FAST OLIGONUCLEOTIDE DEPROTECTION PHOSPHORAMIDITE CHEMISTRY FOR DNA-SYNTHESIS

A new set of base protecting groups for cyanoethylphosphoramidite nucleosides and supports has been developed which decreases the post-synthesis time requirements. The traditional purine amide protecting groups, which require 8-16 hours at 55°C for deprotection in ammonia, have been replaced with the dimethylformamidine group. Oligonucleotides made with the new reagents require only 1 hour at 55°C or 8 hours at room temperature for complete deprotection. Dialkylformamidine phosphoramidites exhibit enhanced resistance to depurination compared to the traditional, or even the phenoxyacetyl, phosphoramidites. © 1990.