Preparation of the Monohydrazone of 2-Acetyl-I, 3-indan-diene.-A mixture of 2-acetyl-1, 3- indandione (1.9 g., 0.01 mole), 100 ml. of absolute ethanol and anhydrous hydrazine (0.34 g., 0.01 mole) was heated at reflux with vigorous stirring. After three hours the reaction mixture was cooled and filtered. The yellow crystals were washed with cold ethanol. The material was insoluble in water, ethyl alcohol and ethyl acetate but soluble in hot ethyl ...