Aminooxy functionalized oligonucleotides: Preparation, on-support derivatization, and postsynthetic attachment to polymer support

Three novel phosphoramidites, each bearing a phthaloyl-protected aminooxy t ail, were prepared and applied in automated oligonucleotide synthesis. Afte r chain assembly, the phthaloyl protection was removed with hydrazinium ace tate. Normal succinyl linker turned to be stable under these conditions, an d hence the support-bound oligonucleotide could be converted to a pyrene ox ime conjugates by reacting with pyrene carbaldehyde or cis-retinal. Standar d ammonolytic deprotection then released the deprotected conjugate in solut ion. Alternatively, the crude aminooxy-tethered oligonucleotide was immobil ized to microscopic polymer particles by reacting the aminooxy function wit h the particle-bound aldehyde or epoxide groups. These immobilized oligonuc eotides were shown to serve properly as probes in a mixed phase hybridizati on assay.