PARTIAL PROTECTION OF CARBOHYDRATE-DERIVATIVES .31. AN EFFICIENT METHOD FOR THE SYNTHESIS OF [4-N-15]CYTIDINE, 2'-DEOXY[4-N-15]CYTIDINE, [6-N-15]ADENOSINE, AND 2'-DEOXY[6-N-15]ADENOSINE DERIVATIVES

Nucleophilic substitution reactions of -azolyl-1-beta-D-ribofuranosyl- pyrimidin-2(1H)-one and 6-azolyl-9-beta-D-ribofuranosyl-9H-purine deri vatives, which were converted from uridine and inosine, with [N-15]pht halimide in the presence of triethylamine or DBU gave N-4-phthaloyl[4- N-15]cytidine and N-6-phthaloyl[6-N-15]- adenosine derivatives, respec tively, in high yields. Similar reactions of those azolyl derivatives with succinimide afforded N-4-succinylcytidine and N-6-succinyladenosi ne derivatives in high yields. The corresponding 2'-deoxyribonucleosid es were also synthesized efficiently through the same procedure.