Synthesis of α-galactosyl ceramide and the related glycolipids for evaluation of their activities on mouse splenocytes

Phytosphingosine and its short-chain analog were efficiently synthesized with 19% overall yield in 10 steps, respectively, starting from an inexpensive d-lyxose. Galactosyl donors of sulfide and phosphite types bearing benzoyl protecting groups of 4- and 6-OH underwent glycosylation in excellent α-anomeric selectivity. A variety of α-galactosyl, fucosyl and glucosyl ceramides and serine-type lipids were prepared, and their activities involved in the proliferation of mouse splenocytes and the expression of cytokines were elucidated. Besides α-galactosyl ceramides, a galactosyl serine-type lipid also exhibited substantial effect on the expression of cytokines IFN-γ and IL-4.