Synthesis of [5'-11C]ribonucleoside and -2'-deoyribonucleoside derivatives from D-ribose.

An approach to the synthesis of 2'-deoxy[5'-13C]ribonucleosides was achieved by the coupling reaction of a nucleic acid base derivative with D-[5-13C]ribose derivative (8). Compound 8 was derived from D-ribose (1) by way of methyl 2,3-di-O-benzyl(Bn)-D-ribofuranoside (2), 2,3-di-O-Bn-D-ribose diethyl dithioacetal (3), 2,3-di-O-Bn-D-ribose dibenzyl acetal (4), and 4-aldehydo-2,3-di-O-Bn-D-erythrose dibenzyl acetal (5), which was then successively subjected to Wittig reaction using Ph3P13CH3I-BuLi, highly stereoselective hydroxylation with OsO4 to give 2,3-di-O-Bn-D-ribose dibenzyl acetal (7), debenzylation with H2-Pd/C. The resulting 8 was subjected to coupling reaction with a nucleic acid base to give [5'-13C]ribonucleosides. The products were derived into the corresponding 2'-deoxy[5'-13C]ribonucleoside derivatives by the established manner.