RCAI-37, 56, 59, 60, 92, 101, and 102, cyclitol and carbasugar analogs of KRN7000: their synthesis and bioactivity for mouse lymphocytes to produce Th1-biased cytokines.

Cyclitol [RCAI-37 (1), 59 (5), 92 (7), and 102 (2)] and carbasugar analogs [RCAI-56 (3), 60 (4), and 101 (6)] of KRN7000 were synthesized through coupling reactions of the corresponding cyclitol or carbasugar derivatives with a cyclic sulfamidate (9) as the key step. Bioassay showed RCAI-56 (3, carbagalactose analog of KRN7000), 59 (5, 1-deoxy-neo-inositol analog), and 92 (7, 1-O-methylated 5) to be remarkably potent stimulants of mouse lymphocytes to produce Th1-biased cytokines, such as interferon-gamma, in vivo. RCAI-60 (4, carbafucose analog) and RCAI-101 (6, 6-O-methylated 3) showed strong bioactivity, on the other hands, RCAI-37 (1, myo-inositol analog) and 102 (2, neo-inositol analog) induced little cytokine production.