Cyclic diacyl groups for protection of the N6-amino group of deoxyadenosine in oligodeoxynucleotide synthesis.

Three kinds of substituted phthaloyl groups and a succinyl group were introduced onto the N6-amino function of deoxyadenosine derivatives. Among them, the succinyl group was found to be the most effective for prevention of depurination upon detritylation in acidic media and the most stable in basic media. Protection of the N6-amino function of 5'-O-dimethoxytrityldeoxyadenosine and introduction of a succinate linker into the 3'-hydroxyl were achieved simultaneously by a one-step reaction with succinic anhydride. A tetradeoxyribonucleotide, dTpTpTpA containing a 3'-terminal deoxyadenosine was successfully synthesized on a polystyrene support via the phosphotriester method.