The Collaborative International Dictionary
Diisatogen
Diisatogen \Di`i*sat"o*gen\, n. [Pref. di- + isatine + -gen.] (Chem.) A red crystalline nitrogenous substance of artificial production, which by reduction passes directly to indigo.
Wiktionary
diisatogen
n. (context chemistry English) A synthetic red crystalline nitrogenous substance which by reduction passes directly to indigo.