Chemical synthesis and properties of 5-taurinomethyluridine and 5-taurinomethyl-2-thiouridine

Unique taurine-containing uridine derivatives, 5-taurinomethyluridine (τm₅U) and 5-taurinomethyl-2-thiouridine (τm ⁵S²U), which were discovered in mammalian mitochondrial tRNAs, exist at the first position of the anticodon. In this paper, we report the first efficient synthesis of τm⁵U and τm ⁵S²U and describe their physicochemical properties. These modified ribonucleosides were synthesized by the reaction of 5-substituted uridine derivatives with a tetrabutylammonium salt of taurine that is highly reactive and wellsoluble in common organic solvents. UV and ¹H NMR spectrometric studies revealed the structural properties of the taurine-containing base moieties and the sugar conformations of these modified ribonucleosides.