A useful route is described for obtaining Z and E unsaturated alkylating agents 3 and 4. Coupling 6-azauracils 5 and 6 with unsaturated alkylating agent followed by the deprotection with H+ resin gave acyclonucleosides 11-14 in good overall yields. Unsaturated acyclonucleosides phosphonates 19 and 20 were prepared using potassium carbonate as base and 4-bromobut-2-enyl diethyl phosphonate 16 as the alkylating agent. The introduction of a propargyl group at the N-3 position of acyclonucleosides 7, 8 17, 18, 19, and 20 was achieved using potassium carbonate in DMF.
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