Scheme 4 depicts the synthesis of the adenine dinucleosides 14–16 from the intermediate NH-linked dinucleoside 20 (Scheme 2). The reaction of 4-chlorobenzenesulfonyl chloride with 20 in the presence of NEt3 [31,32] followed by a TFA treatment yielded 14. The treatment of 20 with 4-chloro-3-nitrobenzaldehyde or 4-chlorobenzaldehyde and sodium triacetoxyborohydride, followed by the removal of protective groups in acidic conditions resulted in dinucleosides 15 and 16, respectively. It is noteworthy that this reductive amination conducted at 40 °C increased the yields to 71% and 81%, respectively.