| 摘要 |
<p>1. A compound of formula II: <CHEM> in which X is an acyl group of formula -R - @ - wherein R is an aliphatic or aromatic residue, A is a bridging group comprising at least one heteroatom selected from oxygen sulphur and nitrogen, in which the nitrogen is optionally substituted by C1-6 alkyl, B is a hydrophilic linking group, and W represents a group capable of reacting directly with the amino acid side chain of a protein or protein attachment group, Z is a counter anion and R1 to R4 are each independently hydrogen or an electron withdrawing moiety.</p> |
