2 '-O-(carbamoylmethyl)oligoribonucleotides

Fully modified oligonucleotides containing 2'-O-cyanomethylribonucleotides were synthesised on automated DNA synthesisers using protected 2'-O-cyanome thylribonucleoside-3'-O-phosphoramidite building blocks. The 2'-O-cyanometh yloligoribonucleotides were post-synthetically converted into 2'-O-carbamoy lmethyloligoribonucleotides during standard deprotection conditions with aq ueous ammonia. The complete conversion was proven using ion- exchange HPLC and MALDI mass spectrometry of the final oligomer. The 2'-O-carbamoylmethyl ribonucleotides showed an substantial increase the melting temperature (Tm) of duplexes with complementary RNA relative to the corresponding RNA homod uplex. Consequently these analogues should prove useful for a variety of an tisense applications. (C) 1999 Elsevier Science Ltd. All rights reserved.