S-Geranylated 2-Thiouridines of Bacterial tRNAs: Chemical Synthesis and Physicochemical Properties

Herein, we report the first synthesis of two recently discovered, prenylated 2-thiouridine derivatives, 5-methylaminomethyl-S-geranyl-2-thiouridine (mnm5geS2U) and 5-carboxymethylaminomethyl-S-geranyl-2-thiouridine (cmnm5geS2U). S-Geranylated 2-thiouridines were obtained by S-alkylation of the parent (c)mnm5S2U nucleosides suitably protected at their C5-alkylamino function. Comparative physicochemical studies of S2U, mnm5S2U, and cmnm5S2U and their S-geranylated derivatives revealed unique highly hydrophobic properties of the geranylated species and their increased C2-endo sugar ring puckering in comparison to their parent 2-thiouridines.