Synthesis of 8-(2"-hydroxyethoxy)adenosine-5',2"-phosphate derivative.

Reaction of 8-bromo-2',3'-O-isopropylidene-5'-O-(tetrahydropyran-2-yl) adenosine (Ib) with lithium 2-(tetrahydropyran-2-yloxy) ethoxide, followed by removal of the tetrahydropyran-2-yl groups, afforded 8-(2''-hydroxyethoxy)-2',3'-O-isopropylideneadenosine (II). Successive treatment of II with n-butyllithium and with methyl dichlorophosphate provided the 5',2''-(methyl phosphate) derivative (IIIa and IIIb).