1-Hydrazinophthalazine pyruvic hydrazone 2-(1-Phthalazinylhydrazono)-propanoic acid 2-(1-Phthalazinylhydrazono)propanoic acid 65846-20-0 67536-13-4 Hydralazine pyruvic acid hydrazone Propanoic acid, 2-(1-phthalazinylhydrazono)- Pyruvic acid, 2-(1-phthalazinyl)hydrazone