title: Regiocontrolled microwave assisted bifunctionalization of 7,8-dihalogenated imidazo[1,2-a]pyridines: a one pot double-coupling approach.
abstract: The reactivity of the 7-chloro-8-iodo- and 8-chloro-7-iodoimidazo[1,2-a]pyridines 1a-e diversely substituted on the 2 position, towards Suzuki-Miyaura, Sonogashira, and Buchwald-Hartwig cross-coupling reactions as well as cyanation was evaluated. Various methodologies are proposed to introduce aryl, heteroaryl, alkyne, amine or cyano groups in the two positions depending on the nature of the substituent present in position 2. In both series, the substitution of the iodine atom was totally regioselective and the difficulty was to substitute the chlorine atom in a second step. Until now, only hetero(aryl) groups could be introduced though Suzuki-Miyaura cross-coupling. We overcame this problem evaluating both regioisomers in parallel. The double coupling approach was also studied allowing the one pot Suzuki/Suzuki, cyanation/Sonogashira and cyanation/Buchwald reactions leading to polyfunctionnalized imidazo[1,2-a]pyridines.
authors.affiliation: Recherche et Innovation en Chimie Médicinale, UMR INRA 1282 Infectiologie et Santé Publique, Université F. Rabelais, 31 avenue Monge, F-37200 Tours, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Marie
authors.forename: Sébastien
authors.initials: S
authors.lastname: Bouclé
authors.forename: Cécile
authors.initials: C
authors.lastname: Enguehard-Gueiffier
authors.forename: Alain
authors.initials: A
authors.lastname: Gueiffier
mesh_terms: D002384:Catalysis; D003432:Cross-Linking Reagents / Q000737:chemistry*; D008872:Microwaves; D015394:Molecular Structure; D011725:Pyridines / Q000737:chemistry*
chemical_list: D003432:Cross-Linking Reagents; D011725:Pyridines