mt-tRNA components: synthesis of (2-thio)uridines modified with blocked glycine/taurine moieties at C-5,1.

In this paper, we discuss the usefulness of reductive amination of 5-formyl-2,3-O-isopropylidene(-2-thio)uridine with glycine or taurine esters in the presence of sodium triacetoxyborohydride (NaBH(OAc)(3)) for the synthesis of the native mitochondrial (mt) tRNA components 5-carboxymethylaminomethyl(-2-thio)uridine (cmnm(5)(s(2))U) and 5-taurinomethyl(-2-thio)uridine (m(5)(s(2))U) with a blocked amino acid function. 2-(Trimethylsilyl)ethyl and 2-(p-nitrophenyl)ethyl esters of glycine and 2-(2,4,5-trifluorophenyl)ethyl ester of taurine were selected as protection of carboxylic and sulfonic acid residues, respectively. The first synthesis of 5-formyl-2,3-O-isopropylidene-2-thiouridine is also reported.