Nucleosides and Nucleotides. Part 7. Four dithymidine monophosphates with different anomeric configurations, their synthesis and behaviour towards phosphodiesterases

The four isomeric dithymidine monophosphates βT d ‐βT d ( 1 ), αT d ‐βT d (2), βT d ‐αT d ( 3 ) and αT d ‐αT d ( 4 ), differing only by the anomeric configurations of the nucleoside units, were prepared from the suitably protected nucleosides and nucleotides. The four dinucleoside monophosphates were tested as substrates of snake venom phosphodiesterase and spleen phosphodiesterase. Both enzymes accept all four compounds as substrates, however, the rate of the hydrolysis is considerably smaller if the enzymic attack takes place at the α‐nucleoside moiety of the dinucleoside monophosphate.