title: Synthesis of imidazo[4,5-c]pyrazoles via copper-catalyzed amidine cyclization.
abstract: A new synthetic approach to 4-substituted imidazo[4,5-c]pyrazoles is proposed on the basis of the N'-(4-halopyrazol-5-yl)amidine cyclization under the conditions of copper-catalyzed cross-coupling reactions. Using 5-aminopyrazoles and copper catalysts as starting materials, the method is inexpensive and convenient and allows a wide range of substituents at all positions of the imidazo[4,5-c]pyrazole nucleus.
authors.affiliation: Institute of Organic Chemistry of NAS of Ukraine, 5 Murmanska str., Kyiv, 02094, Ukraine. kliubchak@gmail.com
authors.forename: Kostiantyn
authors.initials: K
authors.lastname: Liubchak
authors.forename: Andrey
authors.initials: A
authors.lastname: Tolmachev
authors.forename: Kostiantyn
authors.initials: K
authors.lastname: Nazarenko
mesh_terms: D000578:Amidines / Q000737:chemistry*; D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D003500:Cyclization; D007093:Imidazoles / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry*
chemical_list: D000578:Amidines; D003432:Cross-Linking Reagents; D007093:Imidazoles; D011720:Pyrazoles; C574413:imidazo(4,5-c)pyrazole; D003300:Copper