero-D-manno-heptose analogues using the phosphoramidite procedure and deprotection furnished the (S)- and (R)-2-phosphate derivatives in good yields. The compounds serve as substrate analogues for enzymes involved in bacterial ADP heptose biosynthesis and glycosyl transfer reactions. (C) 2004 Elsevier Ltd. All rights reserved.