Scheme 3.

Synthesis of Acyclic Nucleotide Derivatives Containing an Amide Bond^a

^a Reagents: (i) (Ph)₃P, CBr₄, 25 °C, 12 h, 52%; (ii) P(OCH₃)₃, 80 °C, 6 h, 94%; (iii) Pd/C, H₂, 25 °C, 1 h, 100%; (iv) NaH, BrCH₂COOEt, 25 °C, 12 h, 82%; (v) 1 N NaOH, 25 °C, 1 h, 83%; (vi) 4-nitrophenol, EDAC, DMAP, 25 °C, 2 h, HN(CH₂CH₂OH)₂, 25 °C, 12 h, 36%; (vii) LDA, tetrabenzylpyrophosphate, −78 °C, 0.5 h, 0 °C, 2 h, 94%; (viii) BCl₃, anisole, −78 °C, 1 h, 0 °C, 4 h, 28%; (ix) 38, EDAC, 25 °C, 12 h, 82%; (x) TMS-Br, 25 °C, 12 h, 45%.