Immunomodulatory α‐Galactoglycosphingolipids: Synthesis of a 2′‐O‐Methyl‐α‐Gal‐GSL and Evaluation of Its Immunostimulating Capacity

Abstract

AbstractThe total synthesis of 1‐2‐docosanoylamino‐O‐(2‐O‐methyl‐α‐D‐galactopyranosyl)‐1,3,4‐octadecanetriol (2), a 2′‐methoxy analog of the immunostimulating α‐galactoglycosphingolipid 1, is reported. Stereoselective α‐glycosylation of the azido precursor of sphingosine was successfully performed for the first time using an improved Mukaiyama reaction. When assayed in a 72 h splenocyte proliferation test, compound 2 was significantly less stimulatory than the non‐methylated compound 1, suggesting that the galactose 2‐OH group is essential for the immunostimulatory activity of α‐Gal‐GSLs. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)