CARBON-SULFUR AND CARBON-SELENIUM DOUBLE-BOND FORMATION THROUGH THIOLYSIS AND SELENOLYSIS OF 4-METHYLSULFANYL-SUBSTITUTED PYRIDINIUM AND QUINOLINIUM HALIDES

4-Methylsulfanylpyridinium and -quinolinium salts 3 and 4 with alkyl g roups such as methyl, allyl, benzyl, ethoxycarbonylmethyl, benzoylmeth yl on the nitrogen atom were prepared by the Menschutkin-type reaction and some of them caused to react under either the thiolysis or seleno lysis reaction conditions. N-Substituted pyridine-4-thiones 5a-c and q uinoline-4-thiones 6a-e were formed at different rates in high isolate d yield. On the other hand, two N-alkyl-4-seleno-pyridones 7a,b togeth er with three 4-selenoquinolones 8a,b,c were also produced in high che mical purity and characterized spectroscopically. In addition, 4-sulfa nylpyridone 12 and 4-selenopyridone 13 with a N-tert-butyl group were obtained via Zincke's salt 9. The overall process provides a useful al ternative to the otherwise difficult direct N-alkylation of thioxo-and selenoxopyridine systems.