The 2'-deoxyribonucleoside phosphoramidite 8-Aza-7-deaza-dA (BA0239), also known as PPA CEP, features a nucleobase that is isosteric with adenine but offers a different pi-electron distribution and thus an altered dipole moment, resulting in stronger stacking interactions in oligonucleotides.⁽¹⁾ We also offer the ribonucleoside version, 8-Aza-7-deaza-A phosphoramidite (BA0267), for use in the synthesis of altered RNA oligonucleotides.

Ref:

1. Seela, F.; Kaiser, K. Helv. Chim. Acta 1988, 71, 1813-1823. Seela describes the N6-benzoyl version of the phosphoramidite of 2'-deoxy-8-aza-7-deaza-A. The N-(dimethylamino)methylidene version of the 2'-deoxy version is available from us.