2' Modified oligonucleotides

Abstract

Oligomers which have substituents on the 2′ position are resistant to oligonucleases and furthermore can be derivatized to deliver reagents or drugs, to carry label, or to provide other properties.

1 - 63 . (canceled)  
     
     
         64 . A mixed sequence oligonucleotide having the formula:  
       
         
           
           
               
               
           
         
       
       or a salt thereof, wherein: 
 each B independently is a protected or unprotected purine or pyrimidine base in the β-anomeric configuration;  
 W 3  and W 4  are each independently H, PO 3   −2 , a protecting group, or an intermediate moiety in the formation of an internucleotide link which when reacted with the appropriate —OH results in Z;  
 n is an integer of 1-200;  
 each Z is independently is P(O)O, P(O)S or P(O)N(R) 2 ;  
 each R is independently H or alkyl (C 1-6 );  
 each A is H, OH, O—Pr wherein Pr is a protecting group, or X—Y wherein: 
 X is O, S or NH; and  
 Y is a bivalent bridging moiety, including methylene groups of the formula:  
   —(CH 2 ) nn —,  wherein nn is 1, 2, 3 or 4,    
 
 and at least one A is X—Y.