Synthesis of pseudonucleosides containing chiral sulfahydantoins as aglycone (II)

A series of chiral sulfahydantoins have been synthesized by alkaline cyclization starting from N-sulfamylaminoacid methyl esters. Regioselective glycosylation of these pseudopyrimidic heterocycles was carried out with a benzyl protecting group on the N-sulfonylcarbamic position. Best glycosylation results were obtained by preliminary silylation of sulfahydantoins, and their condensation with a tetracylribofuranose which yielded the pseudonucleosides in a beta-anomeric configuration.