☆ 4.5 Article

Lewis Acid-Catalyzed Selective Synthesis of Diversely Substituted Indolo- and Pyrrolo[1,2-a]quinoxalines and Quinoxalinones by Modified Pictet-Spengler Reaction

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY (2011)

期刊

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY

卷 2011, 期 34, 页码 6998-7010

出版社

WILEY-V C H VERLAG GMBH

DOI: 10.1002/ejoc.201101013

关键词

Nitrogen heterocycles; Fused-ring systems; Polycycles; Cross-coupling; Cyclization; Lewis acids

类别

Chemistry, Organic

资金

Defence Research & Development Organization (DRDO)
Department of Science and Technology (DST)
University Grants Commission (UGC)
University of Delhi (DU-DST PURSE)

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摘要

An efficient tandem process for the selective synthesis of 1,2-annulated a-fused quinoxalines using benzotriazole methodology by a modified PictetSpengler reaction is described. The approach involves the reaction of arylamines 4 with aromatic aldehydes 5 to furnish 6-endo-dig-cyclized products. Dihydroquinoxalines 6 were selectively obtained by using AlCl3 in tetrahydrofuran (THF) at room temperature for two hours. However, after ten hours, quinoxalines 7 were obtained exclusively in excellent yields. A series of biologically important fluoro- and piperazenyl-substituted quinoxalines were also synthesized. This developed methodology also provides access to a novel tandem synthesis of quinoxalinones 9.

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