Add time:08/28/2019         Source:sciencedirect.com

The synthesis of the title tetrasaccharide glycoside 38 is reported. p-Nitrophenyl endo-3,4-O-benzylidene-6-deoxy-α-l-talopyranoside (4, 3-O-acetyl-2,4-di-O-benzyl-α-l-rhamnopyranosyl trichloroacetimidate (7), methyl 3-O-acetyl-4-O-benzyl-2-O-methyl-1-thio-β-l-fucopyranoside (15) 3-O-acetyl-4-O-benzyl-2-O-methyl-α-l-fucopyranosyl bromide (16), and ethyl 3-O-acetyl-4-O-benzyl-2-O-methyl-1-thio-α-d-rhamnopyranoside (33) were prepared as intermediates. Compound 4 was glycosylated with imidate 7 as well as with methyl 3-O-acetyl-2,4-di-O-benzyl-1-thio-α-l-rhamnopyranoside (9), affording the same disaccharide derivative 8. Deacetylation of 8 gave crystalline 17. Condensation of 17 with both fucosyl donors 15 and 16 yielded the same trisaccharide derivative 18 stereoselectively. Compound 18 was also prepared by the coupling of 4 with disaccharide glycosyl donor 20. After deacetylation of 18 (→ 34), methyl triflate-promoted glycosylation with compound 33 resulted in tetrasaccharide 35. Conversion of the p-nitrophenyl group of 35 into the p-trifluoroacetamidophenyl group (→ 36) and removal of the protecting groups gave the title tetrasaccharide glycoside 38.

We also recommend Trading Suppliers and Manufacturers of 3-deoxy-8-O-(3-O-rhamnopyranosyl-rhamnopyranosyl)-manno-octulosonate (cas 111070-81-6). Pls Click Website Link as below: cas 111070-81-6 suppliers