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(1H)-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%).