RCAI-61, the 6′-O-methylated analog of KRN7000: its synthesis and potent bioactivity for mouse lymphocytes to produce interferon-γ in vivo

RCAI-61, the 6′-O-methylated analog of KRN7000, and six other analogs with modified 6′-position of the galactose moiety of KRN7000 were synthesized to examine their bioactivity for mouse lymphocytes. Methyl α-d-galactopyranoside was the starting material for RCAI-58, 61, 64, 83, 85, and 86, while RCAI-87 was prepared from methyl β-l-arabinopyranoside. Bioassay showed RCAI-61 to be a much more potent stimulant of mouse lymphocytes than KRN7000 and RCAI-56 to induce the production of a large amount of IFN-γ in vivo.