Copper catalysed regioselective synthesis of pyrimidine substituted Indolizino[8,7-b]indole derivatives via cascade A3 annulation

Abstract

Cu(II) salt has been found to be an efficient catalyst for the regioselective synthesis of a series of novel indolizino [8,7-b]indole derivatives with pyrimidine tethers via three-component annulation of 1-formyl-9H-?-carbolines (Kumujian C), 2-amino-pyrimidines and terminal alkynes. The reactions proceeds through Cu-catalysed A3-coupling followed by intramolecular cyclisation in a cascade manner. The scope of strategy has been exemplified with a library of biologically interesting 25 indolizino [8,7-b]indoles with pyrimidine tethers which mimics several natural products. � 2023 Elsevier Ltd