Glycosylation of dimethyl 2-phenylimidazole-4,5-dicarboxylate (I) with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose (II) in the presence of hexamethyldisilazane, chlorotrimethylsilane and trifluoromethanesulfonic acid leads to the imidazole ribofuranoside (III). Then, cyclization of the imidazoledicarboxylate (III) with guanidine (IV), and simultaneous alcoholysis of the ribose ester groups in the presence of methanolic NaOMe gives rise to the target imidazodiazepine ribofuranoside