Synthesis of 6‐(4‐methyl‐1‐piperazinyl)‐7H‐indeno[2,1‐c]‐quinoline derivatives as potential 5‐HT receptor ligands

Two synthetic pathways for the achievement of the title compounds are reported. The key intermediate, namely 3‐carboxy‐4‐phenyl‐2(1H)‐quinolinone 9, was directly cyclized into the corresponding 6‐chloro‐7H‐indeno[2,1‐c]quinolin‐7‐one 10 or alternatively it was esterified, reduced to the alcohol, chlorinated and cyclized into the 6‐chloro‐7H‐indeno[2,1‐c]quinoline 8. Further reaction of the chloroindenoquinoline derivatives with N‐methylpiperazine afforded the piperazinyl derivatives 4a‐c.