Pyridinethiones XIV. Reactions of 2- and 4-Alkylthiopyridines; Synthesis of 1,6- and 2,7-Naphthyridines via 2-Methylene-1,2-dihydro- and 4-Methylene-1,4-dihydropyridines

Article abstract of DOI:10.1055/s-1987-27927

2,4-Bismethylthiopyridinium iodides prepared from 2(1H)-pyridinethiones react regioselectively with active methylene compounds, preferentially at the 4-position, yielding 4-alkylidene-1,4-dihydropyridines.The corresponding 4-benzylthio-2-methylthiopyridin