SYNTHESIS OF 3-BROMOQUINOLINE-2(1H)-THIONES AND 2-(ALKYLSULFANYL)-3-BROMOQUINOLINES BASED ON THE REACTION OF 2-(2,2-DIBROMOETHENYL)PHENYL ISOTHIOCYANATES WITH BUTYLLITHIUM

The synthesis of 3-bromoquinoline-2(1H)-thiones and 2-(alkylsulfanyl)-3-bromoquinolines from readily available starting materials was accomplished. Thus, 2-(2,2-dibromoethenyl)phenyl isothiocyanates were treated with butyllithium to afford, after aqueous workup, 3-bromoquinoline-2(1H)-thiones. When haloalkanes were added prior to workup, 2-(alkylsulfanyl)-3-bromoquinolines were obtained. An elaboration of one of these compounds to a thieno[2,3-b]quinoline derivative and one-pot preparation of 3-substituted quinoline-2(1H)-thiones were also achieved.