Regioselective three-component synthesis of novel indeno[1,2-b]-pyrazolo[4,3-e]pyridines-fused derivatives of 4-azafluorenone alkaloid

New fused indeno[1,2-b]pyridine derivatives have been prepared in a multicomponent reaction from benzaldehydes, indanedione and the appropriate aminoheteroaryl compound. The simple methodology permitted the syntheses of a series of indeno[1,2-b]pyrazolo[4,3-e]pyridines 4 from 5-aminopyrazol 1 and modulated by the corresponding benzaldehyde 2.