Aryl h-phosphonates. 14. Synthesis of new nucleotide analogues with phosphonate-phosphate internucleosidic linkage

[reaction: see text] Aryl nucleoside H-phosphonates 3 and aryl nucleoside P-acylphosphonates 4, generated in situ from the appropriate H-phosphonate 1 and acylphosphonate monoesters 2, respectively, reacted rapidly in the presence of tertiary amines to produce in high yields the extended, pyrophosphate analogues, diaryl dinucleoside phosphonate-phosphate derivatives 6. These, depending on a substituent on the alpha-carbon of the phosphonate moiety, either underwent transformation into the dinucleoside phosphonate-phosphate 7 or afforded nucleoside H-phosphonates 8 and aryl nucleoside phosphate 9.