Molecules 2012, 17(9), 10683-10707; doi:10.3390/molecules170910683
Article

Regiocontrolled Microwave Assisted Bifunctionalization of 7,8-Dihalogenated Imidazo[1,2-a]pyridines: A One Pot Double-Coupling Approach

Emilie Marieemail, Sébastien Boucléemail, Cécile Enguehard-Gueiffier* email and Alain Gueiffieremail
Recherche et Innovation en Chimie Médicinale, UMR INRA 1282 Infectiologie et Santé Publique, Université F. Rabelais, 31 avenue Monge, F-37200 Tours, France
* Author to whom correspondence should be addressed.
Received: 27 July 2012; in revised form: 31 August 2012 / Accepted: 3 September 2012 / Published: 6 September 2012
(This article belongs to the Section Organic Synthesis)
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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.
Keywords: imidazo[1,2-a]pyridine; metallo-catalyzed cross-coupling reaction; microwave irradiation; Suzuki-Miyaura cross-coupling; Sonogashira cross-coupling; cyanation; Buchwald-Hartwig cross-coupling

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MDPI and ACS Style

Marie, E.; Bouclé, S.; Enguehard-Gueiffier, C.; Gueiffier, A. Regiocontrolled Microwave Assisted Bifunctionalization of 7,8-Dihalogenated Imidazo[1,2-a]pyridines: A One Pot Double-Coupling Approach. Molecules 2012, 17, 10683-10707.

AMA Style

Marie E, Bouclé S, Enguehard-Gueiffier C, Gueiffier A. Regiocontrolled Microwave Assisted Bifunctionalization of 7,8-Dihalogenated Imidazo[1,2-a]pyridines: A One Pot Double-Coupling Approach. Molecules. 2012; 17(9):10683-10707.

Chicago/Turabian Style

Marie, Emilie; Bouclé, Sébastien; Enguehard-Gueiffier, Cécile; Gueiffier, Alain. 2012. "Regiocontrolled Microwave Assisted Bifunctionalization of 7,8-Dihalogenated Imidazo[1,2-a]pyridines: A One Pot Double-Coupling Approach." Molecules 17, no. 9: 10683-10707.

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