abstract |
Compounds of structure (I) in which R4, R5, R6 and R7 individually represent H, OH or C1-C18 O-acyl, and R3 represents H, C1-C18 acyl or (1); or R5 and R7 represent H or OH, R6 represents H and, together, R3 and R4 represent (2); and X represents = O or = S; Y represents -OH, -SH, -NH2 or a halogen; and Z represents H, -NH2, -OH or a halogen, the halogen being Cl or Br; or a pharmaceutically acceptable salt thereof are useful as antiviral, anti-tumor and anti-metastatic agents as well as agents for strengthening the immune system. |