A mixture of 2.0 g of 1-hydrazinophthalazine hydrochloride, 1.1 g of mesityl
oxide (isoproplyideneacetone) and 100 ml of ethanol, was refluxed for 3
hours. The reaction mixture was concentrated in vacuo and the residue was dissolved in water. The water solution was neutralized with sodium
bicarbonate, salted out and the product was extracted with benzene. The
benzene layer was passed through a comparatively short column of alumina
and the solvent was removed. The residue was crystallized from ether to give
0.7 g of 1-(1,3-dimethyl-2-butenylidene) hydrazinophthalazine, melting point
131°-132°C.
