Ring-chain tautomerism of vinylogs of 2(3)-amino derivatives of heterocyclic o-hydroxy aldehydes

Previously unknown vinylogs of 2(3)-aminomethylene-substituted benzob]thiophene-3-one, 1-methyloxindole, 1-methylindoxyl, benzob]furan-3-one, and indan-1,3-dione have been synthesized. Their tautomeric transformations have been studied by methods of UV, IR, and PMR spectroscopy. It has been shown that the introduction of a substituent into the position of a dienic chain favors the appearance of the cyclic form.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1171–1176, September, 1984.