Synthetic Studies on Selectin Ligands/Inhibitors: Synthesis and Biological Activity of the Sulfated and Phosphorylated Multivalent β-D-Galactopyranosides Containing Fatty Alkyl Residues1 2

Abstract

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, A. Hasegawa and M. Kiso, J. Carbohydr. Chem., in press.