What is a white crystalline nitrogenous substance (C8H7NO) of the indol group, obtained by the reduction of dioxindol. It is a so-called lactam compound called?

oxindol — A white crystalline nitrogenous substance (C8H7NO) of the indol group, obtained by the reduction of dioxindol. It is a so-called lactam compound. (Webster's 1913.)

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