| abstract |
Disclosed herein are protecting groups for exocyclic amino groups of the base cytosine for use in the synthesis of oligonucleotides and oligonucleoside phosphorothioates, the protecting groups being represented by the formula: -CO-(CH2)0-9-CH3. In a particularly preferred embodiment, the base cytosine is protected with acetyl (-CO-CH3), and the oligonucleotide or oligonucleoside phosphorothioate incorporating the protected cytosine is subjected to a cleavage/deprotection reagent comprising methylamine and ammonia. |