Carbohydrate conjugated rna agents and process for their preparation

Abstract

This disclosure relates to an improved process for the preparation of carbohydrate conjugates. The disclosure also relates to carbohydrate conjugated iRNA agents comprising these carbohydrate conjugates, which have improved purity and are advantageous for the in vivo delivery of the iRNA agents.

1 . A compound of formula (A) 
       
         
           
           
               
               
           
         
         wherein
 each occurrence of X is hydrogen or a hydroxy protecting group; 
 each occurrence of Y is an amine protecting group, (e.g., acetyl); 
 n is 0-20; 
 each occurrence of q, r and s is independently 1-7; 
 L is a linking group; and 
 R 1  is an iRNA agent; 
 
         wherein the compound of formula (A) is free or substantially free of one or more of
 (i) metal impurities, 
 (ii) each of the following two urea side products 
 
       
       
         
           
           
               
               
           
         
          and
 (iii) each of the following saccharide compounds 
 
       
       
         
           
           
               
               
           
         
       
     
     
         2 . The compound according to  claim 1 , wherein the compound of formula (A) contains no more than 0.5% of any individual urea side product or saccharide compound. 
     
     
         3 . The compound according to  claim 1 , wherein the compound of formula (A) contains no more than 0.2% of any individual urea side product or saccharide compound. 
     
     
         4 . The compound according to  claim 1 , wherein the compound of formula (A) contains no more than 1000 ppm of any individual metal. 
     
     
         5 . The compound according to  claim 1 , wherein the compound of formula (A) contains no more than 100 ppm of any individual metal. 
     
     
         6 . The compound according to  claim 1 , wherein the compound of formula (A) contains no more than 10 ppm of any individual metal. 
     
     
         7 . The compound according to  claim 1 , wherein the compound of formula (A) contains no more than 1 ppm of any individual metal. 
     
     
         8 - 21 . (canceled) 
     
     
         22 . A process for preparing a compound of formula (I): 
       
         
           
           
               
               
           
         
         wherein
 X is a hydroxyl protecting group; 
 Y is an amine protecting group; 
 Prt is a hydroxyl protecting group; 
 n is 0-15; 
 q, r and s are each, independently, 1-7; and 
    is a solid support; 
 
         said process comprising
 (1) treating a compound of formula II: 
 
       
       
         
           
           
               
               
           
         
         with a compound of formula III: 
       
       
         
           
           
               
               
           
         
         in the presence of a base to afford a compound of formula (IV): 
       
       
         
           
           
               
               
           
         
         wherein Z is an acid protecting group;
 (2) deprotecting Z in the compound of formula (IV), followed by coupling with a hydroxyl proline of formula (V): 
 
       
       
         
           
           
               
               
           
         
         
           (3) coupling the product of step (2) with succinic anhydride; and 
           (4) coupling the product of step (3) to a solid support to afford a compound of formula (I). 
         
       
     
     
         23 . The process of  claim 22 , wherein X is Bz or Ac. 
     
     
         24 . The process of  claim 22 , wherein Y is Ac. 
     
     
         25 . The process of  claim 22 , wherein n is 7; and q, r, and s are each 1. 
     
     
         26 . The process of  claim 22 , wherein Prt is a 4,4′-Dimethoxytrityl protecting group. 
     
     
         27 . A compound selected from
 (i) a compound of formula (VIII):   
       
         
           
           
               
               
           
         
       
       wherein
 A is a C 6 -C 14  alkylene linker, 
 each R is, independently, an acid protecting group, and 
 R x  is an acid protecting group; 
 (ii) a compound of formula (XII): 
 
       
         
           
           
               
               
           
         
       
       wherein
 Z is an acid protecting group, 
 n is 0-20, 
 each occurrence of q, r and s is independently 1-7, and 
 P is an amino protecting group with a sulfonic acid; 
 (iii) a compound of formula (II): 
 
       
         
           
           
               
               
           
         
       
       wherein
 Z is an acid protecting group, 
 n is 0-20, and 
 each occurrence of q, r and s is independently 1-7; and 
 (iv) a compound of formula (XIII): 
 
       
         
           
           
               
               
           
         
       
       wherein
 X is a hydroxyl protecting group, 
 Y is an amine protecting group, 
 Prt is a hydroxyl protecting group, 
 n is 0-15, and 
 q, r and s are each, independently, 1-7. 
 
     
     
         28 . The compound of  claim 27 , wherein the compound is a compound of formula (VIII): 
       
         
           
           
               
               
           
         
         wherein
 A is a C 6 -C 14  alkylene linker, 
 each R is, independently, an acid protecting group, and 
 R x  is an acid protecting group. 
 
       
     
     
         29 . The compound of  claim 27 , wherein the compound is a compound of formula (XII): 
       
         
           
           
               
               
           
         
         wherein
 Z is an acid protecting group, 
 n is 0-20, 
 each occurrence of q, r and s is independently 1-7, and 
 P is an amino protecting group with a sulfonic acid. 
 
       
     
     
         30 . The compound of  claim 27 , wherein the compound is a compound of formula (II): 
       
         
           
           
               
               
           
         
         wherein
 Z is an acid protecting group, 
 n is 0-20, and 
 each occurrence of q, r and s is independently 1-7. 
 
       
     
     
         31 . The compound of  claim 27 , wherein the compound is a compound of formula (XIII): 
       
         
           
           
               
               
           
         
         wherein
 X is a hydroxyl protecting group, 
 Y is an amine protecting group, 
 Prt is a hydroxyl protecting group, 
 n is 0-15, and 
 q, r and s are each, independently, 1-7.