Further studies with adenosine 5′-dithiophosphoromorpholidate. A convenient preparation of nucleoside phosphorodithioates by a ‘triester’ approach

Adenosine 5′-dithiophosphoromorpholidate 1c reacts with orthophosphate to give adenosine 5′-(α,α-dithio)diphosphate 3c but is not converted into adenosine 5′-phosphorodithioate 2c by acidic hydrolysis. A new approach to the synthesis of nucleoside phosphorodithioates is described.