Oligodeoxynucleotides containing 2'-deoxy-1-methyladenosine and Dimroth rearrangement

2'-Deoxy-1-methyladenosine was incorporated into synthetic oligonucleotides by phosphoramidite chemistry. Chloroacetyl protecting group and controlled anhydrous deprotection conditions were used to avoid Dimroth rearrangement. Hybridization studies of intramolecular duplexes showed that introduction of a modified residue into the loop region of the oligonucleotide hairpin increases the melting temperature. It was shown that modified oligonucleotides may be easily transformed into oligonucleotides containing 2'-deoxy-N6-methyladenosine.