α-Oligodeoxynucleotides containing 5-propynyl analogs of α-deoxyuridine and α-deoxycytidine: Synthesis and base pairing properties

Abstract

From propyne and 5-iodo-α,2-deoxyuridine, obtained by glycosylation, 5-propynyl-α,2'-deoxyuridine was synthesized following the procedure of Hobbs. One part was then transformed through displacement of its C4-triazolo derivative with ammonia into 5-propynyl-α,2'-deoxycytidine derivative. Finally, the corresponding α 5-propynyl nucleoside phosphoramidites were prepared, and 5-propynyl-α oligonucleotides (12-mer) with either phosphodiester and phosphorothioate were synthesized. The melting temperatures showed that duplexes with complementary DNA are stabilized between 0.65 and 1.2°C/mod, and duplexes with RNA are stabilized between 1.2 and 1.4°C/mod.