Stereoselective synthesis of 2-thioglycosides of N-acetylneuraminic acid

Article abstract of DOI:10.1016/0008-6215(89)80054-0

Treatment of methyl 5-acetamido-2,4,7,8,9-penta-O-acetyl-3,5-dideoxy-β-D-glycero-D-galacto-2-nonulopyranosonate (1) severally with thiophenol, phenylmethanethiol, and ethanethiol in the presence of boron trifluoride etherate gave the corresponding 2-thio-β-glycosides 3-5.Treatment of methyl (5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-β-D-glycero-D-galacto-2-nonulopyranosyl chloride)onate (2) severally with thiophenol in the presence of N,N-di-isopropylethylamine, O-ethyl S-potassium dithiocarbonate, and O-ethyl S-potassium thiocarbonate gave the corresponding 2-thio-α-glycosides, 7, 10, and 11, of which 10 was converted into the ethyl 2-thio-α-glycoside 9 on heating with N,N-dimethylformamide-sodium iodide.The phenyl 2-thioglycosides 3 and 7 were converted into the corresponding sulfones.