Synthesis Of β-D-Glcp-(1→3)-[β-D-Glcp-(1→6)]-β-D-Glcp-(1→3)-β-D-Glcp-(1→6)-[β-D-Glcp-(1→4)-β-D-Glcp-(1→3)]-β-D-GlcpOLauryl, an oligosaccharide with anti-tumor activity

A concise and effective synthesis of lauryl heptasaccharide 17 was achieved from the key intermediates lauryl 2,3,4,6-tetra- O-benzoyl-beta-D-galactopyranosyl-(1-->4)-2,3,6-tri-O-benzoyi-beta-D-glucopyranosyl-(1 --> 3)-2,4-di-O-benzoyl-beta-D-glucopyranoside (10) and isopropyl 2,4,6-tri-O-acetyl-3-O-allyl-beta-D-glucopyranosyl-(1-->3)-[2.3,4,6-tetra-O-benzoyl-beta-D-glucopyranosyl-(1-->6)]-2,4-di-O-acetyl-beta-D-glueopyranosyl-(1--> 3)-2,4,6-tri-O-acetyl-1-thio-beta-D-glucopyranoside (15). The key trisaccharide glycosyl acceptor 10 was constructed by coupling 2,3,4,6-tetra-O-benzoyl-beta-D-galactopyranosyl-(1-->4)-2,3,6-tri-O-benzoyl-alpha-D-glucopyranosyl trichloroacetimidate (3) with lauryl 6-O-acetyl-2,4-di-O-benzoyi-beta-D-glucopyranoside (9), followed by deacetylation. The thioglycoside donor 15 was obtained by condensation of 2,4,6-tri-O-acetyl-3-O-allyl-beta-D-glucopyranosyl-(1-->3)-[2,3,.4,6-tetra-O-benzoyl-beta-D-glucopyranosyl-(1-->6)]-2,4-di-O-acetyl-alpha-D-glucopyranosyI trichloroacetimidate (11) with isopropyl 4,6-O-benzylidene-1-thio-beta-D-glucopyranoside (12), followed by debenzylidenation and acetylation. A bioassay of the inhibition of S-180 noumenal tumors showed that lauryl heptasaccharide 17 could be employed as a potential agent for cancer treatment. (C) 2005 Elsevier Ltd. All rights reserved.