Synthesis of 5-amino-4-sulfonamidoimidazole nucleosides as potential inhibitors of purine nucleotide biosynthesis, and of an imidazothiadiazine dioxide analogue of adenosine

5-Amino-4-sulfonamido-1-(ß-D-ribofuranosyl)imidazole 6 and two more complex sulfonamides, one of which (8) incorporates an L-aspartyl unit, have been prepared as potential inhibitors of the intermediate stages in the pathway for de novo biosynthesis of purine nucleotides. An intermediate in the preparation of 6 could be cyclized to give 5-(ß-D-ribofuranosyl)imidazo[4,5-e]-1,2,4-thiadiazine-1,1-dioxide 9, a novel analogue of adenosine and inosine, and a potential inhibitor of enzymes which effect reactions at C-6 of purine nucleosides or nucleotides.