Abstract
Reaction of 5-mercaptoquinoline with phenylacetylene (KOH, dioxane, 160–170°C, 1 h, autoclave) gives (along with the normal adduct Z-5-styrylthioquinoline) 3-phenylthiopyrano[4,3,2-d,e]quinoline, the product of a unique intramolecular nucleophilic substitution of hydrogen by carbanion at position 4 of the quinoline ring.