phosphoramidite and 2--deoxyadenosine

Adducts of C8-(N-acetyl)-arylamines and 2'-deoxyadenosine were synthesised by palladium-catalysed C--N cross-coupling chemistry. These 2'-dA adducts were converted into the corresponding 3'-phosphoramidites and site-specifically incorporated into DNA oligonucleotides, which were characterised by mass spectrometry, UV thermal-stability assays and circular dichroism. These modified oligonucleotides were also used in EcoRI restriction assays and in primer-extension studies with three different DNA polymerases. The incorporation of the 2'-dA lesion close to the EcoRI restriction site dramatically reduced the susceptibility of the DNA strand to cleavage; this indicates a significant local distortion of the DNA double helix. The incorporation of the acetylated C8-2'-dA-phosphoramidites into 20-mer oligonucleotides failed, however, because the N-acetyl group was lost during the deprotection process. Instead the corresponding C8-NH-2'-dA-modified oligonucleotides were obtained. The effect of the C8-NH-arylamine-dA lesion on the replication by DNA polymerases was clearly dependent both on the polymerase used and on the arylamine-dA damage.

Topics: Amines; Circular Dichroism; Deoxyadenosines; DNA Replication; DNA-Directed DNA Polymerase; Molecular Structure; Oligonucleotides; Organophosphorus Compounds; Temperature

Ionic liquids have been used in combination with ball milling on a range of chlorophosphoramidite reagents to phosphitylate nucleosides and 2-deoxynucleosides. The enhanced stability offered by the ionic liquid mediated processes combined with efficient mass transfer induced by ball milling has enabled excellent yields to be obtained even when using small dialkyl amino groups as well as the more commonly used diisopropylamino protection.

Topics: Deoxyadenosines; Hydrolysis; Ionic Liquids; Nucleosides; Organophosphorus Compounds; Solubility

The synthesis of phosphoramidites of C8-modified 2'-deoxyadenosine with carcinogenic arylamines p-anisidine and 4-aminobiphenyl is described. Two different methods were studied related to the glycon and base protection groups.

Topics: Amines; Carcinogens; Deoxyadenosines; DNA Adducts; Organophosphorus Compounds