Abstract
The side reaction of inter-ribonucleotide bond cleavage occuring during ammonia treatment for deprotection of support bound 2′-O-trialkylsilyl protected synthetic RNA has been assessed by analysis of a series of 15 mers of sequence T4XT10 where x is rA, rC, rG and U. Data derived from HPLC analysis of the products showed, in all cases, cleavage by the anhydrous ammonia to be dramatically reduced compared to that with ethanolic concentrated aqueous ammonia. The anhydrous reagent also gave improved product quality when used in the synthesis of a 50 residue sequence. Complete cleavage of exocyclic amine protection groups with the anhydrous reagent was confirmed by RNAse T2 digests.