摘要 |
A process for preparing a conjugate which is an immunoglobulin or immunoglobulin fragment with an acylated difluoronucleoside linked to it, the acylated difluoronucleoside being of the formula <CHEM> R1 is hydrogen, C1-C4 alkyl, -COR3, or -COXCO-; R2 is hydrogen or -COXCO-; R4 is hydrogen, C1-C4 alkyl, amino, bromo, fluoro, chloro, or iodo; R3 is hydrogen or C1-C4 alkyl; X is a bond, C1-C10 straight chain alkylene, C2-C10 branched alkylene, C2-C10 alkenylene, C3-C10 alkynylene, C3-C6 cycloalkylene, phenylene, or hydroxy-substituted C1-C10 alkylene, and A is N or C-R4; provided that one and only one of R1 and R2 is -COXCO-. |