Synthesis, transformations and halocyclization of 8-(Prop-2-ynylsulfanyl)quinoline and 8-(2-Bromoprop-2-enylsulfanyl)quinoline

8-Quinolyl-(2-propynyl)sulfide is isomerized in a superbasic medium, is oxidized under the action of hydrogen peroxide to the corresponding sulfoxide, reacts with halogens to form dihydrothiazino[2,3,4-ij]quinolium systems, which are also obtained by halocyclization of 8-quinolyl-(2-bromo-2-propenyl)sulfide.