Synthesis of 9‐[(2‐hydroxy‐1‐phosphonylethoxy)ethyl]guanine, 1‐[(2‐hydroxy‐1‐phosphonylethoxy)ethyl]cytosine and 9‐[(2‐hydroxy‐1‐phosphonylethoxy)ethyl] adenine

The acyclic nucleoside phosphonate analogues, 9-[(2-hydroxy-1-phosphonylethoxy)ethyl]guanine 6, 1-[(2-hydroxy-1-phosphonylethoxy)ethyl]cytosine 7 and 9-[(2-hydroxy-1-phosphonylethoxy)ethyl]adenine 8, have been prepared by the coupling of a tosylate of the phosphonate side chain 12 with a purine or pyrimidine base followed by deprotection of the blocking groups.