alkyl- and arylalkyl halogenides and with tetraacetylribofuranose regiospecifically to the corresponding 3-substituted-6-aminouracil derivatives 1–10. The reaction is catalyzed by AlCl3 or, with the exception of the ribose derivative, more effectively by iodine. The described newsynthesis offers the first general access to 3-substituted 6-aminouracils.