Oligomers with four 3,4‐quinolinediyl units and α,ω‐bis (4‐chloro‐3‐quinolinylthio)alkanes

Starting from the reaction of thioquinanthrene 1 with sodium methoxide followed by the reaction with α,ω‐dihalogenoalkanes, title bis‐methoxy oligomers 4a‐c with four 3,4‐quinolinediyl units were prepared (40–91%). Acid catalysed hydrolysis of methoxy groups in 4a‐c gave tetramers 5a‐c (46–94%) with two 4(1 H )‐quinolinone functions. The reactions of bis‐quinolinones 5a‐c with phosphoryl chloride in DMF run as deoxo‐chlorination and afforded tide dichlorotetramers 6a‐c (51–66%) with 4‐chloroquinolinyl groups. The treatment of bis‐methoxy tetramers 4a ‐c with boiling phosphoryl chloride led to title α,ω‐bis(4‐chloro‐3‐quinolinylthio)alkanes 7a‐c (52–56%) and thioquinanthrene (65–70%).