Isomerism of isatin-?-aroylhydrazones

Reactions of diorganotin(IV) oxides with isatin 3- and 2-thiosemicarbazones and with isatin 2,3-bis(thiosemicarbazone): influence of diphenyldithiophosphinic acid (isatin = 1H-indole-2,3-dione)

“…1 for numbering scheme). H 2 L II cannot be obtained by direct condensation because, unlike other α-dicarbonyl compounds, isatin only condenses with one molecule of thiosemicarbazide at position 3, so H 2 L II was synthesized by a method similar to that used by Dmitrukha and Pel'kis 15 for isatin 2-arylhydrazones. A solution of thiosemicarbazide (0.7 g, 0.01 mol) in 100 mL of absolute ethanol was added to a solution of 1.2 g (0.01 mol) of previously pre-pared 16 2-methoxy-3H-3-indolone in 70 mL of dry benzene.…”