Facile Synthesis of Polysubstituted Imidazoles through CBr<sub>4</sub>-Mediated Tandem Cyclization of Amidines with 1,3-Dicarbonyl Compounds or Ketones
A facile approach to synthesize polysubstituted imidazoles via CBr4 mediated tandem cyclization of amidine with 1,3-dicarbonyl or ketone is described. This metal-free cascade reaction employed CBr4 as promoter and was carried out with a simple operation under mild conditions.
Catalyst-Free Preparation of 1,2,4,5-Tetrasubstituted Imidazoles from a Novel Unexpected Domino Reaction of 2-Azido Acrylates and Nitrones
作者:Bao Hu、Zhao Wang、Ning Ai、Jie Zheng、Xing-Hai Liu、Shang Shan、Zhongwen Wang
DOI:10.1021/ol202650z
日期:2011.12.16
A highly efficient and convenient method for the synthesis of 1,2,4,5-tetrasubstitutedimidazoles from readily accessible 2-azidoacrylates and nitrones has been developed. This reaction proceeded under mild conditions without the assistance of any metal, acid, or base.
A new practical carbon-nitrogen bond formation reaction of amidines with ethyl acetoacetate to synthesize imidazoles via oxidative cyclization in the presence of bromide. The reactions were occured under mild and metal-free conditions.