Synthesis of 6‐(4‐methyl‐1‐piperazinyl)‐7 H ‐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(1 H )‐quinolinone 9 , was directly cyclized into the corresponding 6‐chloro‐7 H ‐indeno[2,1‐ c ]quinolin‐7‐one 10 or alternatively it was esterified, reduced to the alcohol, chlorinated and cyclized into the 6‐chloro‐7 H ‐indeno[2,1‐ c ]quinoline 8 . Further reaction of the chloroindenoquinoline derivatives with N ‐methylpiperazine afforded the piperazinyl derivatives 4a‐c .