Nucleotides. Part LV . Synthesis and application of a novel linker for solid‐phase synthesis of modified oligonucleotides

Various bifunctional amino‐protecting groups such as the phthaloyl, succinyl, and glutaryl group were investigated as potential linker molecules for attachment to solid‐support materials. Pentane‐1,3,5‐tricarboxylic acid 1,3‐anhydride ( 16 ) offered the best properties and reacted with the amino groups of differently sugar‐protected adenosine (see 20 and 22 ), cytidine (see 29 ), and guanosine derivatives (see 32 ) to the corresponding 2‐(2‐carboxyethyl)glutaryl derivatives 23 , 24 , 30 , and 33 . The usefulness of the new linker‐type molecules was demonstrated by the solid‐support synthesis of the potentially antivirally active 3′‐deoxyadenylyl‐(2′–5′)‐2′‐adenylic acid 2′‐{2‐[(adenin‐9‐yl)methoxy]ethyl} ester ( 38 ) starting from the 2′‐end with N 6 , N 6 ‐[2‐(2‐carboxyethyl)glutaryl]‐9‐{{2‐[(4,4′‐dimethoxytrityl)ethoxy]methyl}adenine ( 12 ).