Synthetic Studies on Selectin Ligands/Inhibitors: Synthesis and Biological Activity of the Sulfated and Phosphorylated Multivalent β-D-Galactopyranosides Containing Fatty Alkyl Residues

Ten sulfated and three phosphorylated β-D-galactopyranoside dimers and one sulfated β-D-galactopyranoside trimer containing fatty alkyl residues in place of ceramide have been synthesized. The coupling of 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl bromide (2) with branched fatty alkyl diols and a triol (1a-1j) using mercury bromide as an activating agent gave the corresponding parent glycolipids (4a-4j) in good yields. Regioselective sulfation of these parent glycolipids through the dibutylstannylene acetals produced the target sulfated glycolipids, 3-sulfate (5a-5j) while stepwise phosphorylation with dibenzyloxy(diisopropylamino) phosphine gave the phosphorylated glycolipids, 3,4-bisphosphate (9e, g, i). The synthetic glycolipids were assayed for their ability to block the adhesion of HL-60 cells to immobilized P-, L- and E-selectin. 1. Dedicated to the memory of Professor Akira Hasagawa. 2. Synthetic studies on sialoglycoconjugates, Part 102. For Part 101, see Y. Makimura, H. Ishida, A. Kondo...