A synthesis of pyrazino[1, 2-a]indoles via one-pot cascade Ugi condensation and N-annulation under mild conditions. (21st December 2021)

• Record Type: Journal Article
• Authors: Peirow, Reihane; Adib, Mehdi; Mahdavi, Mohammad
• Is Part Of: Tetrahedron letters. Volume 87(2021)
• Publication Date: 2021-12-21
• Subjects: Pyrazino[1 -- 2-a]indole -- Ugi reaction -- N-annulation -- Multi-component reactions -- Indole-2-carboxylic acid; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2021.153547
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Abstract: A novel, one-pot, mild and operationally simple synthetic approach for the synthesis of pyrazino[1, 2- a ]indole derivatives is reported. The reaction proceeds via a 4-component Ugi condensation followed by N -annulation of the intermediate to afford the titled product under metal and acid-free conditions in methanol. The procedure consists of one-step tandem condensation and cyclization of Indole-2-carboxylic acid with isocyanides, phenacylamine hydrochloride and a variety of aromatic aldehydes. This method provides simple access to a wide range of pyrazino[1, 2- a ]indole derivatives in good to excellent yields under ambient temperature.