Synthesis of various substituted 5-methyluridines (xm5U) and 2-thiouridines (xm5s2U) via nucleophilic substitution of 5-pivaloyloxyrnethyluridine/2-thiouridine

5-Pivaloyloxymethyluridine and its 2-thio analogue have been utilized as convenient substrates for the synthesis of various 5-methyluridines (xm(5)U) and 5-methyl-2-thiouridines (xm(5)s(2)U). The pivaloyloxy group (OPiv) located at the pseudobenzylic position was effectively substituted with a series of nucleophiles: ammonia, primary and secondary amines including secondary cyclic amines, tetrabutylammonium salts of amino acids, an alkoxide and a thiolate. (C) 2015 Elsevier Ltd. All rights reserved.