The condensation of amine (I) with 2,2-dimethylsuccinic anhydride (II) afforded amide (III). This was then coupled with azidothymidine (IV) using DCC and DMAP to furnish the title compound.
The condensation of azidothymidine (I) with 2,3-dimethylsuccinic anhydride (II) afforded amide (III). This was then coupled with amine (IV) using DCC and HOBt to furnish the title compound.