New Nucleoside−Sugar Conjugates: 6-N-Glycosyloxyphosphorylated Adenosine Derivatives as Partial Structures of Agrocin 84

We report the first successful synthesis of 6- N -[(glucofuranos-1-yloxy)phosphoryl]adenosine as a partial structure of Agrocin 84 via a two-step phosphorylation of 2‘,3‘,5‘-tri- O -benzoyladenosine with a 2,3,5,6-tetra- O -acetylglucofuranoside 1- O -phosphoramidite derivative that has a 2-(trimethylsilyl)ethyl group as the phosphate protecting group. A similar nucleoside−sugar conjugate, 6- N -[(ribofuranos-1-yloxy)phosphoryl]adenosine, was also synthesized. The stabilities of these 6- N -[(glycos-1-yloxy)phosphoryl]adenosine derivatives under acidic, basic, and thermal conditions are described. In particular, we found that the P−O bond of these sugar−nucleoside conjugates was selectively cleaved by treatment with 0.1 M NaOH to give 6- N -phosphoryladenosine, while acidic treatment gave directly adenosine with cleavage of the P−N bond.