title: Clarification of the ring-closure of certain 4,5-diaminopyrimidines to 6-substituted 8-alkylpurines.
mesh_terms: D000998:Antiviral Agents / Q000138:chemical synthesis*; D003500:Cyclization; D003959:Diamines; D007042:Hypoxanthines / Q000138:chemical synthesis; D011687:Purines / Q000138:chemical synthesis*; D011743:Pyrimidines
chemical_list: D000998:Antiviral Agents; D003959:Diamines; D007042:Hypoxanthines; D011687:Purines; D011743:Pyrimidines