The reactions of 4-substituted-7-aminothieno-[3,4-d]pyridazines and 2-methyl-6-aminothienopyridine-5-thione with electron-poor olefins and acetylenes

Cycloadditions of thienopyridazines and a thienopyridine with electron-poor olefins and acetylenes as dienophiles are described. The nonisolable adducts undergo subsequent loss of hydrogen sulfide to give substituted phthalazines and substituted isoquinolines, respectively. © 1997 John Wiley & Sons, Inc.