Solid phase synthesis of Carbon-14 labelled oligonucleotides
This paper describes the syntheses of a series of 14Clabelled phosphorothioate 2’-methoxy (2’-OMe) RNAscontaining two 14C labels. The labelled oligonucleotideswere prepared by solid phase synthesis utilizing an AKTAOligoPilot 100 synthesizer and 2’-O-methyluridine[2-14C].Trityl-on purifi cation was performed using preparativeanion exchange HPLC and on-column detritylation. Inaddition, a 14C labelled phosphorothioate 2’-OMe RNAsequence having a C6-amino spacer at the 5’ terminuswas synthesized and post-synthetically conjugated toa reporter group via an amide linkage. The purifi edphosphorothioate 2’-OMe RNAs were desalted utilizing aMillipore stir cell apparatus. These phosphorothioate 2’-OMe RNAs contained between 20 to 22 bases and wereobtained on a scale of 100-200 mg with a specifi c activitiesof 10-15 μCi/mg and a radiochemical purity of greaterthan 95 area percent.