NUCLEOSIDE S-ALKYL PHOSPHOROTHIOATES .2. PREPARATION AND CHEMICAL AND ENZYMATIC PROPERTIES

Nucleoside 5′-S-ethyl phosphorothioates, prepared by condensation of pyridinium S-ethyl phosphorothioate with a variety of suitably protected nucleosides using dicyclohexylcarbodiimide (DCC) as the condensing agent, have been converted into the corresponding nucleotides by treatment with aqueous iodine or sodium periodate. The protecting groups employed were found to be stable under these conditions. This procedure represents an extremely mild method for the phosphorylation of nucleosides. The nucleoside 5′-S-ethyl phosphorothioates have been used as intermediates in the preparation of a wide variety of nucleotide derivatives, including methyl, β,β,β-trichloroethyl, and p-nitrophenyl esters, dinucleoside monophosphates, a morpholidate, and di- and triphosphates. All of these reactions involve the cleavage of the P-S bond using iodine and the appropriate nucleophile. The enzymatic susceptibilities of the nucleoside S-ethyl phosphorothioates have also been studied. © 1969, American Chemical Society. All rights reserved.