Chemodivergent synthesis of N-(pyridin-2-yl)amides and 3-bromoimidazo[1,2-a]pyridines from α-bromoketones and 2-aminopyridines
2019
Liu, Yanpeng | Lü, Lixue | Zhou, Haipin | Xu, Feijie | Ma, Cong | Huang, Zhangjian | Xu, Jinyi | Xu, Shengtao
N-(Pyridin-2-yl)amides and 3-bromoimidazo[1,2-a]pyridines were synthesized respectively from α-bromoketones and 2-aminopyridine under different reaction conditions. N-(Pyridin-2-yl)amides were formed in toluene via C–C bond cleavage promoted by I₂ and TBHP and the reaction conditions were mild and metal-free. Whereas 3-bromoimidazopyridines were obtained in ethyl acetate via one-pot tandem cyclization/bromination when only TBHP was added, the cyclization to form imidazopyridines was promoted by the further bromination, no base was needed, and the versatile 3-bromoimidazopyridines could be further transferred to other skeletons.
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