SummaryThe acid-catalyzed fusion of dimethyl imidazole-4,5-dicarboxylate (7) with I-O-acetyl-2,3,~-tri-O-benzoyl-~-~-ribofuranose (6) provided dimethyl 1 -(2,3,5-tn-O-benzoyl-~-~-ribofuranosyl)imidazole-4,5-dicarboxylate (11) as the major product together with some a-anomer (13). The 8-anomer (11) was obtained as the only product when the trimethylsilyl derivative (9) of 7 was condensed with 6 in the presence of stannic chloride. Nucleoside 11 was treated with ammonia, and various primary amines to provide l-~-~-ribofuranosylimidazole-4,5-dicarboxarnide (5) and N , N'-disubstituted dicarboxamides (18-26) respectively. The synthesis of 1 -a-(33) and 1 -~-~-arabinofuranosylimidazole-4, 5-dicarboxamide (34), is also described. The conformation of 5, as studied by 'H-and I3C-NMR.-spectroscopy, was shown to be very similar to that of adenosine.The oxidation of the 2', 3'-O-isopropylidene derivative (15) of 5 with potassium permanganate or chromic oxide, followed by deprotection, or the direct oxidation of 5 with oxygen in the presence of platinum catalyst, led to the corresponding 5'-carboxylic acid 36. This was further converted into esters (37 and 38) and arnides (39-42).Treatment of some nucleosides with fuming nitric acid in oleum at -30" yielded the nitric acid esters 43-51. Beside the nitration of their sugar residues, one of the imidazolecarboxamide functions in nucleosides 46-51 and both N-methylcarboxamide functions in 44 were nitrated. Finally, reaction of the N , "-dimethyl-N, N'-dinitrodicarboxamide 44 with alkyl-und aralkylamines, afforded the N, N'-dialkyl-and N , N'-diaralkyldicarboxamides 52-56.