STEP-BY-STEP SYNTHESIS OF LINEAR PENTAMANNOSYLTETRAPHOSPHATE VIA GLYCOSYL HYDROGENPHOSPHONATES

Step-by-step synthesis of linear (1-6)-linked methyl tetra(alpha-D-mannopyranosyl phosphate)-alpha-D-mannopyranoside was developed with the use of the hydrogenphosphonate method. Methyl 2,3,4-tri-O-acetyl-alpha-D-mannopyranoside served as first acceptor of the oligo(mannosyl phosphate) chain. Elongation cycle included coupling of 2,3,4-tri-O-benzoyl-6-O-dimethoxytrityl-alpha-D-mannopyranosyl H-phosphonate and a hydroxyl component in the presence of Me3CCOCl followed by oxidation and detritylation. 2,3,4,6-Tetra-O-benzoyl-alpha-D-mannopyranosyl H-phosphonate was employed in the final step. After complete deprotection the title oligomer was isolated in 30% overall yield.