Synthesis of two linear indoloquinolines i.e. 6H-indolo[2,3-b]quinoline & 11-hydroxy-10H-indolo[3,2-b]quinoline, and spiro[2H-indole-2,3′-oxindole] from a common intermediate, (2-nitrophenyl)methylidene-dihydro-indolone derivative is described using microwave-mediated reductive cyclization as the key step.
![Graphical abstract: Microwave-assisted reductive cyclization: an easy entry to the indoloquinolines and spiro[2H-indole-2,3′-oxindole]](http://hg.y866.cn/compound/lib/scimg/usr/1/C4RA02814G.jpg)
