Preparation of derivatives of inosine 5'-phosphorothioate for use in affinity chromatography

Abstract

In the paper the known methods of preparation of ribonucleoside 5'-phosphorothioates II are evaluated and an improved method of their synthesis is described, based on the reaction of 2',3'-O-ethoxymethyleneribonucleosides III with thiophosphoryl chloride in the presence of one equivalent of pyridine, and subsequent hydrolysis. Inosine 5'-phosphate and inosine 5'-phosphorothioate(IIc) were converted to 2',3'-O-cyclic ketals of levulinic acid Vb, VIb on reaction with ethyl levulinate and ethyl orthoformate and subsequent alkaline hydrolysis. O-(4-Aminophenyl)inosine 5'-phosphorothioate (IX) was prepared from 2',3'-O-isopropylideneinosine (VII) with O-(4-nitrophenyl)thiophosphoryldiimidazolide and subsequent catalytic hydrogenation of the O-(4-nitrophenyl)ester VIII formed.