In the reactions with ammonia and alkylamines, perfluoro-3-ethylindene is more reactive than perfluoro-1-ethylideneindan, whereby the last two compounds undergo mutual conversion in the presence of F−. In the interaction of perfluoro-1-ethylideneindan with aqueous amines, products of the substitution of the vinyl F atom in the initial compound are obtained; in the case of dry amines in the presence of CsF, the products of the substitution of the F atom at the double bond of perfluoro-3-ethylindene are chiefly obtained. The monoamino derivatives, which contain an available atom of H, are converted to the disubstituted derivatives by the action of an excess of the amines. Both the amine and the hydroxy anion may thereby emerge as the nucleophile in the reaction of 2-aminoperfluoro-3-ethylindene, as well as perfluoro-1-ethylideneindan, with aqueous dialkylamines. The perfluoro-1-vinylindan and aqueous NH3yield 1-(aminocyanomethylene)octafluoroindan and 2-amino-3-(iminocyanomethyl)hexafluoroindene; and perfluoro-1-methyleneindan yields 2-amino-3-cyanohexafluoroindene. The last is formed together with 2-aminoperfluoro-3-methylindene in the reaction of perfluoro-3-methylindene with aqueous NH