EP3811977A1 — Method for synthesis of reactive conjugate clusters

USPTO Abstract

Provided herein are improved methods for the synthesis of reactive conjugate clusters and intermediates used in such methods. In particular, improvements are provided that enhance the synthesis of reactive conjugate clusters by reducing the number of synthetic steps required. The reactive conjugate clusters prepared using the improved methods don't include any transacylation impurities that are formed using existing methods. The improved methods also provide an increase in overall yield and a cost benefit over existing methods.The reactive conjugate cluster has the formula:(L-A-N(H)C(=O)-E-)<sub>m</sub>-B<sub>ga</sub>wherein:L is a ligand;A is C2 to C10 alkyl optionally interrupted with one or more groups selected from -O-, -N(H)- and C(=O);E is a single bond or C1 to C10 alkyl optionally interrupted with one or more groupsselected from -O-, -N(H)-and C(=O);B<sub>ga</sub> is a reactive branching group;m is from 2 to 6- and C(=O); m is from 2 to about 6;