Synthesis of Phosphonates and Oligodeoxyribonucleotides Derived from 2′‐Deoxyisoguanosine and 2′‐Deoxy‐2‐haloadenosines

Abstract

Abstract Oligonucleotides containing 2′‐deoxyisoguanosine ( 1 ) or 2‐chloro‐2′‐deoxyadenosine ( 2a ) have been prepared by solid‐phase synthesis. Suitably protected phosphonates 3a, 4a , and 4b as well as the phosphoramidite of 1 have been obtained from the nucleosides 1, 2a , or 2b via the (dimethylamino)methylidene derivatives 5–7 . 4,4′‐Dimethoxytrityl groups were introduced to yield the base‐protected derivatives 8–10 . Alternatively to the direct incorporation of 1 into oligonucleotides, they were also obtained by the photochemical conversion of a 2a residue within the oligonucleotide chain.