Post-synthetic transamination at position N4 of cytosine in oligonucleotides assembled with routinely used phosphoramidites

摘要

The commercially available and cheap nucleotide phosphoramidites are routinely used for the oligo-nucleotide (ODN) assembly. T, isobutyryl-dG (~(iBu)dG), benzoyl-dA (~(Bz)dA). acetyl-dC (~(Ac)dC) and benzoyl-dC (~(Bz)dC) derivatives are sufficient to produce orthogonally protected ODNs. Clean and efficient (ca. 30%-70% yield) post-synthetic amination of an ODN assembled with such phosphoramidites was selectively achieved at the N4 position of a singly introduced ~(Bz)dC. Such a method represents a novel and cheap strategy for the user-friendly post-modification of oligonucleotides at the internal position.